2012 Fiat 500CRM Mitchell1 2022-05-20T22:01:41+00:00
- Engine fault code: P0340-Camsaft sensor signal implausible. Usually this fault means the cam sensor is inop or there is a circuit problem. However on this platform cam timing problems can also cause this code. Code sets right away, and engine runs rough. Connect lab scope to the cam and crank signals at the PCM. Both sensors produce the correct 5V wave forms, so the circuits and sensors are okay. Using a known good wave form from Identifix, was able to determine the cam/crank mechanical relation is off by 5 crank trigger-wheel teeth, which should equal 3-4 cam teeth. Timing belt interval is 152,000 miles. Removed upper timing cover to inspect belt condition (one bolt is missing), found looks normal, and is tight. Timing on this engine has to be done with a special tool set after the timing cover and vacuum pump have been completely removed to allow tools to be installed. There are no timing marks for visual conformation. Based on lab scope findings, the next step is to tear down the engine to install alignment tools to verify, then likely install new timing belt and other drive components. This vehicle is equipped with a RV tow bar and is a manual trans. It is possible to cause timing belt to jump if engine is rotated backwards, since it has a spring loaded tensioner pulley that does not lock down. So if it was left in gear and pulled/backed by a tow vehicle, this could be the cause of belt misalignment. Upon tear down, confirmed timing belt has jumped 3 teeth. Found small piece of plastic inside the cover that has wear from timing belt rubbing on it. Suspect this piece made the belt jump.
- TIMING BELT – Remove & Replace – Normally Aspirated
- (Combination) – CAMSHAFT SEAL – Remove & Replace
- (Combination) – TIMING BELT TENSIONER – Remove & Replace
- (Combination) – WATER PUMP – Remove & Replace Normally Aspirated – [Includes:Drain and refill Low Temperature Cooling System.]
- Hazardous Waste Disposal Fee
Tom A. gave our service a 5 star review on 5/19/2022