Error codes U0121 & U0126

[Jon T]

So I have had an intermittent problem with my 62 plate XF Sportbrake 2.2d 200ps.

I will go to start the car and get a continuous bip bip bip, faults come up on the display, ABS Fault, park brake fault (there maybe others) and the car doesn't start. Take my finger off the start button and it just shuts down but the continuous bip stays.

I have read the codes with my code reader, and cleared them, which are U0121 Lost communication with ABS control module & U0126 Lost communication with steering angle sensor module.

The car has a brand new fully charged battery fitted.

Has anyone else had this issue? Does anyone know what the problem is and how to fix it?

Many thanks

Jon

[Bill C]

I have been getting PARK BRAKE FAULT, GEARBOX PROBLEM, DCS NOT AVAILABLE for about 3 years on my 20103,0D and more recently WATER IN FUEL. The faults clear themselves and return some days later but the car drives perfectly - so i ignore them, although they are annoying. I have fitted a new battery 6 months ago and going to get some further investigation done next month.

it’s obviously a sensor/software issue and i i find any further info, i will report back.

bill

[Jon T]

2 minutes ago, Bill C said:

I have been getting PARK BRAKE FAULT, GEARBOX PROBLEM, DCS NOT AVAILABLE for about 3 years on my 20103,0D and more recently WATER IN FUEL. The faults clear themselves and return some days later but the car drives perfectly - so i ignore them, although they are annoying. I have fitted a new battery 6 months ago and going to get some further investigation done next month.

it’s obviously a sensor/software issue and i i find any further info, i will report back.

bill

I had all those faults come up on mine. I bought a new battery, fully charged it and then fitted it. That sorted those faults out for mine.

This is a different problem I'm having now. Very annoying when you're in a car park and your Jaguar doesn't start lol

[Big John]

Hi Jon

Have the current problems appeared since the battery change? It sounds to me like some of the modules have had their software corrupted. It might be worth looking on here for a thread about a company which I think was called EE in the midlands who use the Autologic diagnostic software. They seem able to reocde modules with much greater success (and cheaper) than JLR main dealers! Can't hurt to give them a call.

John

[Jon T]

I had error codes come up before the battery change. The first time the car wouldn't start I was at work and had to call the RAC out who put his jump leads directly onto the battery terminals, even after I said he shouldn't put the negative directly onto the battery but onto an earth. He was pretty crap to be honest, told me the battery was fine and said it looked like water got into the ECU. I have check this and can't see how water could get into it, all looked fine when I removed it. New fully charged battery resolved this issue.

I had to take it to CFS Motors in Corley who reprogrammed the central locking and keys for me as removing the battery had lost these. I just need a new rear left door lock actuator now lol

[Bigvic]

These codes are classic battery problem codes.

Did you tell the battery monitoring system that you have a new battery?

[Jon T]

1 hour ago, Bigvic said:

These codes are classic battery problem codes.

Did you tell the battery monitoring system that you have a new battery?

How do you do that? I would have thought after driving the car for nearly a month the monitor would have sorted itself to be honest

[Big John]

Hi Jon

I presume you have checked that you do not have a swimming pool in the spare wheel well. My Sportbrake had that before I bought it. I does cause these sorts of problems.

John

[Bigvic]

Good idea to check for water in the boot too

[Jon T]

1 hour ago, Big John said:

Hi Jon

I presume you have checked that you do not have a swimming pool in the spare wheel well. My Sportbrake had that before I bought it. I does cause these sorts of problems.

John

Yes I have checked for water in the boot. Also checked for water on the fuse box in the drivers footwell. Nothing to report there

[Chalkygaz]

Did you get the problem resolved i have got exactly the same issues?