P1632

DTC P1632

CIRCUIT DESCRIPTION
The theft deterrent control module sends the start enable password to the engine control module (ECM) via the serial data circuit. The ECM verifies the start enable password received matches the password stored in memory. If the start enable password is correct, the ECM enables the starting and fuel delivery systems. If a start disable message is received, the vehicles starting and fuel delivery systems will be disabled, the vehicle not allowed to start, and DTC P1632 will be set.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P1632 Theft Deterrent Start Disable Signal Received

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
The ECM receives a start disable message from the theft deterrent module (TDM).

ACTIONS TAKEN WHEN THE DTC SETS
- The vehicle will not start.
- The instrument panel cluster (IPC) will illuminate the SECURITY indicator.
- The ECM will not illuminate the malfunction indicator lamp (MIL).

CONDITIONS FOR CLEARING THE MIL/DTC
- A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
- The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
A GM SPO replacement ECM is in a functional state to learn the password from the theft deterrent control module. If the theft deterrent control module is replaced, the ECM must be placed in password learning mode to relearn the new password. Once learned, the password becomes permanent information that remains in the ECM. The loss of ECM battery or ignition voltage does not affect the programmed password information. Refer to Programming Theft Deterrent System Components.

TEST DESCRIPTION

Step 1 - Step 6:

The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that no other theft deterrent DTCs are set, which should be diagnosed before proceeding with these diagnostics.
3. To set this code, the password that the ECM has received a message from the theft deterrent, indicates some fault is present and vehicle starting should not be allowed. This condition can occur if the theft deterrent control module has been replaced and the Programming Theft Deterrent System Components procedure has not been performed.
5. If the ECM resets the DTC after the programming theft deterrent system components procedure has been performed, the theft deterrent module is malfunctioning.