PACCAR PX-9 CM2350 (2013-17) Fault Code:1976 PID:SID 27 SPN:641 FMI:0 VGT Actuator Driver Temperature – Data Valid But Above Normal Operating Range – Least Severe Level

Description

Reason:
VGT Actuator Driver Over Temperature (Calculated) – Data Valid But Above Normal Operating Range – Least Severe Level. High internal VGT actuator temperature has been detected.

Effect:
None on performance.

Circuit Description:
The variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code.

Component Location:
The VGT actuator is located on the turbocharger bearing housing.

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 internal temperature of the Variable Geometry Turbocharger (VGT) actuator exceeded 125°C [257°F] continuously for 30 minutes.

Action Taken When the Fault Code is Active:
The ECM logs the fault code immediately when the diagnostic runs and fails.

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 Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults.

Shop Talk:
This fault code will be inactive when the vehicle is in the shop because the VGT actuator temperature has cooled down. Troubleshoot multiple inactive counts of this fault code as an active fault code. Also check for exhaust leaks blowing on the VGT actuator. Repair any external leaks.

Possible Causes:
1) Inactive fault codes
2) Bad VGT actuator coolant lines
3) Faulty ECM