'01 C4 Cab misfiring after replacing Variocam
06-11-2016, 12:35 AM
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'01 C4 Cab misfiring after replacing Variocam
Hi all, I picked up my new-to-me 2001 C4 Cabriolet with 47,000 on the clock about 2 months ago, and it's spent almost half of that time on a lift being worked on. The first item that I had to replace was the Bank 1 VarioCam Actuator (it was throwing a code). I elected to do it myself to learn more about the car, and I'm pretty glad I did. I found out that the engine is not original to the car when I tried to pull the IMS bearing, and found that it was out of a '06-08, and cannot be removed without splitting the case. At least it's been replaced recently, I guess. So I replaced the actuator, along with the spark plugs and tubes, made sure the timing was exactly where I found it, and put everything back in the car. I turned it over for the first time in almost 2 weeks, and it was a success! The car idled much smoother! Then 2 minutes later, it threw another code saying that the camshaft position sensor for bank 1 was faulty.
Get the sensor replaced, turn the key and... something is very, very wrong. The car idles like it's going to die, fluctuating between 150 and 800 RPM. Eventually it settles down around 800, until I give it some gas, then it dies down and starts fluctuating again. I hooked up my Durametric software to it, and found that it had codes P0343 and P0300. I checked out the misfire count, and they're all on bank 1. I checked the camshaft actual angle and position deviation, and bank 1 shows nil for both values.
This leads me to believe that there is an issue with the wiring somewhere, which would explain the P0343 code and the nil values for the camshaft position sensor.
Could a fault in the wiring cause misfires, or is it a separate issue?
Durametric screenshots:
<blockquote class="imgur-embed-pub" lang="en" data-id="a/PaLom"><a href="//imgur.com/a/PaLom">View post on imgur.com</a></blockquote>
Get the sensor replaced, turn the key and... something is very, very wrong. The car idles like it's going to die, fluctuating between 150 and 800 RPM. Eventually it settles down around 800, until I give it some gas, then it dies down and starts fluctuating again. I hooked up my Durametric software to it, and found that it had codes P0343 and P0300. I checked out the misfire count, and they're all on bank 1. I checked the camshaft actual angle and position deviation, and bank 1 shows nil for both values.
This leads me to believe that there is an issue with the wiring somewhere, which would explain the P0343 code and the nil values for the camshaft position sensor.
Could a fault in the wiring cause misfires, or is it a separate issue?
Durametric screenshots:
<blockquote class="imgur-embed-pub" lang="en" data-id="a/PaLom"><a href="//imgur.com/a/PaLom">View post on imgur.com</a></blockquote>
06-11-2016, 03:35 AM
#2
It's likely both issues are related but regardless since the DME complains about P0343, it needs to be fixed anyway. Per the DME 7.2 diagnostic manual, P0343 means the bank 1 cam signal is ABOVE limit, which means shorted to B+
Unplug the cam sensor and check if pin 2 (red/green wire) has 12v with key ON engine OFF. If it does, you found your problem and you will have to trace upstream all the way to the DME (plug III/pin 20). Also check if you get the 5v on pin 3 (red/violet wire) with key On engine OFF. That pin supplies power to the sensor.
Unplug the cam sensor and check if pin 2 (red/green wire) has 12v with key ON engine OFF. If it does, you found your problem and you will have to trace upstream all the way to the DME (plug III/pin 20). Also check if you get the 5v on pin 3 (red/violet wire) with key On engine OFF. That pin supplies power to the sensor.
