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Reason:
Engine Crankshaft Speed/Position – Data Erratic, Intermittent, or Incorrect. Crankshaft engine speed sensor intermittent synchronization.

Effect:
Possible reduced engine performance.

Circuit Description:
The crankshaft position and camshaft position sensors are Hall effect type sensors. The engine control module (ECM) provides a 5 volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the dimples in the back of the camshaft gear move past the position sensor, a signal is generated on the position sensor signal circuit.

The ECM interprets this signal and converts it to an engine speed. A missing tooth on the crankshaft gear is used by the ECM to determine the position of the engine.

Component Location:
The crankshaft position and camshaft position sensor location varies, depending on engine model.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine speed is greater than 1200 RPM.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected an intermittent or degraded signal from the crankshaft speed/position sensor over an extended period of engine operation

Action Taken When the Fault Code is Active:
1) The ECM logs the fault code immediately when the diagnostic runs and fails.
2) For On-Board Diagnostics (OBD) engines, the ECM illuminates the the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
3) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
4) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and run it at high idle for 5 minutes.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
During engine operation, the ECM monitors the primary speed sensor (crankshaft speed sensor) signal. Fault Code 689 will become active and light the yellow lamp if the signal from the primary speed sensor is not present or degraded for more than 3 continuous seconds.

Meanwhile, if the primary engine speed sensor signal is not present or is degraded for a moment (less than 3 seconds), the ECM will interrupt injection events based on the primary engine speed sensor and resume injection events using the backup engine speed sensor.

Engine power will be reduced while the injection events are based on the backup speed sensor. If the primary speed sensor signal returns, the ECM will automatically interrupt injection events based on the backup speed sensor and resume injection events based on the primary speed sensor. If over a period of time, the ECM detects several incidents of a loss of the primary speed sensor signal, this fault code will become active.

A vehicle operator can notice an intermittent “misfire” if the injection events are interrupted while the ECM switches from control based on the primary and secondary speed sensors. Also, a vehicle operator can notice intermittent “low power” if a “glitch” in the primary speed sensor signal causes the engine to intermittently use the backup speed sensor for injection control.

This fault code becomes active whenever the ECM detects a persistent loss of the primary engine speed sensor signal over a short period of time. This fault becomes inactive if the ECM does not detect a loss of the primary engine speed sensor signal for at least 20 minutes.

Possible causes of this fault code include:
1) Intermittent loss of primary speed sensor signal; the most likely cause is an intermittent open or short circuit that can be experienced with speed sensor connector problems.
2) Sensor air gap that is marginally too small or too large.

Actions to take if this fault is intermittent:
1) Look for intermittent engine harness connections in the primary engine speed sensor circuit.
2) Look for loose connections at the ECM connector where the pins can not be locked into the socket.
3) Look for places where the engine harness has worn into a nearby component, causing an intermittent short circuit.
4) Look for pin wear at the speed sensor.
5) Inspect the target wheel for damage

Reason:
Engine Camshaft Speed/Position Sensor – Data Erratic, Intermittent, or Incorrect. Camshaft engine speed sensor intermittent synchronization.

Effect:
None on performance.

Circuit Description:
The engine control module (ECM) provides a 5 volt supply to the engine camshaft speed/position sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The camshaft speed/position sensor provides a signal to the ECM on the camshaft speed/position sensor signal circuit. This sensor generates a signal to the ECM as the camshaft speed indicator lobe moves past the sensor. The ECM interprets this signal into an engine speed reading and determines engine position. This sensor is used as a backup sensor if the primary engine crankshaft speed/position signal is lost.

Component Location:
The camshaft position sensor is located in the top of the gear housing on the exhaust side.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine speed is greater than 1200 RPM.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected an intermittent loss of the camshaft speed/position sensor signal.

Shop Talk:
During engine operation, the ECM monitors the secondary speed sensor (camshaft speed sensor) signal. Fault Code 778 will become active and light the yellow lamp if the signal from the secondary speed sensor is not present or degraded for more than 3 continuous seconds. If over a period of time the ECM detects several incidents of a loss of the secondary speed sensor signal, but the signal loss is short in duration, this fault code will become active. Since the secondary engine speed signal is not used for normal engine operation, a vehicle operator should not notice any symptoms related to this problem. This fault code becomes active whenever the ECM detects a persistent loss of the secondary engine speed sensor signal over a short period of time.

This fault becomes inactive if the ECM does not detect a loss of the secondary engine speed sensor signal for at least 20 minutes.

