Diesel Data: Automotive Repair

Test U: The O/D OFF Indicator Is Never/Always On

PINPOINT TEST U: THE O/D OFF INDICATOR IS NEVER/ALWAYS ON

Normal Operation
The instrument cluster (IC) receives the overdrive (O/D) off signal from the PCM over the high speed controller area network (HS-CAN) communication bus. When the O/D function is selected off, the PCM sends a message to the instrument cluster (IC) to illuminate the O/D off indicator. If the O/D on/off message is missing or if the data is deemed invalid by the instrument cluster (IC) for more than 5 seconds, the instrument cluster (IC) sets DTC U0101 in continuous memory and defaults the O/D off indicator off.

NOTE: If DTC U0101 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:
- O/D concern
- PCM
- Instrument cluster (IC)


U1-U2:






U3-U6: