DTC P1635: 5-Volt Reference 1 Circuit: Description
WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) uses the 5-volt reference 1 circuit as a sensor feed to the following sensors:
- The Throttle Position (TP) sensor.
- The Manifold Absolute Pressure (MAP) sensor.