Pinpoint Test AP: Auxiliary Powertrain Control System: Description
Perform this test only when directed here by QUICK TEST or if no DTCs are present and Auxiliary Powertrain Control Module (APCM) does not control engine RPM. Auxiliary powertrain control system provides an operator interface to the drive-by-wire powertrain control system to effect charge protection, RPM control and manual throttle control between 1300-2500 RPM. This test is intended to diagnose:
- Wiring harness circuits (KEY PWR, GND, BUS (+), BUS (-) and hi-mount brakelight).
- Auxiliary Powertrain Control Module (APCM).
- Enabling Conditions
Parking brake set, transmission in Park (A/T) or Neutral (M/T) and clutch pedal released. Service brake, accelerator pedal and brakelights must be functional. To operate system with hazard flashers, hi-mount brakelight circuit must be complete and operational.
Error DTCs are displayed from APCM only. See Fig 1. Identify DTC and perform appropriate procedure or test step:
- If APCM is inoperative at all times, go to step 1).
- If APCM is inoperative with hazard flashers for all vehicles except Econoline Cutaway, go to step 7).
- If APCM is inoperative with hazard flashers for Econoline Cutaway only, go to step 11).
- If APCM DTC CErr or CrSD is displayed, go to step 5).
- If APCM DTC EErr or AErr is displayed, replace APCM.