P1634

DTC P1634

CIRCUIT DESCRIPTION
The powertrain control module (PCM) receives the following ignition inputs from the ignition switch:
^ The ignition 0 signal
^ The ignition 1 signal
^ The crank signal

The PCM uses a class 2 Ignition mode message and the voltage input from 2 separate systems to test the ignition 1 circuit. If the PCM detects an improper ignition 1 signal, DTC P1634 will set.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P1634 Ignition 1 Switch Circuit

CONDITIONS FOR RUNNING THE DTC
There is no class 2 serial data circuit condition.

CONDITIONS FOR SETTING THE DTC
The ignition 1 signal is present, but the ignition 0 signal is not.

ACTION TAKEN WHEN THE DTC SETS
^ The control module stores the DTC information into memory when the diagnostic runs and fails.
^ The malfunction indicator lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
^ A current DTC Last Test Failed clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
^ Clear the DTC with a scan tool.

TEST

Steps 1 - 10: