B: Reference Voltage Introduction

B: Pinpoint Tests

Note

You should enter this pinpoint test only when a check for VREF has failed in the sensor pinpoint tests for the AP, MAP, BARO, ICP, EBP or CMP 3-wire sensors.

Remember

This pinpoint test is intended to diagnose only the following:

• sensor harness circuits: SIG RTN, VREF
• 3-wire sensors: AP, MAP, BARO, ICP, EBP, CMP
• powertrain control module (PCM) (12A650)

Description

Reference Voltage (VREF) is a positive voltage (approximately 5.0 volts ± 3%) that is output by the powertrain control module (PCM). This consistent voltage is used by all 3-wire sensors.

Signal Return (SIG RTN) is a dedicated ground used by most sensors and some other inputs.

Pinpoint Test Schematic

B: Pinpoint Tests