What to know about the Top Dead Center (TDC) Sensor:
All engine, whether a single cylinder engine or a V8 engine, has top dead center. This position is a reference point for engine timing and indicates when a spark plug should fire, igniting the fuel the cylinder’s combustion chamber. Top dead center is when the piston is at the very top of its compression stroke. At this position, the intake and exhaust valves in the cylinder head are closed and the air-fuel mixture is compressed in the cylinder.
The TDC sensor monitors a reference point on the camshaft that shows where top dead center is on a cylinder, usually cylinder number one. It sends a signal to the engine control module which, in turn, communicates to send a spark to the cylinder at top dead center. The spark ignites the fuel and the power stroke begins as the piston is forced downward. The TDC sensor is an electrical component and is prone to failure due to corrosion, cracking, or wearing out. If that happens, the engine control module may not receive a correctly timed signal and the spark may be sent to the wrong cylinder at the wrong timing, causing your engine to run rough or not run at all.
Facts to Note:
The top dead center (TDC) sensor is integral to the proper timing of your vehicle. If it is fixed incorrectly, your vehicle will not run or run very poorly.
How to Fix:
The vehicle battery is disconnected
The faulty top dead center sensor is removed
The new top dead center sensor is fixed
The battery is connected and the engine is scanned and cleared of codes
The repair is confirmed and the vehicle is road tested for proper operation
If your car’s Check Engine light turns on, or if the engine will not run or runs poorly, have one of your expert mechanics check the problem and change the TDC sensor if needed.
Common symptoms indicating you may need to change the Top Dead Center (TDC) Sensor:
Engine will not fire or run
Engine runs poorly and misfires
Check Engine light is on
Backfiring is heard from the exhaust
Importance of this service:
Since the TDC sensor is integral to a running engine, it is vital to address the operating issues associated with it as soon as you can. Other than a possible stalling condition, there are no associated safety concerns with the TDC.