Camshaft Position Sensor

[ChrisP147]

Just fired up AlfaDiag for the first time to find out why the MCSF warning keeps coming on, and it won't go above 3k RPM - the fault code says that it's a problem with the camshaft position sensor circuit, just wondered what the text "Fault Symptom: Above Maximum Limit" means in the message below? Has it still failed outright? I've found another previous post which says to first test the wiring with a multimeter, and then to just replace the sensor if the wiring's OK.




Failed Component Code: Camshaft Position Sensor Circuit (Timing Sensor)
Fault Symptom: Above Maximum Limit
Warning Lamp Status: Warning Lamp Illuminated
Fault Test State: Test not complete for this Error.
Fault Code Storage State: Error Present at time of request
Event Count: 40 count
Environmental Condition One: Engine Speed: 1640 rpm
Environmental Condition Two: Relative Load: 34.5 %
Environmental Condition Three: Engine Coolant Temp: 18.75 °C
Environmental Condition Four: Air Temp: 24.75 °C
Environmental Condition Five: Throttle Valve Angle: 0 °
Environmental Condition Six: Battery Voltage: 11.7126 volts

[ChrisP147]

Does anybody have any ideas on this please? Cheers

[GialloEvo94]

The status code of "Above Maximum Limit" for fault code P0340 (Engine Timing Sensor) means the sensor has a short circuit with battery +ve, or it is open circuit.

[ChrisP147]

That's interesting, hopefully it won't need to be replaced then... do you know whereabouts this might be occurring? The connector on top of the engine is intact and tightly connected, could it be chafing of the wires at the sensor itself that are touching the engine casing? Just changed the timing belt and wondering if there were any wires which I didn't pin up correctly...

[armoore]

How did you lock the exhaust camshaft? Also it is possible that damage was caused when tightening the cam wheel nut.

[ChrisP147]

I put an extension bar through one of the sprocket holes, which did result in bending the metal ring which passes through the sensor. Like an idiot I tapped it back into shape (what I thought was a true circle!) and hoped it wouldn't cause any problems. Could this have broken the sensor, or could it just be mis-reading because of the metal circle being slightly out of kilter?

[symon]

Originally Posted by ChrisP147

I put an extension bar through one of the sprocket holes, which did result in bending the metal ring which passes through the sensor. Like an idiot I tapped it back into shape (what I thought was a true circle!) and hoped it wouldn't cause any problems. Could this have broken the sensor, or could it just be mis-reading because of the metal circle being slightly out of kilter?

That will have almost certainly have broken the sensor IMO.

[ChrisP147]

Oh dear, looks like I'll be taking a trip to the dealers soon then! Does anybody know what the part number is for the cam sensor, I can't find it on ePer? Cheers.

[symon]

I take it your 147 is a petrol?

Either way it is listed here

Fiat Parts and Alfa Romeo Parts from Shop4Parts

No need to go near a dealer for this one..

[iainfm]

Factors have sensors. I paid £60ish quid for mine. Dealer wanted nearly £120!

[j999evo]

Just got exactly the same symptoms on the 156 2.0TS - orange engine light on, car won't run above 3k revs but is sweet up to that point although a bit hard to start, diagnostics at my friendly non-Alfa garage says "phase sensor".... sounds like we know what it is - can anyone else confirm this is a fail mode for the cam sensor on the TS engine? I've had one go on both my integrales (old 8V and 16V engine) and the car wouldn't start, on a Fiat Coupe 16VT (car started, did strange things around 4k revs then ran fine) and on my current Coupe 20VT (wouldn't start). The failure symptom seems to change with the appplication - just curious.

Ah well, at least the variator needs doing, so it's kinda worthwhile pulling the cambelt off 8k miles after it was changed.... all part of life's rich pattern...

DBP

[Smaky]

Interesting one this, the damage to the Cam ring will be causing errors, but the sensor wont be damaged, just picking up the wrong signal and between that, the crank sensor and the ping sensor the engine will fire out of turn, the ring is what needs to be replaced, and I'm guessing you had the car wasn't running when you pulled the codes hence the <12V warning, You can also get that warning if the Variator solenoid (71736025) is faulty and isn't phasing the inlet cam correctly.

But

[ChrisP147]

Thanks for the headsup about the Shop4Parts cam sensor, and Smaky that's nice to know that the sensor might not be damaged! The cam ring on the sprocket could only have been millimetres out of line, as I bent it back into as circular a shape as possible. It is strange though, because the problem didn't occur until about 10 miles after startup from changing the timing belt, then it lasted for 10 minutes, and the problem went away soon after. Then about 90 mins later the problem reoccurred and has been on ever since. Could possibly be the variator solenoid as I had that out to fix a leak when I did the timing belt... I tested the solenoid when it was out and it clicked into action when hooked up to DC..... is there any other way to test this, perhaps using the Test sequence in AlfaDiag??

J999evo that's exactly the same as what's happening with mine, you know if you accelerate quickly to 3k revs and then change gear it can actually still feel like you've got a fully functioning engine!

[j999evo]

Thanks guys - ChrisP147, I hope you sort yours out soon. My local guy "couldn't clear the fault" which does indicate that on mine, it's a hard fault on the cam sensor, rather than a slightly damaged cam ring - I'll let my specialist chap take over from here - having spent last weekend chinging the fron wishbones, my knuckles are just recovering!

Well, the shopping list is growing... We've got to do a cam sensor, variator, get an MOT, pay the road tax and fix the aircon before we go off round Europe on hols in August - I can feel a Brera coming on... (in my dreams!)

DBP

[ChrisP147]

Thanks j999evo, managed to get the sensor out yesterday and found .5mm wear on the sensor from where the metal sprocket had been rubbing on it - looks like it's a new sensor for me! I know what you mean about the ever-growing shopping list!

Just found the sensor for £40 from "Online Automotive" - does anybody have any experience of these? It says the sensor is for the 1.6i , didn't know there was a difference between a 147 1.6 and 1.6i , they're both injected aren't they?! Please could someone just have a quick look and make sure this is the right sensor for my 1.6 2002 147?

Cheers

[GialloEvo94]

Originally Posted by ChrisP147

Just found the sensor for £40 from "Online Automotive" - does anybody have any experience of these? It says the sensor is for the 1.6i , didn't know there was a difference between a 147 1.6 and 1.6i , they're both injected aren't they?! Please could someone just have a quick look and make sure this is the right sensor for my 1.6 2002 147?

All the Twin Spark engines are injected and all the TS engines used in the 147 (1.6 or 2.0) use the same Camshaft Position Sensor. This is Alfa Part number 46469912 which corresponds to part reference CS1122-OL on the Online Automotive website. Alfa dealers charge over £120 for a new Camshaft Position Sensor sensor so it's a very good price.

[chebik]

ChrisP147, did u fix the problem and how?

[ChrisP147]

Hi Chebik,

Yes I managed to sort the problem by replacing the camshaft sensor. The local motorspares shop had it for £56. It was a bit of a pig to get the connecting wires out of their holders, but still doable. It turned out that I had dinked the exhaust sprocket so that the thin bit of metal that passes through the sensor was not completely true, and so it had rubbed away at the top layer of plastic on the sensor.

If you go through the process of changing the cambelt then once you've got the exhaust sprocket off you can change the sensor.

[CroBaron]

I dread the day mine goes as it's a pig of a job to do.