Paccar

PACCAR MX (2004 Emissions) Fault Code: P1722 BPV Control – Data Erratic, Intermittent, or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the actual BPV valve position measured by the BPV valve actuator differs too much from the commanded position (by the PCI ECU) for more than 40 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Sticking or blocked BPV valve or mechanism

ADDITIONAL INFORMATION:
The BPV valve is supposed to create back pressure in the engine exhaust system and control exhaust gas mass flow. During normal engine control, the BPV valve position is commanded by the PCI ECU. The actual control of the valve is carried out by the actuator on the BPV valve (L096), a smart actuator that communicates with the PCI ECU via ECAN. The actuator provides feedback to the PCI ECU about the valve position.

PACCAR MX (2004 Emissions) Fault Code: P1723 Exhaust Gas Pressure Before Turbine – Data Valid but Too Low

SET CONDITIONS:
The PCI ECU (D420) detects that measured pressure before turbine is lower than the requested pressure before turbine for more than 40 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the engine speed is above 600 rpm and
2. When the engine is running at a steady load and
3. The [engine mode] is SCR HEATING, SCR HIGH EFFICIENCY, STANDARD or PROTECTION

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to INACTIVE when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The end-stops of the VTG turbocharger actuator programmed incorrectly

IMPORTANT: Turbocharger actuators are occasionally recalibrated by a technician in an attempt to solve VTG turbocharger actuator position-related DTCs. By doing so, the actuator is mistakenly calibrated to a smaller span than the initial maximum span of the turbocharger mechanism. In that case the requested pressure before turbine cannot be reached, resulting in DTC P1723.

2. Leaking exhaust system
3. Leaking pressure sensor before turbine tube
4. Plugged pressure sensor before turbine tube
5. Pressure sensor before turbine deviation

ADDITIONAL INFORMATION:
1. The PCI ECU uses the pressure before turbine for, among other things, controlling the VTG turbocharger, EGR valve position, BPV valve position and engine braking.

2. The pressure before turbine is measured by the pressure sensor before turbine (F826).

PACCAR MX (2004 Emissions) Fault Code: P1724 Exhaust Gas Pressure Before Turbine – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that measured pressure before turbine is higher than the requested pressure before turbine for more than 40 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running at a steady load.

CORRESPONDING OBD READINESS MONITOR:
VTG monitor

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the following conditions:
– Corresponding readiness monitor displays ‘Ready’
– Diagnostic conditions are met
– Set conditions are met
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Restriction in EGR circuit
2. Restriction in exhaust system
3. Pressure sensor before turbine deviation
4. Incorrect calibration of the VTG turbocharger actuator
5. Mechanical defect of the VTG turbocharger actuator (internal bearing wear)

ADDITIONAL INFORMATION:
1. The PCI ECU uses pressure before turbine:
– To make EGR gas flow toward the inlet possible
– To generate boost pressure
– For engine braking
2. The pressure before turbine is measured by the pressure sensor before turbine (F826).

PACCAR MX (2004 Emissions) Fault Code: P1726 Exhaust Gas Pressure Before Turbine – Response Too Slow, On Requested Pressure

SET CONDITIONS:
The PCI ECU (D420) detects a too slow response of the requested pressure before turbine value.

DIAGNOSTIC CONDITION:
MX-11:
This diagnostic runs when the engine is running in engine mode ‘SCR heating’ or ‘SCR super high efficiency’ and the engine speed is more than 1000rpm during normal engine load conditions.

MX-13:
This diagnostic runs when the engine is running in engine mode ‘SCR super high efficiency’ and the engine speed is more than 1000rpm during normal engine load conditions.’

CORRESPONDING OBD READINESS MONITOR:
VTG monitor

RESET CONDITION:
This DTC will change to inactive after the ignition is keyed off and on again and the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the following conditions:
– Corresponding readiness monitor displays ‘Ready’
– Diagnostic conditions are met
– Set conditions are met
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Exhaust gas leakage
2. Incorrectly calibrated VTG turbocharger actuator
3. Plugging of the pressure sensor before turbine pipe
4. Leaking BPV valve
5. Leaking EGR valve
6. Faulty VTG turbocharger nozzle ring mechanism or actuator
7. Faulty pressure sensor before turbine

ADDITIONAL INFORMATION:
1. The pressure before turbine is an input value for the engine management system and is used for control of the VTG, BPV valve and EGR valve.
2. The pressure is measured by the pressure sensor before turbine (F826).
3. This DTC is used to check the response time of the VTG, BPV and EGR valves based on the measured pressure before turbine.
4. DTC P1726 is an OBD fault. The corresponding OBD readiness monitor changes to ready once the diagnostics have run.

