Section 70 (Automatic Transmission Diagnosis - 4L80-E (Gasoline)): Description: Self-Diagnostics
WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1998 GMC Savana Special, 1998 GMC Savana Camper Special, 1998 GMC Savana, 1998 Chevrolet RV Cutaway, and 1998 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
VCM constantly monitors all electrical circuits. If VCM detects circuit problems or sensors out of range, it will record a Diagnostic Trouble Code (DTC). If problem continues for a predetermined time, Malfunction Indicator Light (MIL) will glow.
If MIL is on all the time, DTC(s) are currently being detected. If MIL is off, but VCM had detected a circuit or sensor problem, DTC(s) will be stored in computer memory.
Stored DTCs may be retrieved from VCM memory using a scan tool. DTCs CANNOT be retrieved by grounding 16-pin Data Link Connector (DLC).
NOTE:
Faulty engine sensors and actuators may cause transmission related DTCs or driveability problems. Engine faults and related DTCs must be diagnosed and repaired before transmission codes are repaired. For additional information on diagnosing and repairing engine-related VCM trouble codes, see SYSTEM/COMPONENT TESTS in ENGINE PERFORMANCE:
- SYSTEM/COMPONENT TESTS - (4.3L 1997).
- SYSTEM/COMPONENT TESTS - (4.3L 1998).
- SYSTEM/COMPONENT TESTS - (5.0L 1997).
- SYSTEM/COMPONENT TESTS - (5.0L 1998).
- SYSTEM/COMPONENT TESTS - (5.7L 1997).
- SYSTEM/COMPONENT TESTS - (5.7L 1998).
- SYSTEM/COMPONENT TESTS - (7.4L 1997).
- SYSTEM/COMPONENT TESTS - (7.4L 1998).