DTC P1635: 5-Volt Reference 1 Circuit: Description

The PCM uses the 5-volt reference 1 circuit as a sensor feed to the following sensors:

• The TP sensor.
• The MAP sensor.
• The EGR valve pintle position sensor.
• The Fuel Tank Pressure (FTP) sensor.

The PCM monitors the voltage on the 5-volt reference 1 circuit. If the voltage is out of tolerance, the PCM will set DTC P1635.