P1635 CHEVROLET - 5-Volt Reference Circuit Low Conditions
A/C Pressure sensor harness is open or shorted
MAP sensor harness is open or shorted
EGR valve harness is open or shorted
When is the code detected?
The P1635 code is set when the reference voltage from the sensor is our of range.
Engine Light ON (or Service Engine Soon Warning Light)
P1635 Chevrolet Description
The Powertrain Control Module (PCM
) uses a common 5.0 Volt Reference 1 circuit as a sensor feed. This circuit supplies 5 Volts to the following sensors: The Air Condition (A/C) Pressure sensor, the Manifold Absolute Pressure (MAP
) sensor, and the Engine Gas Recirculation (EGR
) valve. The PCM
monitors the voltage on the 5.0 Volt Reference 1 circuit.