GMC Repair and Maintenance
A guide to problems, costs, maintenance and repair for your GMC
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GMC ProblemsCheck Engine Light With Code P1870
Vehicles equipped whit a 4 speed automatic transmission may develop a harsh 1-2 shift and/or illumination of the Check Engine Light with code P1870 stored. This can be caused by wear of the bore for the TCC isolator and regulator valves in the valve body. This condition does not commonly occur until the transmission reaches normal operating temperature. If the valve body is worn, replacement will be necessary to correct this concern.
The fuel level sensor in the fuel tank may fail causing erratic fuel gauge operation. Our technicians tell us that on high mileage vehicles you may wish to replace the complete fuel pump module assembly if this condition occurs.
On certain 2005 - 2007 vehicles, General Motors has provided a special service policy covering the fuel level sensor, agreeing to pay 50% of the repair cost. This coverage extends for 10 years or 120,000 miles from the original "in service" date of the vehicle. Please contact your local GM dealer for more information.
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GMC QuestionsReplaced the starter, crank but not start, coils not firing,new sensor bcm/pcm (2 answers)
The coils aren't firing at all, everything else working including fuel pump, replaced crank sensor, and cam sensor too. Lost. No codes coming up, all grounds checked
on star cant diagnose the problem since radio doesn't turn on . already tried shutting car roff locking doors wait 4 min go back in car turn it on still no radio or on star booth green and red on star buttons not working
When shutting off engine, dash gauges go down as I would expect. 5 sec later they go back up. Something is not shutting off.
GMC RecallsSoftware Defect May Prevent Airbags From Deploying
If the airbag system is in a diagnostic test mode during a crash, the deployment of the frontal airbags and seat belt pretensioners will not occur. Dealers will reflash the system software. In the event the vehicle has had a previous airbag deployment, the airbag sensing and diagnostic module (SDM) will be replaced free of charge.
The ignition key may be able to be removed from the ignition switch without having the transmission shift lever securely in the park position. This could allow the vehicle to roll unexpectedly. Dealers will inspect and if necessary replace the key cylinder lock housing free of charge to resolve the concern.
The tire placard may list the improper tire size and inflation pressure. Dealers will inspect and replace affected certification labels free of charge to resolve the concern.