Circuit Description

The powertrain control module (PCM) uses the 5-volt reference circuit as a sensor feed to the following sensors:

• The boost sensor.
• The crankshaft position (CKP) sensor.
• The optical/fuel temperature sensor (CMP/High resolution).

The ECM monitors the voltage on the 5-volt reference circuit. If the voltage is out of tolerance, the ECM will set DTC P1635.