The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual service repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technical expert with the latest OEM information.
Intermittent Vehicle No Crank/Dead Battery
2004 Buick Rainier; 2000-2004 Cadillac Escalade, 2002-2004 Cadillac Escalade EXT, 2003-2004 Cadillac Escalade ESV; 1998-2004 Chevrolet Blazer and S-10 Pickup, 1999-2004 Chevrolet Silverado, 2000-2004 Chevrolet Suburban and Tahoe, 2002-2004 Chevrolet Avalanche, 2002-2004 Chevrolet TrailBlazer and TrailBlazer EXT, 2003-2004 Chevrolet Express; 1998-2004 GMC Jimmy and Sonoma, 1999-2004 GMC Sierra, 2000-2004 GMC Yukon and Yukon XL, 2002-2004 GMC Envoy and Envoy XL, 2003-2004 GMC Savana, 2004 GMC Envoy XUV; 1998-2004 Oldsmobile Bravada; 2003-2004 HUMMER H2
When diagnosing an intermittent vehicle no crank or dead battery condition, remove and reinstall the ignition switch following the appropriate procedure in the Service Information. The ignition switch may have been misindexed in the steering column during a previous replacement.
If the ignition switch is misindexed in one direction, the ignition switch circuits will not be completely open when the ignition switch is in the Off position with the key removed. This may result in the lights remaining on and will drain the battery.
If the ignition switch is misindexed in the opposite direction, the ignition circuits will open correctly, but the ignition switch may not close the crank circuit properly when the ignition key is turned to the crank position. This will result in a no crank condition.
Refer to GM bulletin 04-06-03-002 for more information.
Low Voltage Display
1998-2008 GM Passenger Cars and Light Duty Trucks, including Saturn; 2003-2008 HUMMER H2, H3; 2005-2008 Saab 9-7X
These vehicles may have a low voltage display (Fig. 9), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer-added electrical accessories or with a discharged battery.
Fig. 9
These are normal operating characteristics of a vehicle electrical system unless a proven fault has been diagnosed.
Non-usage of the vehicle for ex tended periods of time and extended periods of engine idling with high electrical loads are two factors that may affect generator and battery performance. For complete diagnosis of the battery and/or generator, refer to the appropriate Service Information.
Refer to GM bulletin 05-06-03-002B for more information.
Starter Motor Continues to Run or Crank
1995 Buick Riveria; 1995 Cadillac Eldorado, Eldorado Touring Coupe, Seville; 1995 Chevrolet Camaro; 1995 Oldsmobile Aurora; 1995 Pontiac Firebird - with 3800, 4.0L, 4.6L, 5.7L engines (RPOs L47, L36, LT1, LD8, L67, L37); 1994-95 Chevrolet and GMC Truck C/K, G, P models - with 5.7L, 7.4L engines (RPOs L05, L19)
The starter motor may continue to run or crank after the vehicle is started or turned off. The starter motor solenoid will not disengage because of a ground to the #6 circuit. With the #6 circuit ground to a resistive ground, current is fed back through the windings to the ground, holding in the plunger and causing the starter to continue to run.
Disconnect the #6 circuit lead at the starter "S" terminal. With the ignition Off or in Run, use an Ohm meter to check for any electrical path between the ring terminal on the #6 circuit lead and ground.
If found, eliminate the grounding condition. Reroute any wires as necessary.
Alternator Bolt Tightening
2001-2004 Honda Civic
Conditions such as an engine crank/no start, MIL on, immobilizer blinking, or no communication with the ECM/PCM may be caused by loose alternator bolts. If these bolts are loose for any reason, the alternator can overcharge and damage the ECM/PCM.
Beginning in 2001, the Civic has a different style alternator bracket that makes the bolt tightening sequence and bolt torque critical. Improper tightening will cause noise.
Refer to the appropriate Service Information for the proper bolt tightening sequence and bolt torque specifications. A belt tension gauge special tool also is required.
After tightening the alternator bolts, restart the engine. If it won't start, check the ECM/PCM connector for battery voltage and ground. If there is battery voltage and ground at the connector, replace the ECM/PCM.
Leave a comment