Circuit Description

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

• The air conditioning (A/C) pressure sensor
• The throttle position (TP) sensor 1
• The accelerator pedal position (APP) sensor 1
• The fuel tank pressure (FTP) sensor

The ECM monitors the voltage on the 5-volt reference circuit. If the voltage is out of tolerance, the ECM will set DTC P0641.