Diagnostic Starting Point

WARNING: This page is about a different car, the 2002 Infiniti QX4, 2001 Nissan Pathfinder, and 2001 Infiniti QX4. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: In addition to transmission-related DTCs, engine-related DTCs may be output during RETRIEVING DIAGNOSTIC TROUBLE CODES procedure. These DTCs pertain to engine performance and must be repaired first, as engine performance will greatly affect transmission operation. For information and testing procedures of engine-related DTCs and components, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

Ask customer if any symptoms are present (if possible) and record. Determine if vehicle is in fail-safe mode. See FAIL-SAFE under DESCRIPTION & OPERATION. Connect scan tool to DLC. Retrieve and record DTCs and freeze-frame data. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Go to next step.
Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Go to next step.
Inspect transmission fluid level and condition. See appropriate SERVICING article. Perform ROAD TEST under PERFORMANCE TESTS. Record any symptoms that occur during road test. If any DTCs were recorded in step 1, ensure all conditions were met in appropriate DTC CONFIRMATION PROCEDURE during road test. See appropriate DTC under DIAGNOSTIC TESTS. Go to next step.
Perform line pressure test. See HYDRAULIC PRESSURE TESTS under PERFORMANCE TESTS. Record results. Perform STALL SPEED TEST under PERFORMANCE TESTS. Record results. Go to next step.
Retrieve and record DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Perform TCM SELF-DIAGNOSTIC PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Record flash codes. Go to next step.
Diagnose and repair DTCs and flash codes listed. Repair any engine performance related DTCs before any transmission related DTCs. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. Perform appropriate DTC confirmation procedure after each repair is completed. Perform ROAD TEST under PERFORMANCE TESTS to confirm transmission is operating correctly. Go to next step.
If no DTCs or symptoms are present, repair is complete. If problem is still present, diagnose concern by symptom. See SYMPTOM DIAGNOSIS . If a particular component is suspect, diagnosis and repair as needed. See COMPONENT TESTS . Go to next step.
After repairs are completed, clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Perform ROAD TEST under PERFORMANCE TESTS to confirm transmission is operating correctly. If no DTCs are present and transmission is operating properly, repair is complete. If transmission is not operating properly, go to step 1.