Running on 4 Cylinders

[highrise]

Hi

Some quick advice on this issue would be great.

I've just had both fuel pumps replaced, the car was running well.

I stopped for fuel and started up.

The car was running on 4 cylinders (or what sounded like). I wouldn't rev past 2k.

I managed to limp it to safety.

I've started up a few times and had the same issue.

I'm getting a P0601 code "Internal Control Module Checksum Error"

It sounds like the passenger side (UK Car) bank is not firing.

I've had a mobile mechanic look at the codes and check a couple of coil packs. Nothing obvious.

Maybe an ECU issue on one bank?

I think the engine has independent ECU's per bank?

Many thanks

[Zyox]

I had a similar issue with the crosstalk between the ECUs about 12-13 years ago but it didn't appear as 4 cylinders/limp mode. Just got a check engine light I scanned the codes and got something that sounded very like that. I dug and found out there was an Audi Service Bulletin out that the ECUs needed to be software updated (flashed) as the cache for the crosstalk wasn't being clearly out sufficiently and was filling up with old data causing it to stop working.

Audi <beep> the bed during the flash, pure amateur hour and did it wrong, rang me and told me I needed 2 new ECUs. Thankfully I had a log of the code scans, told them the car went in with two perfectly good ECUs, and if they bricked them while flashing them it was on them to make good. Low and behold the next day they flashed the proper way, at a slower pace apparently, and the update took and no problems since.

Check that this was carried out on yours maybe?
Unfortunately the fix is a main dealer issue as it needs their computers but it should only be an hour or two of labour. They tried to get 6 hours out of me with all their messing but hadn't a leg to stand on so it didn't happen. Good luck.

[highrise]

Thanks for the reply. I think this might relate to the tune and the ECU. I've sent it to the guys that tuned it, so let us see how it goes. Happy Christmas!!

[highrise]

Update: It looks like one of the ECUs is dead.

I don't think there is any available new anymore!

[highrise]

Update: They managed to recode the ECUs to remove the CheckSum error. Hopefully, that sorts it.