Diagnostic System Check - Theft Deterrent Domestic
Circuit Description
The Passlock system is designed to prevent engine operation if the correct key is not used to start the vehicle. The ignition key turns the lock cylinder, cylinder rotation produces an analog voltage code in the Passlock sensor.
The Passlock module receives this voltage code and is compared to the last learned voltage code. If the codes match, the Passlock module sends a class 2 message to the VCM/PCM, enabling the fuel injectors.
Diagnostic Aids
You must perform the Diagnsotic System Check prior to diagnosing any symptom or any Diagnostic Trouble Code table. Diagnose the DTCs in the order specified in the Passlock System "Displaying Diagnostic Trouble Codes" list. Failure to do so may result in the following conditions:
| • | Extended diagnostic time |
| • | Incorrect diagnosis |
| • | Incorrect parts replacement |
If a Passlock module, a passlock sensor, or the VCM/PCM have been replaced, perform the learn procedure before following the Diagnostic System Check.
Important: On vehicles equipped with diesel engines, if you are instructed in any Theft Deterrent System test to start the vehicle you must always wait for the "Wait to Start" indicator to distinguish prior to cranking the engine. This process could take anywhere from 2 to 17 seconds.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Connect a scan tool to the data link connector. Can the scan tool be powered up? | -- | Go to Step 2 | Go to Step 6 | ||||||||
2 | Turn the ignition switch to the LOCK position. Is the SECURITY telltale on? | -- | Go to Step 3 | |||||||||
3 |
Did the SECURITY telltale turn on? | -- | Go to Step 4 | |||||||||
4 | Did the SECURITY telltale turn on and remain on for more than 6 seconds? | -- | Go to Step 7 | Go to Step 5 | ||||||||
5 | Does the SECURITY telltale flash? | -- | Go to Step 7 | Go to Step 9 | ||||||||
6 | Refer to Data Link Communications System Check in Data Link Communications. Is the repair complete? | -- | Go to Step 1 | -- | ||||||||
7 | Using the scan tool, test for current and history Passlock DTC(s). Does the scan tool display "No Communication with Vehicle..."? | -- | Go to Step 6 | Go to Step 8 | ||||||||
8 | Is there any current Passlock DTC or a history B2958 DTC present? | -- | ||||||||||
9 | Attempt to start the vehicle. Does the engine crank fast enough to start the vehicle? | -- | Go to Step 10 | Go to Step 13 | ||||||||
10 | Using the scan tool, monitor the "passlock code" from the Passlock Data List. Does the scan tool read "Passlock Code Open"? | -- | Go to Step 11 | |||||||||
11 | Does the engine start and run? | -- | System OK | Go to Step 12 | ||||||||
12 |
Is the repair complete? | -- | Go to Step 1 | -- | ||||||||
13 | Refer to Starting System Check in Engine Electrical. Is the repair complete? | -- | Go to Step 1 | -- |
Diagnostic System Check - Theft Deterrent Export
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
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The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Inoperative in Data Link Communications |
Does the scan tool communicate with the Immobilizer Module? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Components in Data Link Communications | |
3 | Select the Immobilizer Module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 4 | Go to Powertrain On Board Diagnostic (OBD) System Check 4.3L, Powertrain On Board Diagnostic (OBD) System Check 5.0 L, Powertrain On Board Diagnostic (OBD) System Check 6.5L, Powertrain On Board Diagnostic (OBD) System Check 7.4L |
Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications |
