Volvo

Fault Condition: The FMI of 3 (Voltage High) will be displayed for all code faults that result from the fan speed being less than 20 rpm.
High engine coolant temperature could occur and cause engine shutdown.

If fault code PID 26 is set with FMI 3, fault code SID 211 may also be set.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 5 and a good ground.
If continuity exists, locate and repair the short circuit to ground in the supply voltage circuit between the electronic fan drive and the EMS Module.
2) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 5 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the supply voltage circuit between the electronic fan drive and the EMS Module.
3) Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 5 and a good ground. If continuity exists, replace the electronic fan drive assembly.
4) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 1 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the sensor signal circuit between the electronic fan drive and the EMS Module.
5) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 1 and a good ground.
If continuity exists, locate and repair the short circuit in the electronic fan drive signal line.
6) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 39 and electronic fan drive harness connector pin 2.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive ground line.
7) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 1 and a good ground (see Figure 14).
If continuity exists, replace the electronic fan drive assembly.
8) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 7 and electronic fan drive harness connector pin 5.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive supply line.
9) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 35 and electronic fan drive harness connector pin 1.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive signal line.
10) Disconnect EMS Module connector A. Visually inspect the EMS Module and connector A for broken, damaged, or shorted pins. If any damage is found, repair or replace the damaged component.
11) Replace the electronic fan drive with a known good unit. Restore all electrical connections an retest the system. If blink code PID 26 is still active, install the original electronic fan drive and replace the EMS Module.
If blink code PID 26 is NOT active, replacing the electronic fan drive solved the problem. Check all connectors to ensure proper connections.

Volvo All Engines (2004 Emissions) Fault Code: PID 26 FMI 8 Fan Speed

Fault Condition: High engine coolant temperature could occur and cause engine shutdown.

If fault code PID 26 is set with FMI 3, fault code SID 211 may also be set.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 5 and a good ground.
If continuity exists, locate and repair the short circuit to ground in the supply voltage circuit between the electronic fan drive and the EMS Module.
2) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 5 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the supply voltage circuit between the electronic fan drive and the EMS Module.
3) Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 5 and a good ground. If continuity exists, replace the electronic fan drive assembly.
4) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 1 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the sensor signal circuit between the electronic fan drive and the EMS Module.
5) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 1 and a good ground.
If continuity exists, locate and repair the short circuit in the electronic fan drive signal line.
6) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 39 and electronic fan drive harness connector pin 2.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive ground line.
7) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 1 and a good ground (see Figure 14).
If continuity exists, replace the electronic fan drive assembly.
8) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 7 and electronic fan drive harness connector pin 5.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive supply line.
9) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 35 and electronic fan drive harness connector pin 1.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive signal line.
10) Disconnect EMS Module connector A. Visually inspect the EMS Module and connector A for broken, damaged, or shorted pins. If any damage is found, repair or replace the damaged component.
11) Replace the electronic fan drive with a known good unit. Restore all electrical connections an retest the system. If blink code PID 26 is still active, install the original electronic fan drive and replace the EMS Module.
If blink code PID 26 is NOT active, replacing the electronic fan drive solved the problem. Check all connectors to ensure proper connections.

Fault Condition: High engine coolant temperature could occur and cause engine shutdown.

If fault code PID 26 is set with FMI 3, fault code SID 211 may also be set.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 5 and a good ground.
If continuity exists, locate and repair the short circuit to ground in the supply voltage circuit between the electronic fan drive and the EMS Module.
2) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 5 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the supply voltage circuit between the electronic fan drive and the EMS Module.
3) Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 5 and a good ground. If continuity exists, replace the electronic fan drive assembly.
4) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Turn the ignition key ON. Measure the voltage between electronic fan drive harness connector pin 1 and a good ground.
If voltage is present, locate and repair the short circuit to voltage in the sensor signal circuit between the electronic fan drive and the EMS Module.
5) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between electronic fan drive harness connector pin 1 and a good ground.
If continuity exists, locate and repair the short circuit in the electronic fan drive signal line.
6) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 39 and electronic fan drive harness connector pin 2.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive ground line.
7) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between the sensor side of electronic fan drive connector pin 1 and a good ground (see Figure 14).
If continuity exists, replace the electronic fan drive assembly.
8) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 7 and electronic fan drive harness connector pin 5.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive supply line.
9) Disconnect EMS Module connector A. Disconnect the electronic fan drive harness connector. Check for continuity between EMS Module harness connector A pin 35 and electronic fan drive harness connector pin 1.
If there is NO continuity, locate and repair the open circuit in the electronic fan drive signal line.
10) Disconnect EMS Module connector A. Visually inspect the EMS Module and connector A for broken, damaged, or shorted pins. If any damage is found, repair or replace the damaged component.
11) Replace the electronic fan drive with a known good unit. Restore all electrical connections an retest the system. If blink code PID 26 is still active, install the original electronic fan drive and replace the EMS Module.
If blink code PID 26 is NOT active, replacing the electronic fan drive solved the problem. Check all connectors to ensure proper connections.

