P1635

Steps 1 - 4:

DTC P1635 5 Volt Reference Voltage Circuit Malfunction




Circuit Description
The Powertrain Control Module (PCM) monitors the 5 volt reference signal when the Ignition is ON. If the PCM senses the 5 volt reference signal circuit is above 5.12 volts or below 4.88 volts, then DTC P1635 will set. DTC P1635 is a type A code.

Conditions for Setting the DTC
- Ignition voltage is greater than 6.3 volts.
- Engine is running.
The above mentioned conditions are met and one of the following two conditions are met for 5 seconds within a 10 second test sample:
- PCM senses the 5 volt reference signal circuit is above 5.12 volts.
OR
- PCM senses the 5 volt reference signal circuit is below 4.88 volts.

Action Taken When the DTC Sets
- The PCM will illuminate the Malfunction Indicator Lamp (MIL) the first time the fault is detected.
- The PCM will store the conditions that were present when the DTC was set as Freeze Frame and in Failure Records.

Conditions for Clearing the MIL/DTC
- The PCM will turn OFF the MIL on the third consecutive trip without a reported failure.
- A History DTC will clear after 40 consecutive trips without a reported failure. The DTC can be cleared using the Scan Tool's "Clear Info" function.

Diagnostic Aids
Poor connections, or a damaged harness - Inspect the harness connectors for: backed-out terminals, improper mating or damaged terminals. Also, check for open circuits, shorts to ground, and shorts to voltage.