DTC P1635: 5-Volt Reference 1 Circuit: Description
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. 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.