Problems that can cause this fault:
1) Intermittent loss of primary speed sensor signal; the most likely cause is an intermittent open or short circuit that can be experienced with speed sensor connector problems.
2) Sensor air gap that is marginally too small or too large, or target wheel exhibits excessive runout.

Actions to take if this fault is intermittent:
1) Look for intermittent engine harness connections in the secondary engine speed sensor circuit
2) Look for loose connections at the ECM connector where the pins can not be locked into the socket
3) Look for places where the engine harness has worn into a nearby component, causing an intermittent short circuit
4) Look for pin wear at the speed sensor
5) Inspect the target wheel for damage

Reason:
Engine Crankshaft Speed/Position – Data Valid But Above Normal Operational Range – Most Severe Level. Engine speed signal indicates engine speed above engine protection limit.

Effect:
Possible reduced engine performance.

Circuit Description:
The crankshaft position and camshaft position sensors are Hall effect type sensors. The engine control module (ECM) provides a 5 volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the dimples in the back of the camshaft gear move past the position sensor, a signal is generated on the position sensor signal circuit. The ECM interprets this signal and converts it to an engine speed. A missing tooth on the crankshaft gear is used by the ECM to determine the position of the engine.

Component Location:
The crankshaft position and camshaft position sensor location varies, depending on engine model.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the engine speed had exceeded the calibration limit.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.
2) Fueling to the engine is stopped until the engine speed drops to normal operating speeds.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
4) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
If Fault Code 234 becomes active only during engine braking, and the engine brakes fail to engage, check for a short circuit to ground in the engine brake wiring harness. The rocker lever cover must be removed to perform this inspection. Repair or replace the engine brake wiring harness as necessary.

Possible Causes:
1) External fuel sources drawn into the intake air passage
2) Reverse powering (motoring) of the engine
3) Tampering of the engine speed/position sensors.
4) Inspect the intake manifold for sources of flammable vapors. Check the turbocharger seals to verify there are no oil leaks. Inspect the engine speed/position sensors for damage or tampering.

Reason:
Turbocharger Turbine Intake Temperature – Data Valid But Above Normal Operating Range – Least Severe Level. Turbocharger turbine intake temperature has exceeded the engine protection limit.

Effect:
Possible reduced engine performance.

Circuit Description:
The exhaust gas temperature is calculated by the engine control module (ECM). The exhaust gas temperature is derived by the ECM, based on engine operating conditions such as intake manifold air temperature, engine speed, injection timing, intake manifold pressure, and fuel flow.

Component Location:
There is not a physical exhaust gas temperature sensor in the system. The exhaust gas temperature is a calculation of exhaust gas temperature before the turbocharger, and is also known as turbine intake temperature.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) calculated the turbine intake temperature was greater than a calibratible value.

Action Taken When the Fault Code is Active:
1) The ECM logs the fault code immediately when the diagnostic runs and fails.
2) Fuel is limited in an attempt to decrease the temperature of the exhaust gas entering the turbocharger.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
3) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
This fault code is an information fault code, indicating that the engine has been derated for high turbine intake temperature (exhaust temperature). No troubleshooting is necessary for this fault code. It is only an indicator that the engine power was derated to limit the exhaust temperature. If the condition continues to exist, Fault Code 2451 will become active.

Possible Causes:
1) Inactive fault codes
2) Faulty ECM

Reason:
Turbocharger Turbine Intake Temperature – Data Valid But Above Normal Operating Range – Least Severe Level. Turbocharger turbine intake temperature has exceeded the engine protection limit.

Effect:
Possible reduced engine performance.

Circuit Description:
The exhaust gas temperature is calculated by the engine control module (ECM). The exhaust gas temperature is derived by the ECM, based on engine operating conditions such as intake manifold air temperature, engine speed, injection timing, intake manifold pressure, and fuel flow.

Component Location:
There is not a physical exhaust gas temperature sensor in the system. The exhaust gas temperature is a calculation of exhaust gas temperature before the turbocharger, and is also known as turbine intake temperature.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) calculated the turbine intake temperature was greater than a calibratible value.

Action Taken When the Fault Code is Active:
1) The ECM logs the fault code immediately when the diagnostic runs and fails.
2) Fuel is limited in an attempt to decrease the temperature of the exhaust gas entering the turbocharger.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
3) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
This fault code is an information fault code, indicating that the engine has been derated for high turbine intake temperature (exhaust temperature). No troubleshooting is necessary for this fault code. It is only an indicator that the engine power was derated to limit the exhaust temperature. If the condition continues to exist, Fault Code 2451 will become active.

Possible Causes:
1) Inactive fault codes
2) Faulty ECM

Reason:
EGR Valve Control Circuit – Current Below Normal or Open Circuit. Motor terminal or motor coil open circuit has been detected by the ECM.

Effect:
Possible reduced engine performance.

Circuit Description:
The exhaust gas recirculation (EGR) valve is controlled by a brushless motor located on top of the EGR valve. The EGR valve motor uses three different motor legs to move the valve through its range of motion. The ECM uses the EGR motor A, B, and C wires to command the EGR valve to the appropriate position in order to meet EGR flow targets.The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires. The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires.

Component Location:
The EGR Valve and EGR Differential Pressure Sensor location varies depending on engine model.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected an open circuit in the engine wiring harness or EGR valve motor coil.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
3) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
N/A

Possible Causes:
1) EGR motor circuit open circuit
2) Open circuit in the wiring harness
3) Malfunctioning ECM

Reason:
Coolant Level – Data Valid But Below Normal Operating Range – Most Severe Level. The engine coolant is severely low

Effect:
Progressive power and/or speed derate increasing in severity from time of alert. If the Engine Protection Shutdown feature is enabled, the engine will shut down 30 seconds after the red STOP lamps starts flashing.

Circuit Description:
The coolant level sensor is a switch and is used to measure the level of the engine coolant in the radiator top tank. The coolant level sensor is immersed in the coolant and returns a different signal voltage when immersed in coolant versus being out of coolant. The engine control module (ECM) monitors the change in the signal voltage to determine the level of the engine coolant.

Component Location:
The engine coolant level sensor is typically located in the radiator top tank or surge tank. Refer to the OEM service manual for the location.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the coolant level sensor signal voltage was greater than 3-VDC for more than 30 seconds, indicating severely low coolant level.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.
2) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
3) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.
4) The engine will be shut down if the Engine Protection Shutdown feature is enabled.

Conditions for Clearing the Fault Code:
1) To validate the repair, start the engine and let it idle for up to 5 minutes.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
4) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
Possible Causes:
1) Low coolant level

Reason:
EGR Valve Control Circuit – Current Above Normal or Grounded Circuit. A short circuit to ground has been detected in the EGR valve motor circuit.

Effect:
Possible reduced engine performance

Circuit Description:
The exhaust gas recirculation (EGR) valve is controlled by a brushless motor located on top of the EGR valve. The EGR valve motor uses three different motor legs to move the valve through its range of motion. The ECM uses the EGR motor A, B, and C wires to command the EGR valve to the appropriate position in order to meet EGR flow targets.The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires. The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires.

Component Location:
The EGR Valve and EGR Differential Pressure Sensor location varies depending on engine model.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position and the engine is running

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected a short circuit to ground in the EGR motor supply circuits.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
3) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
N/A

Possible Causes:
1) One of the EGR motor circuits shorted to ground in the EGR valve motor
2) One of the EGR motor circuits shorted to ground in the harness
3) Malfunctioning ECM.

Reason:
EGR Valve Control Circuit – Mechanical System Not Responding or Out of Adjustment. The EGR valve motor has exceeded the duty cycle limit, indicating a stuck open EGR valve.

Effect:
EGR valve actuation will be disabled.

Circuit Description:
The exhaust gas recirculation (EGR) valve is controlled by a brushless motor located on top of the EGR valve. The EGR valve motor uses three different motor legs to move the valve through its range of motion. The ECM uses the EGR motor A, B, and C wires to command the EGR valve to the appropriate position in order to meet EGR flow targets.The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires.

Component Location:
The EGR valve location can vary, depending on engine application.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the duty cycle required to open the EGR valve was greater than 95 percent for 3 seconds. The fault code is triggered after two failed attempts. The fault code will be inactive at key ON. It will only go active if the EGR valved is commanded open and the EGR valve is unable to move to the commanded position.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
2) Active and stationary regeneration of the diesel particulate filter will be disabled.
3) Exhaust Gas Recirculation (EGR) valve operation will be disabled.
4) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, start the engine and let it idle for 1 minute.
2) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
3) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
4) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults.

Shop Talk:
This fault code is triggered when the EGR valve motor is unable to move the EGR valve in the open position. This is normally caused by a restriction in the EGR valve not allowing the EGR valve to move to the commanded position. The aftertreatment system must be inspected after making the appropriate repair outlined in this fault code troubleshooting tree. Progressive damage to the aftertreatment system may have occurred. Perform the aftertreatment initial check procedure to test for a damaged diesel particulate filter.

Possible Causes:
1) Inactive fault codes
2) Faulty engine harness and EGR valve connector pins
3) Faulty ECM