Technical ABS/EBD very inconsistent error

[Mauro Malvezzi]

Hi everyone,

I finished reading all the threads concerning the infamous ABS/EBD fault that I could find on the forum. My second multipla, which I bought a month ago, had its ABS pump replaced by the seller on my specific request before the sale was final. This was done in order to cure a faulty ABS (wheels cross braking/improper ABS function). Just before the purchase, the car passed MOT.

After driving it for 3 weeks, a very strange ABS/EBD fault started popping up. I'll list when and how the fault happens below:

1.Rough/bumpy road, but sometimes it's each and every damn bump that triggers the fault, sometimes nothing happens
2.Turn to the right (rare)
3.Standstill, random timing
4.Only ABS fault
5.Only EBD fault
6."ABS-EBD light" fault

Some days I get by with just 1-2 occourences, some days it drives me crazy, beeping every half a minute 5 times in a row.

On a flat-ish road (e.g. motorway), the rate sharply decreases.


Any help is greatly appreciated

 

[jackwhoo]

You need to connect to abs ecu and read fault codes to get some clues to actual fault.

 

[jackwhoo]

Plus tell us what year car made
Total kms

 

[Mauro Malvezzi]

Will connect via MultiECU tomorrow;

Year: 2002
Kms: 279000

Series 2

168A8000 Engine (JTD 115 CV)

 

[Mauro Malvezzi]

Looks like I counted my chicken before they'd hatched. My OBD2/ELM module is not suitable for testing the ABS control unit, I need the VAG/KKL adapter. I'll update the thread as soon as I get my hands on one

 

[MultipleMultis]

Connections in the rear door areas, you remove them to do work on rear axle and hubs, worth checking wires not broken.

I replaced my front ABS sensor a couple of years ago, it comes to top of the strut area and there is a connection block there. Worth checking if any issues with the physical wires and/or sensor.

 

[The Panda Nut]

It does sound like a loose connection or damaged wire might be the cause and something strut mounted makes sense Difficult to see if a pin is not tight enough. I hope MES get you going in the right direction. Good luck

 

[MultipleMultis]

ABS Wheel Speed Sensor - Front - RH - fits Fiat Multipla (186_) 1992-2010 | eBay UK

Fiat Multipla (186_). ABS Sensor. VXPRO components are protected by a market leading warranty of up to five years (excluding labour.). We are always help you to have a 100% positive happy buying experience.

www.ebay.co.uk

I used this part for front
I think another one was too short ? Be careful on length of cable ...

 

[Mauro Malvezzi]

End of year update - and thanks in advance to those who already replied.
I was able to connect to the ABS ecu. Took a bit of fiddling, but finally managed to do some tests.

On the up side: every test available via MES was completed successfully. The ABS seems to be in working order, I gather.

On the down side: MES does not detect any fault code. Moreover, the software seems to kick itself out of connection after a few minutes, and connection while the vehicle is moving is not possible at all (I do suspect, however, that this is by design).


Abs/ebd fault light still coming on when driving over bumps/rough tarmac.

Happy New Year , everybody!

 

[jackwhoo]

End of year update - and thanks in advance to those who already replied.
I was able to connect to the ABS ecu. Took a bit of fiddling, but finally managed to do some tests.

On the up side: every test available via MES was completed successfully. The ABS seems to be in working order, I gather.

On the down side: MES does not detect any fault code. Moreover, the software seems to kick itself out of connection after a few minutes, and connection while the vehicle is moving is not possible at all (I do suspect, however, that this is by design).


Abs/ebd fault light still coming on when driving over bumps/rough tarmac.

Happy New Year , everybody!

The free mes is time limited.
It should not disconnect while driving.
You should be able to graph each wheel speed while driving and see if the dash fault message corresponds with a faulty speed from one wheel.

 

[Mauro Malvezzi]

Graphing each wheel is possible - I did that by connecting to the ECU while standing still, and then driving a short distance. All 4 sensors read the same, but I am not able to check for faults because MES won't stay connected for a long enough time - disconnection takes place long before the free version timeout.

Connection to ECU via KKL cable/switch on Pin 1 without green adapter (wouldn't work otherwise!)

 

[The Panda Nut]

Graphing each wheel is possible - I did that by connecting to the ECU while standing still, and then driving a short distance. All 4 sensors read the same, but I am not able to check for faults because MES won't stay connected for a long enough time - disconnection takes place long before the free version timeout.

Connection to ECU via KKL cable/switch on Pin 1 without green adapter (wouldn't work otherwise!)

Maybe because of a fault. Check for earthing issues.

 

[Mauro Malvezzi]

Maybe because of a fault. Check for earthing issues.

This might very well be. Sometimes vibration (either rough tarmac or engine) makes the ABS/EBD lights go crazy. Any pointers to where I should start looking? I do have the workshop manual for the first series multiplas.
Thanks and happy 2026!

 

[ceecff]

ABS working (pedal vibration) on bumps or big jumps happens in Lucas units, different cars, but it must not cause permanent error. In that case check well ecu wiring, tyre sensors and pedal brake sensor.
You can graph-log all 4 ABS sensors at low speed with MES + KKL FTDI + normal or slow kwp2000 timming + COM delay 2-6 ms depend on PC. ELM327 must work the same.

 

[Mauro Malvezzi]

ABS working (pedal vibration) on bumps or big jumps happens in Lucas units, different cars, but it must not cause permanent error. In that case check well ecu wiring, tyre sensors and pedal brake sensor.
You can graph-log all 4 ABS sensors at low speed with MES + KKL FTDI + normal or slow kwp2000 timming + COM delay 2-6 ms depend on PC. ELM327 must work the same.

Hi,

thanks for chiming in. ABS seems to work fine - on board diagnostic tests activated via MES confirmed that. Bumps oder engine vibrations cause intermittent activation of ABS/EBD fault lights, but it is all momentary - fault disappears instantly, after beeping two or four times (depending on whether the fault is EBD only, or EBD+ABS)

 

[Mauro Malvezzi]

Update!

The Panda Nut was right. Exasperated by the beeping, I randomly checked all the wires I could lay my hands on in the engine compartment. One of the smaller wires that connects via an eyelet to the negative terminal of the battery was completely loose. I tightened the nut down, and the issue disappeared.
I will add pictures of the culprit later in the day

Case closed!

 

[jackwhoo]

Fantastic news , thank you for update .
I have seen the small ground wire to battery terminal on my multipla and now know what may happen if becomes loose.

Best wishes
Jack

 

[Mauro Malvezzi]

As promised - picture of the culprit