Test Notes

NOTE: You should enter this pinpoint test only when a check for VREF has failed in the sensor pinpoint tests (D-series) or Pinpoint Test AA or QA.

This pinpoint test is intended to diagnose only the following:
- Sensor harness circuits: SIG RTN, VREF
- Three-wire sensors: TP, EVP, MAP
- Powertrain Control Module (PCM)

Reference Voltage (VREF) is a positive voltage (about 5.0 volts) that is output by the PCM. This consistent voltage is used by all three-wire sensors. Signal Return (SIG RTN) is a dedicated ground used by most sensors and some other inputs.