It can be a simple fix or expensive depending on the source of the fault.
Here are diagnostic procedures for checking out the trouble code.
DTC P1632: THEFT DETERRENT SYSTEM FUEL DISABLE SIGNAL RECEIVED
Vehicle Theft Deterrent (VTD) system disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Control Module (BCM) and PCM.
When starting engine, PCM looks for a password from BCM through the Class II serial data circuit. If password is not recognized or not present, PCM will disable engine. There are 2 tamper detection modes: no password received and incorrect or disable password received (3 invalid passwords received).
DTC will set when an unrecognized or incorrect password sent to PCM from BCM or an undecided password sent from BCM.
1. Perform On-Board Diagnostic (OBD) system check. After performing OBD system check, go to next step.
2. Using scan tool, check if DTC P1626 or P1631 is also set. Diagnose affected DTC(s). If DTC P1626 or P1631 is not set, go to next step.
3. Perform password learn procedure. To perform learn procedure, attempt to start vehicle, then leave ignition on. The THEFT SYSTEM indicator light will flash for 4 seconds, then remain on for 10 minutes. Theft System Learn Mode will display DISABLED on scan tool. When THEFT SYSTEM indicator light turns off, go to next step
4. Turn ignition off. Repeat step 3 two more times. When THEFT SYSTEM indicator light turns off on the 3rd ignition cycle, and Theft System Learn Mode will display ENABLED on the scan tool, attempt to start vehicle. Once vehicle is running, the password is learned. Attempt to restart the engine, if engine starts and continue to run, see DIAGNOSTIC AIDS. If engine does not start or does not stay running, go to next step.
5. Using scan tool, display data list for BCM. If scan tool indicates that PassLock data is valid, go to next step. If scan tool does not indicate that Passlock data is valid, go to step 7.
6. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step
7. Check if any BCM or PassLock related DTCs are set. Diagnose affected DTCs. If no other DTCs are set, see DIAGNOSTIC AIDS.
8. Using scan tool, clear DTCs. Warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this DTC ran and passed, go to next step. If scan tool does not indicate that this DTC ran and passed, repeat step 2.
9. Check if additional DTC are set. Diagnose affected DTCs. If no other DTCs are set, system is okay.
Attempting to start vehicle by by-passing the theft deterrent system or substituting parts without performing the password learn procedure may set DTC. If no password is received, DTC U1064 and P1632 may set. PCM must be reflashed to allow new password to be learned if BCM is replaced.
An intermittent may be caused by poor connection, rubbed-through wire insulation or a broken wire inside insulation.