I have a 2004 mini s, it seems there is always something. Power steering, alternator, a/c, and two codes keep popping up po340 and po341, I have changed both camshaft sensor and crank sensor, checked wiring and still have codes come right back.
I have also noticed when shifting from 4th to 5th and from 5th to 6th there is no change in RPM when code is present. Is this possibly a timing issue? Runs great first 20 miles after code is cleared. What am I missing?

 

The P0340 code points to a *wiring* problem (although it can be the ECU) not a sensor problem.

Link:

https://www.kbb.com/obd-ii/p0340/


This link provides some info regarding the P0341 code:

https://www.carparts.com/blog/p0341-...single-sensor/

 

Yes. Yes, there is with these cars. Congratulations / condolences on your purchase and welcome to the forum. You've come to the right place.

So just to be clear for others weighing in: is this car an automatic?

In case this helps, from the Bentley "2002-2006 MINI Diagnosis Without Guesswork" book

 

6 speed manual

 

I am having the same issue, with the same 2 codes. Went through a search on the forum and this is the newest thread, so I figured I would jump on this one as opposed to creating a new one. First, did you end up resolving the issue and what was the root cause?

Bit of backstory on mine (2002 MCS), car was purchased with a seized engine, new block and head, no issues with CEL except for P1477 for about 25-30K. One day while pulling a hill on the freeway, got a flashing CEL. Limped back home and found the tip of the #4 plug to be gone. Borescope showed it (luckily) went through the exhaust. 1 valve damaged, replaced both on that cylinder and went back together. Car was fine driving approximately 400 miles before I began getting the dreaded traction control lamp, which led to a P0340 at first with no CEL and now it transitions between P0340 and P0341. It is also worth mentioning that this would never turn on the CEL at first. Just the traction lamp and it would clear with a key cycle.

Wiring checked ok at the sensor, so I replaced the sensor with a "Dorman" one. Issues seemed to get worse, now I would get the traction light at startup, with the CEL following after the first drive cycle. After much research, went with a Febi sensor without any change in symptoms. Given what had happened before, I considered that the chain may have gotten stretched, even though these are both circuit codes. Didn't want to chance it, the front cover was leaking a bit anyways, and I already had a new chain. Again, no change in the symptoms, and you can feel the ECM change fueling strategies when the code sets, which does take power away and likely resulted in the RPM symptoms mentioned above.

Thank you @Daftlad for posting the above information!! This will be really helpful when I do a deeper dive into the wiring. The wiring part is fairly simple when you have the expected values and pins to rule out with a 3 wire sensor, basically you have:

• B+ to the sensor (Pin 1)
• ECM supplied ground (Pin 3)
• Feedback from the sensor to the ECM (Pin 2)

Since the values at the sensor seemed ok, I suspect that this is a bit intermittent and the issue occurs with a certain amount of load. My plan of attack will be to perform overlays to completely rule out the wiring. I will start by supplying a constant ground to pin 3 and if the code still sets, I will supply battery voltage to pin 1. This will be done at or near the sensor and if I have the correct pins, I will just de-pin the harness and add these as jumpers directly into the connector. If neither of these make a difference, I will overlay the signal wire (pin 2) from the sensor to the ECM.

As a last resort, I will replace the ECM. Luckily, there is a guy nearby that parts these out and has ECMs with keys, immobilizer units, ignition, switched, and key cylinders. I will use this thread to report back any new information, including the eventual resolution.

 

Back with the resolution! It was a circuit problem, just not the one I expected. I picked up a pigtail connector on the way home from a local parts store, since this is a Chrysler connector, they are readily available. The number is S-738 and this is the same one used on the coil. I started by de-pinning the new connector and attaching a length of wire with a ring terminal, which I was going to use for pins 1 and 3. After inserting the new pin, I noticed that the remaining 2 had much larger gaps in them. I tried capturing this in the image below. I started with the signal return, which is on the far right in the image and you can see the silver of the pin is much closer together than on the other 2.

This indicated that the pins would not have as much tension as they should, but this was not the main issue. Closer inspection of the pin I removed showed that the part creating the tension on pin 3 had actually broken and was laying loose inside the pin. So, the root cause in my case was an internally broken pin on the sensor ground (pin 3) and the resolution was replacing all 3 with the ones from the pigtail I got. I didn't change the connector shell because I plan on using it on my coil since the lock is broken on it.

This can happen at the other end (ECM) as well and the reason standard testing didn't catch it was the test equipment was a bit larger that the pin and I didn't insert it because I just held it on the edge. I also missed it on the visual inspection because all 3 looked the same. Lastly, this is not a real common issue to have an internally broken pin. In my 15 years working on vehicles, I only saw this once. Usually, poor pin fit is induced by inserting a probe that is too large. I would chalk my issue up to mileage though since this vehicle does have almost 260k, plus this connector has likely been disconnected a million times.