GT-ER

I rebuilt my friends C55 and while the car runs pretty decently it has trouble starting. Upon scanning the vehicles it keeps giving me a P0341 which is the cam sensor. I check the live data and the sensor reads nothing. Put another sensor on and the same thing happens.

Are the cam sprockets identical? I see they have both L and R marks on both sprockets so I assumed they were and installed them randomly. Car runs pretty good so timing should be fine but it makes me wonder if one sprocket has a magnet and the other one doesn't and I installed them backwards.

Only other thing I can think of is that the wiring harness got screwed up somehow but I was very careful with it and nothing was pinched so I don't know.

GT-ER

Or does the sensor have the magnet and the sprocket only has notches?

Anyone have a wiring diagram for this?

BBBSS

Every factory setup I've seen was a magnet in the sensor only. Only place I've seen a magnetic spinning was on aftermarket ignition systems. Did the gap somehow change between the sensor and teeth?

blackbenzz

Sensor has the magnet. Make sure it's seated properly and the wiring isn't cut anywhere

GT-ER

Gotcha...I'll check the harness then. Anyone have a diagram?

betrezra

Could be crank pos sensor too...... That is on its way out.

GT-ER

It's brand new and the car keeps giving me the cam sensor code. I checked the wiring physically and everything looks good. I can't see why it won't work.

GT-ER

Today I checked each wire leading from the sensor to the ECU and they all have continuity. What else should I look for? The car keeps getting the cam sensor short code.

E55Greasemonkey

Both sprockets are the same. You mentioned continuity...but did you check the wires at the cam sensor for short to ground and/or short to each other?

overZealous1

one tooth off after tension?

GT-ER

It's not the timing nor the sprockets, the sensor is definitely not working.

I didn't. I did open up the entire harness to follow the wires all the way to the ecu and found no issues. Some wires do connect to others though and now that you mention this it could be another wire grounding and feeding into the cam wires...aarrggghhh...I hate wiring looms.

Exotic-metal55

Same here on wiring issues. I just went through a month of them myself.

Sprockets are the same and can be used on either side. Did the code just come up or did you pull the heads off and then the problem started when you put it all back together? Any chance the plug is dirt in it? That area gets a lot of belt grime on it and it also can be tricky to seat the sensor all the way in, if dirt is present. Just throwing a few ideas out. Check the fuse?

E55Greasemonkey

Checked the wiring diagram,have a few ideas to check but can't type it all on my phone...Will post later tonight. Suggest running your own ground to sensor and check for 5v input at sensor, youll need to backprobe.

E55Greasemonkey

Pin 1 brn/grn is ground splice shared w/ oil level, intake? Press sens, coolant temp se.s
Pin 2 pink ...direct to ecu
Pin 3 red/blu splice should be 12v..shared w/5-8 injectors

Check pins on connector closely
Try running own ground
Check for 12+ volts.
You could have voltage drop will not always show bad wire when checking ohms.
Any oil in harness?

GT-ER

Great info, I'll check one more time before they take the car today. The plug is clean, no oil or anything. I checked to see if any wires were grounded and only the brn/grn is grounded with little resistance which seems fine. I did not know which wire saw 5v so I didn't check. I'll do that later.

Ever since I supercharged the car it has been having cold start issues but then it runs fine. I always thought it was the injectors since they can't be exactly tuned so easily in the C55 since Jerry has never done one apparently but now I think the issue is just the CPS. I don't know how I could have screwed it up though as I didn't mess with the wiring.

I'm kinda scared the ECU may be fried...what would it take to replace the ECU?

Thanks for all the help guys.

GT-ER

The car has had the CEL forever so I may have not noticed but I think it's been like this ever since I installed the supercharger or ever since I rebuilt the engine...either one. Before that I'm sure it worked fine. I've checked all fuses and they are all fine.

E55Greasemonkey

Check the signal out from sensor -pink wire- engine @ idle, 1.2 to 1.7v ....value alternates. Or use scope. Connect +from meter to pink (backprobe) and - from meter to ground

GT-ER

I don't have a scope, just a multimeter. I hate wiring...lol.

E55Greasemonkey

Do this test 1st

E55Greasemonkey

Dont need a scope, do the test with voltmeter..sry typing on phone

GT-ER

Alright, I'll try it.

GT-ER

Alright, both the red and pink wires have 13v. What could be wrong?

GT-ER

That was the sensor plugged in. Unplugged I get 13v in the red wire and 5v in the pink wire.

BBBSS

You sure you didn't mix those up? If you reverse what you found on those two wires readings then one would be correct and your pink wire to the ECU would be getting 12v from somewhere. Figuring out from where is the fun part.

E55Greasemonkey

OK I have a real keyboard now. I edited my posts. According to the wiring diagram (not always right BTW) You should have battery voltage (12+v) at the red wire, which is a wire also shared with injectors 5-8.

So unplugged, it appears OK, you have the 12v source on the red wire,the 5v in the pink is likely feedback voltage from the ECU, and hopefully you checked resistence through the ground wire.

The concern is the 13v (battery voltage) at the pink wire plugged in, which, according to MB should be 1.2 to 1.7v, of course this info is not always correct. But, what you are looking at is the pulse signal coming out of the sensor. Without a scope to see the pattern, your meter (should be) displaying the voltage of the high and low peaks. Since you are showing 13v at both wires, this would indicate the sensor is shorted internally...which is what the code says right? You said you changed the sensor, was it a brand new one? And just to be sure, did you do this test with the engine at idle, meaning the one test backprobing the pink wire, and the - of the meter to ground?

Another option is to do the same test on your E55 to compare readings. I would think the sensor wires are the same. Just remember you may set a CEL on your E55 with the sensor unplugged and key "ON"