My 96 Dodge Grand Caravan's check engine light is on again. I checked the code. It is 54 - No cam signal at PCM. I noticed that when this happened, the tachometer read zero. Does anybody know it is really the camshaft sensor problem? odometer

 

1st of does the engine start and run? There could be many reason why the tach reads zero. You need to ck with a dvom if you have a 8 volt at cav #3 and ground #2 and cam signal # 1. You could have an open wire or short, or even a bad pcm. To diag this problem you will need a DRB3 scan tool.

 

It happens intermittently and more often now. When the tachometer shows zero, the engine stalls or sometimes the tachometer recovers with a jolt of the car. After the stall, the engine can be restarted. I took out the camshaft position sensor. It looked fine. I cleaned it and put it back. I feel the engine is stronger, but the stall still happens. I hope it's not the PCM problem. Any suggestion will be greatly appreciated.

 

I have compared the old cam sensor with a new one using a scope and found the rising edge is different. The old sensor's rising edge (output signal from 0v to high) is much longer than the new one.Forgot how much exactly. I changed the sensor and the van looks fine now.