P1630

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Vehicle Theft Deterrent (VTD) system, called a Passlock II(TM) system, is designed to prevent vehicle theft by disabling the engine unless the Passlock(TM) lock cylinder is correctly engaged by a mechanical key. The Passlock II(TM) System utilizes the four following components for theft detection:
^ The lock cylinder
^ The ignition switch
^ The Body Control Module (BCM)
^ The Powertrain Control Module (PCM)

When the ignition switch is first turned ON, the Body Control Module (BCM) will send a password to the PCM through the Class 2 serial data circuit. If the BCM 5 password does not match the password that is stored in the PCM, the PCM will disable the engine. This will cause the engine to start and stall immediately or to not start at all.

The SYSTEM telltale will flash on the IPC and the engine is disabled until a matching password is received. The password is checked every 4 seconds. The engine is disabled for at least 10 minutes and the SYSTEM telltale will flash on the IPC for approximately 4 seconds then will illuminate solid on the Instrument Panel Cluster (IPC) for the 10 minutes for the following passwords received:
^ Fuel disabled
^ Undecided
^ Mismatched

The following are four situations in which the PCM and BCM passwords would not match:
^ The PCM does not receive a password from the BCM - there is no communication between the BCM and PCM.
^ The BCM sends a Fuel Disabled password, indicating that a tamper has occurred.
^ The BCM sends an Undecided password.
^ The PCM receives a password from the BCM that does not match, or more than three invalid passwords other than Fuel Disabled or Undecided are received.

After the vehicle has passed theft detection, the PCM will continue a normal engine operation. If the PCM loses the BCM communication within the same ignition cycle, the vehicle will continue to run on the following ignition cycles. This mode is called the fail enable mode. Additional information can be found in the Theft Deterrent system of this document.

CONDITIONS FOR SETTING THE DTC
The PCM is ready to learn a new Passlock II(TM) password after the following conditions have occurred:
^ The PCM receives an incorrect password.
^ The PCM finishes the 10 minute learn pending timer, that is, the ignition is left ON for 10 minutes.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will record operating conditions at the time the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers.
^ A history DTC stores.

CONDITIONS FOR CLEARING THE MIL/DTC
^ As soon as one good, or matching, password is received at key-up, it becomes a history code. A good password is does not include a Fuel Disabled or Undecided password.
^ A history DTC will clear after 40 consecutive warm-up cycles without a fault.
^ Use a scan tool to clear the DTCs.

DIAGNOSTIC AIDS
Attempting to start the vehicle by bypassing the Passlock II(TM) system or by substituting parts without performing the password learn procedure may set a DTC P1631 and a P1632.

If no password is received, a DTC U1064 and P1632 may be set.

An intermittent may be caused by the following conditions:
^ A faulty electrical terminal connection
^ A broken wire inside the insulation

Thoroughly inspect any suspected circuitry for the following items:
^ Backed-out terminals or improper mating
^ Improperly formed or damaged terminals
^ Faulty terminal-to-wire connections
^ Physical damage to the wiring harness
^ Corrosion Test Description

The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On-Board Diagnostic (OBD) System Check prompts the technician to complete some basic diagnostics and to store the Freeze Frame and Failure Records data on the scan tool, if applicable. This creates an electronic copy of the data that was taken when the malfunction occurred. The information is then stored in the scan tool for later reference.
7. This DTC is normally set and cleared during a password learn procedure. If the password learn procedure is not completed, this DTC will not be cleared.
9. Replacement PCMs must be reprogrammed. A reprogrammed PCM does not require the password learn procedure to be performed. The password will be learned on the first ignition cycle. Refer to the latest Techline(TM) information for programming procedures. The replacement PCM must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline(TM) procedures for PCM reprogramming and for the Crankshaft Position Variation Learn Procedure.
11. If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.