Correction
Have any of the following components had service recently?^ The BCM
^ The ignition lock cylinder case assembly
^ The PCM/VCM
If any of the above components have been replaced, the Vehicle Theft (Passlock(TM)) Reprogramming Seed and key (10 Minute Re-Learn) procedure must be performed before any diagnostic procedures are performed.
To assist in diagnosis, the following steps are provided.
1. Does the engine crank but not start? If not, use the Engine Cranks but Does Not Run diagnostic information in the Engine Controls sub-section of the applicable Service Manual.
2. Observe the Security indicator lamp in the lower right corner of the instrument panel when you turn the key to the RUN position. Does the indicator lamp show any of the following conditions?
^ Lamp is On for 5 seconds, then goes Off. This is normal operation. The engine should start and run.
^ Lamp is On and does not go Off. A problem is detected but the engine starts. This indicates that the fault occurred when the engine was running.
^ Lamp does not come On. This is abnormal operation. Use the Security Indicator Inoperative diagnostic in the Theft Deterrent sub-section of the applicable Service Manual.
^ Lamp flashes On and Off. This indicates a problem has been detected this key cycle by the Vehicle Theft (Passlock(TM)) system and the engine may not start.
Important:
You must diagnose the diagnostic trouble codes (DTCs) in the order specified in the DTC table shown. Failure to do so may result in one or more of the following conditions:
^ Extended diagnostic time
^ Incorrect diagnosis
^ Incorrect parts replacement
If none of the above items are true, proceed with the following steps:
1. Install seat covers.
2. Connect the scan tool to the diagnostic link connector (DLC).
3. Enter scan tool diagnostics.
4. Select the model year of the vehicle.
5. Select light truck.
6. Select F1, (Body)
7. Select "M" or "L" for Series.
8. Select F0, Body Control Module.
9. Select F0, (Diagnostic Trouble Codes (DTC)).
10. Select F0, (DTC information).
11. Select F0, (Current DTC).
12. Record on the repair order any current DTCs displayed. If none, skip the next step.
13. Is a current B2960 DTC displayed? If no, the condition is not present with this key cycle. Continue to the next step.
14. Select Exit.
15. Select F1, (History DTC).
16. Are any history DTCs other than B2960 present? If so, diagnose those DTCs first using the appropriate service information, otherwise continue.
17. Select Exit.
18. Select Exit.
19. Select Exit.
20. Select F1, Data Display.
21. Select F6, Security.
22. Cycle the key to the OFF position and wait 20 seconds.
23. Slowly turn the key to the RUN position. Be careful not to turn the key into the START position.
24. Observe the following values:
^ Passlock(TM) Data Voltage should be 5.0 volts.
^ Passlock(TM) State should be Normal.
^ Passlock(TM) Code should be Open.
25. Rotate the key to the START position, and observe the following again:
^ Passlock(TM) Data Voltage should be less than 5.0 volts. Passlock(TM) Data Voltage should remain steady and not fluctuate. The test vehicle used for this diagnostic procedure had a voltage value of 0.92 volts. The vehicle being worked on may be either higher or lower than this value. The key is that it has to be less than 5.0 volts.
^ Passlock(TM) State should be "Monitor Passlock(TM)".
^ Passlock(TM) Code should be Valid Code.
26. If no trouble is found and the customer has experienced one of the symptoms or the code is a history DTC, the most likely cause is the Theft Deterrent (Passlock(TM) wiring, specifically the wires from the Theft Deterrent (Passlock(TM) sensor to the BCM.
Caution:
This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions:
26.1. Air bag deployment
26.2. Personal injury
26.3. Unnecessary SIR system repairs
27. In order to avoid the above conditions, observe the following guidelines:
28. Open the hood.
29. Disconnect the negative battery cable.
30. Install fender covers.
31. Install seat covers.
32. Remove the left sound insulator, if equipped.
33. Remove the knee bolster trim panel.
33.1. Disconnect the park brake release lever cable from the park brake assembly.
33.2. Remove the screws that retain the bolster to the instrument panel.
33.3. Pull back on the bolster in order to release the two retainers. Remove the bolster.
34. Loosen the screw holding C201 together at the connector and separate. C201 is the connector for the steering column wires to the IP wiring harness on the left side of the column about half way down. It is a 48-way connector with a center retaining screw.
35. Separate the turn signal and multifunction switch harness (2) from the 18-way connector (1). They have a locking tab in the center of each connector that needs to be released.
Important:
Use either the correct mating terminal, or electrical tool GM # 12094430, (J 38125-11A) from the J 38125-B Terminal Repair kit. Perform a pull test to determine if the terminals have proper tension. If one is found where the tension is suspect, replace the terminal.
36. Circuit number 1057, Orange with Black stripe wire, in cavity C4.
Circuit number 812, Red with White stripe wire, in cavity B1.
Circuit number 1836, Yellow wire, in cavity D3.
37. On the end of the 18-way connector is the date the ignition switch wiring harness was manufactured. This date is etched in the plastic of the connector. It is displayed as two lines of numbers (ie: GM XXX, XXXX). The bottom row of 4 digits are the 4 digits which must be verified. The following defines the 4 digits:
^ Month (1) Alpha Character (J = January, A = April, 0 = October, N = November, etc.)
^ Day (2) numbers (1-31)
^ Year (1) Number (9 = 1999, 0 = 2000)
38. If the date code is less than N080, (November 08, 2000), solder the terminals to the wires in the following connector cavities of the ignition switch 18-way connector.
^ Circuit number 1057, Orange with Black stripe wire, in cavity C4
^ Circuit number 812, Red with White stripe wire, in cavity B1
^ Circuit number 1836, Yellow wire, in cavity D3
Important:
Connector bolt torque is critical. Tightening the bolt to 7 N.m (61 lb in) may cause the pal nut of the connector to strip. Tightening the bolt less than 4 N.m (35 lb in) may result in an intermittent connection.
39. Connect the turn signal and multifunction switch harness (2) to the 18-way connector (1). Position C210, together tighten the screw holding the wiring harness connectors together.
Tighten
Tighten the retaining screw to 6 N.m (53 lb in).
40. Cycle the steering column tilt from full up to full down a minimum of ten times.
41. Squeeze the ends of connector C201 together with your fingers, forcing the terminals and connector to properly seat together.
42. Recheck the retaining screw for connector C201 torque.
Tighten
Tighten the retaining screw to 6 N.m (53 lb in).
43. Again, cycle the steering column tilt from full up to full down a minimum of ten times.
44. Again, squeeze the ends of connector C201 together with your fingers, forcing the terminals and connector to properly seat together.
45. Recheck the retaining screw for connector C201 torque.
Tighten
Tighten the retaining screw to 6 N.m (53 lb in).
46. Again, cycle the steering column tilt from full up to full down a minimum of ten times.
47. Again, squeeze the ends of connector C201 together with your fingers, forcing the terminals and connector to properly seat together.
48. Recheck the retaining screw for connector C201 torque.
Tighten
Tighten the retaining screw to 6 N.m (53 lb in).
49. Install the knee bolster trim panel to the IP.
^ Connect the brake release cable to the park brake assembly.
^ Install the screws that retain the knee bolster trim panel to the instrument panel.
Tighten
^ Tighten the TORX(R) screws to 9 N.m (80 lb in).
^ Tighten the hex head screws to 1.9 N.m (17 lb in).
50. Install the sound insulator panel, if equipped.
51. Connect the negative battery cable.
52. Observe the Security indicator lamp when the key is turned to the RUN position. The Security lamp should come On for 5 seconds then go Off. If it doesn't, you must recheck your work.
53. Observe the SIR lamp. The lamp should be Off.
54. Remove the fender covers and close the hood.
55. Remove the seat covers.