Trouble Code: P0320
No Crank Reference Signal to PCM
Possible Causes:
CKP Sensor signal circuit is open or grounded.
CKP Sensor VREF circuit is open or grounded.
Tone wheel or flex plate damage or erratic CKP Sensor signals.
CKP Sensor is damaged or has failed.
PCM has failed. 4.7L
The Crankshaft Position Sensor (CKP) is mounted into the engine block above the starter motor. Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the powertrain control module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing. The sensor is a Hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
On the 4.7L V8 engine, a tone wheel is bolted to the engine crankshaft. This tone wheel has sets of notches at its outer edge. The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.
4.7L
The Crankshaft Position (CKP) sensor is bolted to the side of the engine cylinder block above the starter motor. It is positioned into a machined hole at the side of the engine block.
The Crankshaft Position (CKP) sensor is bolted to the side of the engine cylinder block above the starter motor. It is positioned into a machined hole at the side of the engine block.
same issue here, mi WJ 03 V8 4.7L started with the check engine light on, when iddle revs when up and down and shut shutt engine off fou a couple of weeks. one morning just wont start changed the Crankshaft Position Sensor located (around 35dlls on Autozone) just above starter + a 30 min job. worked great no problem now.
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Code P0320 no crankshaft reference at PCM.......most likey both problems are related sounds like you need to replace the crankshaft sensor, it is located on the right side of engine block, just above the starter motor, we see a lot of these fail. if you let it go to long you might get to take long walk, i will tell you what my farther used to tell me, if you don't want to fix it then don't drive it no farther then you want to walk.
let me know if there is any thing else i can do for you.
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I don't entirely agree with the diagnosis offered. I feel that a faulty crank sensor would make the engine hard to start or prevent it from starting at all. I actually had a crank sensor problem previously with a Chrysler Cirrus, it just died with no warning. This engine starts fine and runs fine except for the occasional "buck" and the idle speed issue. When I called to price the crank sensor I had a discussion with the parts person at my local Jeep dealer and he didn't really think that my problem was a crank sensor either. I realize that he is obviously not an expert but I am inclined to agree with him. Also the code reader I used to read the code - P0320#10 states: "Ignition/Dist Engine Speed Input Circuit" not the description "no crankshaft reference at PCM" as offered. I appreciate the help of johnjnail but I would like a second opinion. I also would like to add that there 232,000 km on the vehicle which I forgot to add in the initial correspondence.
If I get the second opinion to match the first, I guess I may have to reconsider.
Thx, Jim
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