Electronic Control System Signature, ISX and QSX15 Engines – FAULT CODE 475

Electronic Air Compressor Governor Circuit


Fault Code: 475
PID: S089
SPN: 1351
FMI: 4/4
LAMP: Yellow

Low voltage was detected on the electronic air compressor circuit when high voltage was expected.

Air compressor will not shut off.

Electronic Air Compressor Governor Circuit

Circuit Description

The electronic air compressor governor is a device used by the electronic control module (ECM) to control output of the air compressor.

Component Location

The electronic air compressor governor is located on the top of the air compressor.

Shop Talk

  • Inspect the engine block to chassis ground wire to make sure it is securely fastened to a clean, dry, conductive surface.
  • Check the starter solenoid positive (+) terminal for a loose connector or accessory wiring with damaged insulation.
  • Low voltage can be caused by short circuit to ground, a short circuit to another wire in the harness, or a shorted solenoid coil.
  • Voltage is required at the electronic air compressor governor to turn the compressor off. No voltage turns the compressor on.

Refer to Troubleshooting Fault Code t05-475.

Last Modified:  26-Oct-2010