PACCAR MX (2004 Emissions) Fault Code: P1021 BPV Actuator – CAN Communication Error

PACCAR MX (2004 Emissions) Fault Code: P1021 BPV Actuator – CAN Communication Error

SET CONDITIONS:
The BPV valve (L096) detects that the cyclic CAN command message transmitted by the PCI ECU (D420) is missing for more than 7.5 seconds.

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

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive as soon as 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:
CAN wiring

ADDITIONAL INFORMATION:
1. The BPV valve (L096) is controlled by a cyclic CAN command message transmitted by the PCI ECU (D420) in which the operating mode and the target position are requested.
2. There is still CAN communication between the BPV actuator and PCI ECU with this fault active.
3. The actuator motor is switched off and the BPV valve is fully opened (100% position) with this fault active.
4. Engine torque is reduced after 10 hours of engine operation.