IMPORTANT: In an attempt the solve VTG turbocharger actuator position related DTCs, turbocharger actuators are occasionally recalibrated by the technician. By doing so, the actuator can be mistakenly calibrated to a smaller span than the initial maximum span of the turbocharger mechanism. In that case, the expected pressure before turbine is not reached during engine load situations, resulting in DTC P1726.

PACCAR MX (2004 Emissions) Fault Code: P1727 VTG Turbocharger Control – Data Erratic, Intermittent or Incorrect

IMPORTANT: This DTC can be the result of communication issues on the E-CAN network. If one of the following CAN-related DTCs is present in the DTC history, DO NOT TROUBLESHOOT this DTC:
U1011
U104C
U1159
U1835

SET CONDITIONS:
The PCI ECU (D420) detects that the actual VTG turbocharger nozzle ring position differs too much from the commanded position (by the PCI ECU) for more than 40 s.

DIAGNOSTIC CONDITION:
This diagnosis runs when:
1. The engine is running at a steady speed and load.
2. The engine mode is SCR high efficiency, Standard or Protection.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to INACTIVE after the diagnosis runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
IMPORTANT: DO NOT re-calibrate the turbocharger actuator before the cause of this DTC has been identified and solved. Re-calibration could lead to engine performance and/or engine brake performance issues.

1. Communication issues between PCI and VTG turbocharger actuator. (In that case, the PCI ECU sends request for specific nozzle ring position, but turbocharger actuator does not respond with actual nozzle ring position).
2. Temporary blockage of the VTG turbocharger nozzle ring mechanism due to:
– Soot build-up
– Freezing
– Engine start shortly after a hot shutdown
3. Turbocharger actuator calibration procedure was not completed successfully.
4. Malfunction turbocharger actuator
5. Malfunction VTG turbocharger nozzle ring mechanism

ADDITIONAL INFORMATION:
1. To create the requested boost pressure and exhaust gas pressure, the exhaust gas flow guidance into the turbine rotor is controlled by the position of the turbocharger nozzle ring.
2. During normal engine control the turbocharger nozzle ring position is commanded by the PCI ECU.
3. The actual control of the nozzle ring is carried out by the VTG turbocharger actuator (L037), a smart actuator that communicates with the PCI ECU via ECAN.
4. The actuator provides feedback to the PCI ECU about the nozzle ring position.
5. This DTC can become active together with P2563.

PACCAR MX (2004 Emissions) Fault Code: P1751 Malfunction Indicator Lamp (MIL) – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (B23)

SET CONDITIONS
This DTC is set when the ECU detects a higher voltage than expected on the signal or control circuit of the ECU.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring has a short circuit to supply.
2. A malfunction of the sensor or actuator

PACCAR MX (2004 Emissions) Fault Code: P1863 CAN Communication – Message (PROPB_AST) Out of Range, Maneuvering Mode From Transmission System

SET CONDITIONS:
This DTC is set when a CAN message is received correctly but the content (signal value or status) is out of the expected range.

DIAGNOSTIC CONDITION:
The diagnostic runs continuously when the ignition is keyed on or when the engine is running.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. A corrupt or empty CAN message
2. A malfunction in the system from which the message originates

ADDITIONAL INFORMATION:
1. A ‘message out of range’ DTC is activated by the receiving ECU but indicates a malfunction within another system which communicates with this ECU.
2. The cause of the DTC must be sought in the system from which it originates.

Example:
1. [ECU 1] detects an incorrect or missing signal from [sensor A].
2. [ECU 1] sets [DTC 1] (In this specific case, an open circuit DTC).
3. [ECU 1] constantly informs [ECU 2] about the status of [sensor A] via CAN messages.
4. Since the data received from the sensor is not available or not plausible, an ’empty’ CAN message is sent from [ECU 1] to [ECU 2].
5. [ECU 2] interprets the empty message as being out of the expected range and sets the ‘out of range DTC’ [DTC 2].

PACCAR MX (2004 Emissions) Fault Code: P1866 Exhaust Gas Pressure Before Turbine – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the pressure before turbine is more than 9 bar.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to INACTIVE when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Clogging tube of the pressure sensor before turbine
2. Pressure sensor before turbine deviation
3. Malfunction of the VTG turbocharger or turbocharger actuator

PACCAR MX (2004 Emissions) Fault Code: P1867 Exhaust Gas Temperature After BPV – Data Valid but Too High

CORRESPONDING OBD READINESS MONITOR:
None

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful