Diagnostic Procedure
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Did you perform the diagnostic system check? If so, go to next step. If not, see DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM.
- Install the scan tool. Turn ignition on, engine off. Record the DTC failure records. Check the transmission fluid level. See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Is the transmission fluid level correct? If so, go to next step. If not, go to step 4.
- This DTC can be set after performing fluid service and filter change, after replacement of the pressure switch manifold, or after a long period of storage. Have any of these conditions occurred? If so, go to step 7. If not, go to step 5.
- Add fluid to the proper level. Is the fluid at the appropriate level? If so, go to next step.
- Check the transmission line pressure. See HYDRAULIC PRESSURE TESTS under PERFORMANCE TESTS. Is the line pressure correct? If so, go to step 7. If not, go to next step.
- No main line pressure at idle may be an indication of the following:
- Stuck or sticking lube regulator valve.
- Stuck or sticking line pressure regulator valve.
- Loose or damaged suction filter.
- Defective suction filter seal.
Was the reason for no line pressure condition found and repaired? If so, go to next step. If not, see SYMPTOM DIAGNOSIS under TROUBLE SHOOTING.
- Perform the following procedure to verify the repair:
- Clear the DTC.
- Operate the vehicle under normal driving conditions.
Did the DTC return? If so, go to step 1. If not, system is okay.