Fault Condition: The Electronic Malfunction Lamp (EML) will turn on and PID 354 will set when the EMS Module senses that the Intake Air Temperature and Humidity (IATH) Sensor signal voltage is less than 0.4 volts or greater than 4.2 volts. If the Intake Air Temperature and Humidity (IATH) Sensor voltage returns to between 0.4 volts and 4.2 volts, the fault will become inactive.

Note: To ensure that condensation on the sensor has been removed, diagnostics can only be performed after the engine has run for 5 minutes or more.

Run the engine for 5 minutes or more and then use a diagnostic computer to monitor the relative humidity portion of the sensor. If the relative humidity portion of the sensor displayed on the diagnostic tool accurately reflects the actual humidity, the fault has become inactive. Check the connectors at the Intake Air Temperature and Humidity (IATH) Sensor and the Engine Management System (EMS) Module for proper connections.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 7 and IATH Sensor harness
connector pin 1. If there is NO continuity, locate and repair the open between IATH Sensor connector pin 1 and EMS Module connector A pin 7.
2) Disconnect the Intake Air Temperature and Humidity (IATH). Disconnect Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 23 and IATH Sensor harness connector pin 2. If there is NO continuity, locate and repair the open in the IATH Sensor signal line.
3) Disconnect the Intake Air Temperature and Humidity (IATH). Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module connector A pin 23 and all the other pins on EMS Module connectors A and B. If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit. If there is NO continuity, there is a short circuit to ground somewhere else in the harness. Locate and repair the short circuit to ground.
4) Disconnect the IATH Sensor and the Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 7 and a good ground. If continuity exists, locate and repair the short circuit to ground in the voltage reference line.
5) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Measure the voltage between EMS Module harness connector A pin 7 and a good
ground. If the measured voltage is greater than 0.5 volts present, the IATH voltage reference line is shorted to voltage. Locate and repair the short circuit to voltage.
6) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor harness connector. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 23 and all other pins on EMS Module harness connectors A and B. If continuity exists, EMS Module harness connector A pin 23 is shorted to one of the other EMS Module circuits. Locate and
repair the short circuit. If there is NO continuity, the sensor signal line is shorted to voltage somewhere else in the harness. Locate and repair the short circuit to voltage.
7) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 7 and/or 23 and all other pins on EMS Module harness connectors A and B. If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit.
8) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Measure the voltage between EMS Module harness connector A pin 11 and a good
ground. If the measured voltage is greater than 0.5 volts, the sensor return line is shorted to voltage. Locate and repair the short circuit and replace the EMS Module.
9) Connect the Intake Air Temperature and Humidity (IATH) Sensor. Connect the diagnostic computer. Turn the ignition key ON. Flex the IATH Sensor connector and harness section near the connector. If code PID 354 is NOT present, the ground circuit of the IATH Sensor or harness connector may have been loose. Repair the loose connection.
10) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 11 and all other pins on EMS Module harness connectors A and B. If continuity exists, pin 11 is shorted to voltage on one of the other EMS Module circuits. Locate and repair the short circuit and replace the EMS Module. If there is NO continuity, replace the EMS Module and retest the system.
11) Replace the Intake Air Temperature and Humidity (IATH) Sensor. Turn the ignition key ON. If PID 354 is still active, reinstall the original IATH Sensor and replace the Engine Management System (EMS) Module. If PID 354 is NOT present, replacing the IATH Sensor has solved the problem. Check all connectors to ensure proper connections.
12) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Visually inspect both sides of the EMS Module harness connector A for a repairable
open. If the pins feels loose, repair the connector. If the connector is NOT repairable, replace the connector. If the pins are making good contact, replace the EMS Module and retest the system.
13) Connect EMS Module harness connectors A and B. Connect the IATH Sensor connector. Turn the ignition key ON. If code PID 354 is still active, replace the EMS Module and retest the system. If code PID 354 is NOT active, the diagnostic procedures have corrected the problem. Check all connectors to ensure proper contact.

