1999 GMC Sonoma Problems
RepairPal has identified the most common problems with the 1999 GMC Sonoma as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.Refine by vehicle
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.
A Loose or worn gas cap may cause Check Engine Light to illuminate.
The serpentine belt tensioner can fail; it may become noisy and/or the belt may jump off. Replacement of the failed tensioner will be necessary.
The distributor may develop internal faults. This can cause a rough running engine or stalling condition and the Check Engine Light may or may not illuminate. The distributor should be overhauled or replaced to correct this concern.
The heater core under the right side of the dashboard may leak engine coolant which can puddle on the passenger front floor. The loss of coolant may cause an engine overheating condition. Our technicians tell us that removal of the dash board is necessary to replace the heater on these vehicles.
A fluid leak may develop from the transmission output shaft seal. This leak may cause the transmission mount to become oil soaked and require replacement of the mount along with the leak repair.
On vehicles with intermittent windshield wipers, the wiper motor circuit board may fail and cause the wipers to stop working at times. Replacing the circuit board should resolve the issue. Some vehicles were recalled for this problem and some were not. You will need to check with your local dealer to find out if a specific vehicle was included.
The power door locks may stop working in one or more doors due to a failed actuator. Replacement of the failed actuator should correct this concern.