DTC P1635: 5-Volt Reference 1 Circuit: Description
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 GMC Savana Special, 2002 GMC Savana Camper Special, and 2002 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) uses a common 5-volt reference 1 circuit as a sensor feed. This circuit supplies 5 volts to the following sensors:
- The Manifold Absolute Pressure (MAP) sensor.
- The Exhaust Gas Recirculation (EGR) valve.
The PCM monitors the voltage on the 5-volt reference 1 circuit. This DTC sets if the voltage is out of range.
This Diagnostic Trouble Code (DTC) sets if the 5-volt reference circuit is shorted to ground. When the 5-volt reference circuit or signal circuits are shorted to a voltage both DTC P1635 and DTC P1639 set. The following components or circuits need to be inspected:
- The MAP sensor.
- The EGR valve.
- The Throttle Position (TP) sensor.
- The fuel level sensor.
- The Fuel Tank Pressure (FTP) sensor.