2004 Pontiac Bonneville Problems

RepairPal has identified the most common problems with the 2004 Pontiac Bonneville as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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Known Problems

It is common for the fuel level sensor in the fuel tank read the fuel level incorrectly. The sensor must be replaced to correct the condition. Our technicians recommend having the complete fuel pump module replaced on high mileage vehicles.

The crankshaft position sensor may fail causing the engine to stall intermittently, the Check Engine Light may or may not illuminate.

The water pump may develop a coolant leak resulting in an engine overheating condition.


The intake manifold gaskets can develop external engine oil or coolant leaks. The intake manifold will need to be removed and the gaskets replaced to correct this issue. In some cases the plastic intake manifold my be damaged requiring replacement.

An ignition coil may fail causing one of the cylinders to misfire. Each of the two banks of cylinders has its own coil assembly. If one ignition coil fails the coil assembly for the corresponding cylinder bank must be replaced.

The transmission pressure control solenoid may fail causing erratic shifting. Our technicians tell us that partial dis-assembly of the transmission is necessary to replace a failed pressure control solenoid.

The mass air flow or crankshaft position sensor may fail causing the engine to stall intermittently. Proper diagnoses will be necessary to determine the cause of any stalling condition.

One or more heater & AC (HVAC) air delivery and/or temperature mode door actuator may fail. This can result in incorrect air delivery or temperature. If this occurs, fault code(s) stored in the HVAC control module should be available to assist with diagnoses.

Illumination of the Check Engine Light can be caused by a loose or worn gas cap.

You may be able to prevent transmission problems by servicing the transmission and inspecting the fluid every 30,000 miles. If the fluid is dark or burned then the transmission system should be completely flushed.

The spark plugs should be replaced every 100,000 miles. Our technicians recommend replacing the spark plug wires also at this time.

The engine may develop an oil leak from the lower crankcase portion of the engine block. Our technicians tell us that the engine must be removed from the vehicle to properly repair this oil leak.

Our technicians recommend flushing the brake fluid every 60,000 miles.  Brake fluid that is dirty may cause problems in the brake system.

Extended life coolant may become contaminated and require cooling system service before the recommended 100,000 miles.

An intake manifold vacuum leak can develop from a variety of sources, often causing illumination of the Check Engine Light with codes P0171 & P0174 stored. Thorough diagnoses will be necessary to pinpoint the cause in order to make the correct repairs. A "smoke" machine is often used to isolate the cause of difficult to find vacuum leaks.