ABS light not coming on

[figozz]

Hi all

I am new to Hyundai ownership and this forum.

I have a Hyundai Santa FE 2.0 TD (2001)

Car just failed its MOT on a few things. Ball joint, bulb and most concerningly ABS light not coming on at all.

Does anyone know what might be causing this? I am being led to believe it could be a faulty ABS ECU.

Could it possibly be anything else? Could it be a faulty bulb/led in the instrument panel? If yes, how easy is it to check and replace this?

Also, would a faulty/damaged ABS wheel sensor ring cause the ABS light to come on and/or would it generate an error code in the ECU?

I have had a mechanic plug a diagnostic unit in and he said that there were 6 undocumented error codes on the ABS ECU. However I dont know what the coders were and he reset the ECU and they didnt seem to return.

Only reason is, one of the wheels seems to be activating ABS inadvertently when braking (even lightest of braking). Could this be an ECU fault or is this purely either ring or sensor fault?

Thank you for any assistance you can provide with this problem.

[Ruperts Trooper]

If it's a recently purchased car, I'd guess the ABS light has been disabled to hide the ABS fault, which would have been a MoT test failure anyway.

You need to do several things - get the warning light problem identified and corrected - retest the ABS ECU for fault codes and have them properly recorded - check that all your tyres are the same size as differences can confuse the ABS.

[figozz]

Originally Posted by Ruperts Trooper

If it's a recently purchased car, I'd guess the ABS light has been disabled to hide the ABS fault, which would have been a MoT test failure anyway.

You need to do several things - get the warning light problem identified and corrected - retest the ABS ECU for fault codes and have them properly recorded - check that all your tyres are the same size as differences can confuse the ABS.

Yes, I do believe the ABS was disabled to hide the fault. The 2 ABS fuses were removed, and I didnt realise until at least 6 months after purchase that this had occured. I feel conned and very disappointed. However I am stuck with the car now and I either need to try and get it repaired as cheaply as I can or move the car on again and buy a new one, depending on how economically viable it is to repair.

However, even after replacing the 2 fuses, the ABS light still doesnt come on at all. So I am worried that the bulb/led could have been tampered with in the instrument panel.

The ABS ECU was retested and no further faults seem to have occured.

The ABS does work, albeit this seemingly one wheel intermittently activating ABS (without cause) when braking. It seems to be a common problem and this is more than likely a faulty ring. My question is, would a faulty ring cause an ABS light to stay on. Therefore would this give the seller cause to disable the light somehow (as well as removing the fuses which clearly turns the ABS off as a whole).

Likewise, would removing the fuses cause the ABS light to stay on, again giving cause to disable the light?

How easy is it to replace the bulb/led for the ABS light?

I am considering all options at the moment, but I really could do with some advice from someone with a bit more experience with the car because at the moment all I have to go on is what limited information I can find on the internet.

All tyres are exactly the same size. Near enough same tyre albeit slightly different model. