Help - ABS/ECU not communicating

[ivorblueone]

Hi, 2003 1.4tdi Fabia. all working fine until one day my power steering dropped out, along with no speedo, ABS warning etc and other lights.

switched the car off and on again and all good for another 1500 miles. now the same thing again but a hard fault. Engine starts but sounds lumpy and car drives. AA man plugged his diagnostic tool in and it says the ABS is not communicating with the ECU.

i found something online that said broken wires between the ECU and ABS unit are not uncommon. does anyone have any experience of this before i dive in? 

[Breezy_Pete]

Check the ABS fuses in the cabin, and battery-top fuseholders as a first step.

 

Cabin fuse No. 25;

Battery fusebox: strip fuse No. 6 and blade fuse (No. 7) just to the right of strip fuse 6 under a plastic cover.

[ivorblueone]

Great thanks, I will have a look in the morning. 

[ivorblueone]

Checked all the fuses and all fine. Any idea where I can get a decent wiring diagram so I can do some proper checks between AND unit and the ECU? All I have is a rubbish Haynes manual that is as much use as a chocolate fireguard.

Got in to the loom yesterday to check the twisted orange pair that run from ECU to ABS. Nothing untoward looking so far, but will do a few more checks around there today. 

Does anyone know if the speedometer signal is driven by just one of the wheel speed sensors like a range rover? as this may a root cause???

[Breezy_Pete]

There are some wiring diagram pdfs amongst the downloads here: 

I'm not sure which wheel speed sensors are used for vehicle speed calcs, but I think it will be more than just one of them. Possibly all four.

[ivorblueone]

fantastic thanks. -2 and snow outside today, so it will a chilly process done in short bursts around lots of hot cups of tea.

[Breezy_Pete]

Please let us know what you find. 

Best of luck. 🙂

[ivorblueone]

im a bit slow updating this, but now having had all the looms stripped down for inspection and test as far as poss, i concluded it must be the ABS pump module at fault. I sent it of to ECU Testing in Derby for repair and they have confirmed it as a hardware fault with the unit, but are unable to repair it, or supply a replacement. The local skoda garage wanted £1100 for one, and none of the scrapyards have one of the correct part number. As i speak there is one coming from Spain that i found on Ebay for £100 - fingers crossed its a good one.

keep you posted.

[ivorblueone]

On 27/12/2022 at 10:10, Breezy_Pete said:

Please let us know what you find. 

Best of luck. 🙂

Having waited almost 3 weeks for a replacement ABS pump to come from a spanish Ebay vendor, it was fitted and bled yesterday. Works perfectly with no trip to the skoda garage to get it coded to the car. Also had to clear the latched engine faults 18057 and 18061. Happy days (finally)