Fault Condition: The Electronic Malfunction Lamp (EML) will turn on and PID 354 will set when the EMS Module senses that the Intake Air Temperature and Humidity (IATH) Sensor signal voltage is less than 0.4 volts or greater than 4.2 volts. If the Intake Air Temperature and Humidity (IATH) Sensor voltage returns to between 0.4 volts and 4.2 volts, the fault will become inactive.

Note: To ensure that condensation on the sensor has been removed, diagnostics can only be performed after the engine has run for 5 minutes or more.

Run the engine for 5 minutes or more and then use a diagnostic computer to monitor the relative humidity portion of the sensor. If the relative humidity portion of the sensor displayed on the diagnostic tool accurately reflects the actual humidity, the fault has become inactive. Check the connectors at the Intake Air Temperature and Humidity (IATH) Sensor and the Engine Management System (EMS) Module for proper connections.

Possible repairs:

Turn the ignition key OFF first.

1) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 7 and IATH Sensor harness
connector pin 1. If there is NO continuity, locate and repair the open between IATH Sensor connector pin 1 and EMS Module connector A pin 7.
2) Disconnect the Intake Air Temperature and Humidity (IATH). Disconnect Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 23 and IATH Sensor harness connector pin 2. If there is NO continuity, locate and repair the open in the IATH Sensor signal line.
3) Disconnect the Intake Air Temperature and Humidity (IATH). Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module connector A pin 23 and all the other pins on EMS Module connectors A and B. If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit. If there is NO continuity, there is a short circuit to ground somewhere else in the harness. Locate and repair the short circuit to ground.
4) Disconnect the IATH Sensor and the Engine Management System (EMS) Module connector A. Check for continuity between EMS Module connector A pin 7 and a good ground. If continuity exists, locate and repair the short circuit to ground in the voltage reference line.
5) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Measure the voltage between EMS Module harness connector A pin 7 and a good
ground. If the measured voltage is greater than 0.5 volts present, the IATH voltage reference line is shorted to voltage. Locate and repair the short circuit to voltage.
6) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor harness connector. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 23 and all other pins on EMS Module harness connectors A and B. If continuity exists, EMS Module harness connector A pin 23 is shorted to one of the other EMS Module circuits. Locate and
repair the short circuit. If there is NO continuity, the sensor signal line is shorted to voltage somewhere else in the harness. Locate and repair the short circuit to voltage.
7) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 7 and/or 23 and all other pins on EMS Module harness connectors A and B. If continuity exists, the signal line is shorted to one of the other EMS Module circuits. Locate and repair the short circuit.
8) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Measure the voltage between EMS Module harness connector A pin 11 and a good
ground. If the measured voltage is greater than 0.5 volts, the sensor return line is shorted to voltage. Locate and repair the short circuit and replace the EMS Module.
9) Connect the Intake Air Temperature and Humidity (IATH) Sensor. Connect the diagnostic computer. Turn the ignition key ON. Flex the IATH Sensor connector and harness section near the connector. If code PID 354 is NOT present, the ground circuit of the IATH Sensor or harness connector may have been loose. Repair the loose connection.
10) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connectors A and B. Check for continuity between EMS Module harness connector A pin 11 and all other pins on EMS Module harness connectors A and B. If continuity exists, pin 11 is shorted to voltage on one of the other EMS Module circuits. Locate and repair the short circuit and replace the EMS Module. If there is NO continuity, replace the EMS Module and retest the system.
11) Replace the Intake Air Temperature and Humidity (IATH) Sensor. Turn the ignition key ON. If PID 354 is still active, reinstall the original IATH Sensor and replace the Engine Management System (EMS) Module. If PID 354 is NOT present, replacing the IATH Sensor has solved the problem. Check all connectors to ensure proper connections.
12) Disconnect the Intake Air Temperature and Humidity (IATH) Sensor. Disconnect Engine Management System (EMS) Module connector A. Visually inspect both sides of the EMS Module harness connector A for a repairable
open. If the pins feels loose, repair the connector. If the connector is NOT repairable, replace the connector. If the pins are making good contact, replace the EMS Module and retest the system.
13) Connect EMS Module harness connectors A and B. Connect the IATH Sensor connector. Turn the ignition key ON. If code PID 354 is still active, replace the EMS Module and retest the system. If code PID 354 is NOT active, the diagnostic procedures have corrected the problem. Check all connectors to ensure proper contact.

Fault Condition: The Compressor Discharge Temperature code will set if the calculated discharge temperature has exceeded 446°F (230°C) for 25 seconds. The fault will become inactive if the calculated compressor discharge temperature is below 410°F (210°C). Engine power may be reduced when the calculated compressor discharge temperature exceeds 446°F (230°C). This temperature fault code can only be set while the vehicle is driven.

