P1634

Diagnostic Chart:

Engine Controls Schematics: PCM Power and Grounds:

CIRCUIT DESCRIPTION
The PCM receives three ignition inputs from the ignition switch: IGN 0, IGN 1, and CRANK Request. The PCM receives the IGN 1 input with the ignition switch in RUN and START. The PCM uses a class 2 ignition mode message, and the voltage input from two separate systems to test the IGN 1 circuit. If the PCM detects an improper IGN 1 input, DTC P1634 will set.

CONDITIONS FOR RUNNING THE DTC
No Class 2 serial data circuit problem.

CONDITIONS FOR SETTING THE DTC
The PCM detects an improper IGN 1 input.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Fail Records information only.

CONDITIONS FOR CLEARING THE DTC
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.