Crankshaft Sensor

[HarrytB]

Hi

I've got a Chrysler Voyager 2.4 which has recently had the engine light come on.  Its difficult to start and misfires above 2200 rpm.

 

Plugged an ODB reader into it and it picks up P0335 - which relates to the Crankshaft sensor circuit A.

 

So, replaced the sensor (twice)

Using a multimeter:

• tested power cable (ignition on) - producing 5 volts from PCM
• tested signal cable - producing 5 volts, so magnet is engaged in sensor.
• tested continuity of ground - all good.
• tested continuity of live, signal and ground back to the PCM - all good, no cross circuit to ground on any wires.
• Camshaft sensor and Crankshaft sensor share common live - continuity is all good there.

If i rotate the Crankshaft using a socket drive slowly and monitor the signal cable from the sensor I'm not seeing a drop in voltage at all - so is my Crankshaft ring knackered - or am i simply turning it to fast ?

 

Any ideas gratefully received.

Thanks

 

 

[gordy]

Hi there, take it engine shut down here for testing. 5v coming into feed the sensor via power cable that's right in all scenarios. Its this 5v output from sensor at signal side that's questionable. 1 to 2 volts yes. What's the signal voltage when engine running though ?

[HarrytB]

I'll get the meter On it tomorrow when I get back from work. Voltage between signal and ground.

If I remove the sensor and turn the crank with a socket+handle, should I be able to feel any "gear teeth" using a small screwdriver? Can't see in there unfortunately.

[gordy]

Hear your going backwards instead of forwards now. What does crank sensor run off, where does it get its signal. Notch on flywheel, several notches, touth missing on starter ring gear (silly yes). Sticking things in sensor hole, what if, gets broken off. Think you just accept it works (or doesn't) by putting sensor in position. Need to look this up. Is it square wave frequency ?

[gordy]

Well all your problems relates to Crank sensor as you predicted. Codes P0355 to P0359 relate. Difficult to start because ECU not getting proper signal from sensor. Misfires/rough running/not going over 2200rpm due to spark timing not being controlled by ECU via sensor signal yet again.

But you have changed it twice, need check wiring or proper Chrysler part. I'm thinking secondhand one to see what happens.

[gordy]

Hi all not too happy about my answer and knowledge on how a crank angle sensor works. Well till now I have just excepted it works if engines running ok. It doesn't work if faults relate to Crank Sensor. Or could it be something else.

So what have we got from Harry, well a hellafa lot to bin the sensor. Difficulty starting, Missfiring and help ma bob P0355 sensor.

Replaced twice, still same so your jaw hits the deck and car shunted to back of garage. Forget it.

Nope Harry plods on with some tests but its a waste of time as you need an Ocilliscope, this is reason I'm back with this thread.

He was right input is 5v and output is 5v but its a square wave formation output with its switching frequency dependent on the crankshaft speed..I'll try get picture on here from pico tomorrow.

Oh Harry you got anything to tell us about your car.

[gordy]

Oh thought you guys would have filled this thread. Got we bit busy at end here. Three pictures to show what happens with Crank Censor. Hope this comes out ok..

[QinteQ]

Gordy, always found the allpar site good for my clue-stick-slap, but not CRD or even Chrysler but all brands are the same parent.

 

One - https://www.allpar.com/forums/threads/removing-the-crankshaft-position-sensor.143426/

Two - https://www.allpar.com/index.php

 

Best of luck lad.