Higher horsepower engines may generate excessive compressor discharge temperatures. Refer to message status information rather than fault codes for this situation.

Possible repairs:

1) Verify that code PID 404 is set. If code PID 404 is not set, the problem may be intermittent. Check for any loose, corroded, and or damaged terminals at the Engine Management System (EMS) Module. Repair and or replace as necessary.
2) The primary cause for high compressor temperature is high inlet air temperature. The inlet air should be no more than 20°F (7°C) above ambient temperature. Check for sources of underhood air getting into the air intake duct. Check all air intake ducts for cracks, damaged clamps and improper connections. If any cracks, damaged clamps or improper connections are found, repair and replace as necessary. If no cracks, damaged clamps or improper connections are found, the problem may be intermittent. Check for any loose, corroded, and or damaged terminals at the Engine Management System (EMS) Module. Repair and or replace as necessary.

Fault Condition: Code PID 412 will set with FMI 0 if the EGR ECU detects the exhaust gas temperature exceeds 365°F (185°C) for 30 minutes, 410°F (210°C) for 25 seconds or 455°F (235°C) for 3 seconds. Code PID 412 will set with FMI 3 if the EGR ECU detects a short circuit to voltage in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 4 if the EGR ECU detects a short circuit to ground in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 5 if the EGR ECU detects an open in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 9 if the EGR ECU signal is missing on the J1939 serial data lines.

Possible repairs:

Turn the ignition key OFF first.

1) If code PID 412 is NOT set, wiggle the harness and connectors to try to set the code. Visually inspect the exhaust gas temperature probe connector and wires for poor connections.
2) Check the Failure Mode Identifier (FMI) using a diagnostic computer. If the FMI is 0 (valid high), check for a faulty EGR cooler. If the FMI is 3 (voltage high/open) or 5 (current low/open), replace the EGR Mass Flow Sensor assembly and retest the system. If the FMI is 4 (voltage low), inspect the harness that connects the exhaust gas temperature probe to the EGR ECU and look for any areas where the insulation has worn through and is touching ground. Repair the short to ground if possible; otherwise, replace the EGR Mass Flow Sensor assembly.
3) Remove connector A from the EGR ECU. Turn the ignition key ON. Check for battery voltage (+12V) between pin 2 of EGR ECU connector A and a known good ground. If battery voltage is NOT present, a problem exists between EGR ECU connector A pin 2 and the power supply from the EMS Relay. Inspect the EGR ECU and EMS Relay connectors for damaged or loose pins. If the connectors are in good condition, locate and repair the open circuit, and retest the system.
4) Turn the ignition key OFF. Remove connector A from the EGR ECU. Measure the resistance between EGR ECU connector A pin 1 and a known good ground. If the measured resistance does NOT indicate acceptable continuity to ground, a problem exists between EGR ECU connector A and ground. Locate and repair the problem and retest the system.
5) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 52 and EGR ECU connector A pin 3. If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module and the EGR ECU.
6) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 56 and EGR ECU connector A pin 6 . If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module
and the EGR ECU.
7) Replace the EGR ECU and Mass Flow Sensor Assembly with a known good unit. Check the system for codes. If Code PID 412 is still set, reinstall the original EGR ECU and Mass Flow Sensor Assembly and replace the Engine
Management System (EMS) Module. Retest the system. If Code PID 412 is NOT set, replacing the EGR ECU and Mass Flow Sensor Assembly has corrected the problem.

Fault Condition: Code PID 412 will set with FMI 0 if the EGR ECU detects the exhaust gas temperature exceeds 365°F (185°C) for 30 minutes, 410°F (210°C) for 25 seconds or 455°F (235°C) for 3 seconds. Code PID 412 will set with FMI 3 if the EGR ECU detects a short circuit to voltage in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 4 if the EGR ECU detects a short circuit to ground in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 5 if the EGR ECU detects an open in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 9 if the EGR ECU signal is missing on the J1939 serial data lines.

Possible repairs:

Turn the ignition key OFF first.

