2012 Passat B7 1.6 TDI Electrical issues

[Twolitrepinto]

Hi everyone,

I'm new here so hello and all that!

Anyway, the car is a 2012 Passat B7 1.6 TDI (CAYC)

A friend asked me to have a look at this car after it broke down.
we found that the ECU was heavily corroded, and that this is a common problem, so he sent it off for repair.
They couldn't repair it, so instead he had it cloned.

After plugging the cloned ECU back in, it now runs and drives but does not boost and has several other strange faults.
(Scanned with Autocom)

P2426 Exhaust Gas Recirculation Cooling Valve Control Circuit Low
P0047 Turbocharger/Supercharger Boost Control "A" Circuit Low
P261A Coolant Pump "B" Control Circuit Open.
P2112 Throttle Actuator "A" Control System - Stuck Closed
P261B Coolant Pump "B" Control Circuit Range/Performance

It also has faults in the ESP and Parking brake module stating "No Communication with Engine Control Module", can't remember the codes for now.
Also TPMS has stopped working altogether.

Glow plug light is flashing permanently.

I'm a mobile mechanic but I've been out of the game for a while and tbh I'm out of my depth with a lot of these types of electrical issues.

I am not an auto electrician but I have inspected the ECU connectors visually, and all the pins look OK with no sign of water ingress or corrosion.
I've also checked all engine bay fuses and wiring just visually by removing the fuse box and inspecting all connections but can't find anything obvious.

Battery is OK, Alternator is charging (although voltage is a little high IMO? it reaches 14.9V)

I suspect that this cloned ECU is not fully playing ball for whatever reason, or there is a wiring fault hidden somewhere, but I am at a loss with how to find this out.

I do have access to VCDS, but have limited knowledge on how to use it!

I've now bought the car for a decent price for myself to try and fix, as the previous owner has had enough of it, and it is in very good condition and well looked after for it's age & mileage.
I want to keep it and scrap the POS Renault Megane that is currently falling apart from underneath me .

Any help would be greatly appreciated and if anyone can point me in the right direction, I will buy them a few beers for sure!

Thanks in advance!

[Crasher]

I would say the used ECU has a similar water damage problem. I went through three used ECU's on one car recently until I found one that MAY not have the same fault as the other two and the original but even after having ACTronics check and reflow the board I am not convinced as I still have one of the original faults, the wring is perfect plus the component is new and genuine.

[Twolitrepinto]

Hi Crasher,

I was hoping you would reply, as you seem to be knowledgeable on this subject from some of the other posts i've read!

The replacement ECU came at a cost of £450.
It looked like a new Continental unit, but on closer inspection, it has just been painted with a new sticker slapped on it.

The company who did it admitted that this can sometimes happen so we have sent this "refurbished" ECU back today for a partial refund and they are going to return the original ECU.
I am hoping that I will then be able to then read it myself via VCDS or whatever software is required so that I can replace it myself and hope this solves the issue.

[Twolitrepinto]

Just a couple of questions...

Can I use an ECU from say, a Golf 1.6 tdi with the CAYC engine?, or does it have to be from a Passat?
Does the part number and software version all have to match exactly?

Also can I read / write all required data to the ECU's using only VCDS or is there more involved than that?

Thanks again for your help.

[Crasher]

VCDS can't do any of this. You would need the dealer system ODIS with GEKO security clearance and getting this is nearly as difficult as getting an appointment with your GP. Just plugging in and coding an ECU using ODIS means you must have the exact corcet part number with suitable software level and with highly specialised extremely expensive aftermarket equipment ECU's of the same type can have suitable software installed.

[Twolitrepinto]

VCDS can't do any of this. You would need the dealer system ODIS with GEKO security clearance and getting this is nearly as difficult as getting an appointment with your GP. Just plugging in and coding an ECU using ODIS means you must have the exact corcet part number with suitable software level and with highly specialised extremely expensive aftermarket equipment ECU's of the same type can have suitable software installed.

Thanks for the info!

Is this something you would be able help me with at all?

If I can find a matching ECU with the correct software version, I could bring the car to you as I don't think I'm to far from you?

Thanks again

[Crasher]

If you find a used ECU with the exact matching part number (what is the VIN and the numbers off the other ECU’s) I can usually rematch a used ECU with ODIS. If not I know a man who can but he is in Derby and may not travel as far as Lincoln. He is coming to do an ECU mod on an A4 for me next week so I will ask him. At the moment I don’t have ODIS as the Wi-Fi board on my Dell laptop did something to its driver and Dell drivers are apparently unique so I am waiting for its return.

[Twolitrepinto]

Hi Crasher.
Sorry it's been a while, I put this on hold temporarily due to limited finances.

I have been looking around for a used replacement with the same part numbers and have a couple of questions.

My ECU has 2 part numbers, which are identical.
I have found similar ECU's which have a different part number, but the 2nd part number (smaller writing) is the same. Same HW version but its from a caddy and looks to not have corrosion.

Would this be a possible candidate or do ALL part numbers have to match?

Original ecu
IMG_20240614_155231_915.jpg

Potential replacement?
IMG_20240617_122641.jpg

Never mind, I have just this minute found an identical one but from a Touran.
Screenshot_20240617-123338.jpg
Would it be possible for you to adapt this with Odis?

Thanks again

[Crasher]

What is the VIN?

[Twolitrepinto]

Not with the car at the moment. Will post the VIN later or tomorrow when I am.

Thanks