PACCAR PX-9 CM2350 (2013-17) Fault Code:1939 PID:SID 212 SPN:3597 FMI:3 ECU Power Output Supply Voltage 1 – Voltage Above Normal or Shorted to High Source

Reason:
ECU Power Output Supply Voltage 1 – Voltage Above Normal or Shorted to High Source. High battery voltage detected by the variable geometry turbocharger actuator.

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 immediately after the keyswitch is turned OFF.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected battery voltage on the variable geometry turbocharger actuator circuit after the keyswitch is turned OFF.

Action Taken When the Fault Code is Active:
The ECM illuminates the amber CHECK ENGINE lamp 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 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 logged when the voltage to the variable geometry turbocharger actuator voltage is greater than or equal to battery voltage at key OFF. The variable geometry turbocharger will still continue to respond to commands from the primary engine ECM.

Possible Causes:
1) Inactive fault codes
2) Faulty engine harness and VGT actuator connector pins
2) Bad power supply and return circuit
3) Faulty ECM