P1632 - FAULT CODE - OBD2

P1632 BUICK, CADILLAC, CHEVROLET, GMC, PONTIAC, SATURN: THEFT DETERRENT START DISABLE SIGNAL RECEIVED

The Immobilizer Module or Vehicle Theft Deterrent Module (VTD) sends the password to enable the ignition to the Engine Control Module (ECM) via a serial data circuit. After the password is received, the ECM challenges the password and works with the immobilizer controller to perform a calculation on the challenge. If the calculated response from the immobilizer module is equal to the ECM‘s calculation, the ECM will allow the vehicle’s engine to start. On the other hand, if the enable password is invalid, there will not be communication with the immobilizer module or a fuel disable password will be sent from the immobilizer, the ECM will disable the vehicle starting.

The setting of the P1632 OBDII diagnostic code is carried out when the calculated response of the immobilizer module does not match the calculation performed by the ECM.

• Check Engine light ON
• Activation of the anti-theft system.
• Impossible to start the engine.

Reasons to set the P1632 OBD2 fault code:

• The electrical circuits related to the security and theft prevention system may have damage to the wiring or connectors.
• The various components of the Anti-Theft Immobiliser System may be faulty.
• Motor Control Module may have bad electrical connections.
• The ECM may be faulty.

To troubleshoot the DTC P1632 OBDII, try this:

• See Technical Service Bulletins.
• Check for other immobilizer faults related to If so, perform the respective diagnosis.
• Check all the electrical components related to the immobilizer, security system, and ECM. Repair any damage to these.
• Check the integrity of the ECM, it is necessary to find specialists in the area because of the complexity of this diagnosis. If you determine damage to this controller, make the appropriate corrections.