1) If code PID 412 is NOT set, wiggle the harness and connectors to try to set the code. Visually inspect the exhaust gas temperature probe connector and wires for poor connections.
2) Check the Failure Mode Identifier (FMI) using a diagnostic computer. If the FMI is 0 (valid high), check for a faulty EGR cooler. If the FMI is 3 (voltage high/open) or 5 (current low/open), replace the EGR Mass Flow Sensor assembly and retest the system. If the FMI is 4 (voltage low), inspect the harness that connects the exhaust gas temperature probe to the EGR ECU and look for any areas where the insulation has worn through and is touching ground. Repair the short to ground if possible; otherwise, replace the EGR Mass Flow Sensor assembly.
3) Remove connector A from the EGR ECU. Turn the ignition key ON. Check for battery voltage (+12V) between pin 2 of EGR ECU connector A and a known good ground. If battery voltage is NOT present, a problem exists between EGR ECU connector A pin 2 and the power supply from the EMS Relay. Inspect the EGR ECU and EMS Relay connectors for damaged or loose pins. If the connectors are in good condition, locate and repair the open circuit, and retest the system.
4) Turn the ignition key OFF. Remove connector A from the EGR ECU. Measure the resistance between EGR ECU connector A pin 1 and a known good ground. If the measured resistance does NOT indicate acceptable continuity to ground, a problem exists between EGR ECU connector A and ground. Locate and repair the problem and retest the system.
5) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 52 and EGR ECU connector A pin 3. If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module and the EGR ECU.
6) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 56 and EGR ECU connector A pin 6 . If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module
and the EGR ECU.
7) Replace the EGR ECU and Mass Flow Sensor Assembly with a known good unit. Check the system for codes. If Code PID 412 is still set, reinstall the original EGR ECU and Mass Flow Sensor Assembly and replace the Engine
Management System (EMS) Module. Retest the system. If Code PID 412 is NOT set, replacing the EGR ECU and Mass Flow Sensor Assembly has corrected the problem.

Fault Condition: Code PID 412 will set with FMI 0 if the EGR ECU detects the exhaust gas temperature exceeds 365°F (185°C) for 30 minutes, 410°F (210°C) for 25 seconds or 455°F (235°C) for 3 seconds. Code PID 412 will set with FMI 3 if the EGR ECU detects a short circuit to voltage in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 4 if the EGR ECU detects a short circuit to ground in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 5 if the EGR ECU detects an open in the exhaust gas temperature probe circuit. Code PID 412 will set with FMI 9 if the EGR ECU signal is missing on the J1939 serial data lines.

Possible repairs:

Turn the ignition key OFF first.

1) If code PID 412 is NOT set, wiggle the harness and connectors to try to set the code. Visually inspect the exhaust gas temperature probe connector and wires for poor connections.
2) Check the Failure Mode Identifier (FMI) using a diagnostic computer. If the FMI is 0 (valid high), check for a faulty EGR cooler. If the FMI is 3 (voltage high/open) or 5 (current low/open), replace the EGR Mass Flow Sensor assembly and retest the system. If the FMI is 4 (voltage low), inspect the harness that connects the exhaust gas temperature probe to the EGR ECU and look for any areas where the insulation has worn through and is touching ground. Repair the short to ground if possible; otherwise, replace the EGR Mass Flow Sensor assembly.
3) Remove connector A from the EGR ECU. Turn the ignition key ON. Check for battery voltage (+12V) between pin 2 of EGR ECU connector A and a known good ground. If battery voltage is NOT present, a problem exists between EGR ECU connector A pin 2 and the power supply from the EMS Relay. Inspect the EGR ECU and EMS Relay connectors for damaged or loose pins. If the connectors are in good condition, locate and repair the open circuit, and retest the system.
4) Turn the ignition key OFF. Remove connector A from the EGR ECU. Measure the resistance between EGR ECU connector A pin 1 and a known good ground. If the measured resistance does NOT indicate acceptable continuity to ground, a problem exists between EGR ECU connector A and ground. Locate and repair the problem and retest the system.
5) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 52 and EGR ECU connector A pin 3. If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module and the EGR ECU.
6) Disconnect harness connector B from the Engine Management System (EMS) Module. Disconnect harness connector A from the EGR ECU. Measure the resistance between Engine Management System (EMS) Module
connector B pin 56 and EGR ECU connector A pin 6 . If the measured resistance does NOT indicate continuity, locate and repair the open circuit in the J1939 circuit between the Engine Management System (EMS) Module
and the EGR ECU.
7) Replace the EGR ECU and Mass Flow Sensor Assembly with a known good unit. Check the system for codes. If Code PID 412 is still set, reinstall the original EGR ECU and Mass Flow Sensor Assembly and replace the Engine
Management System (EMS) Module. Retest the system. If Code PID 412 is NOT set, replacing the EGR ECU and Mass Flow Sensor Assembly has corrected the problem.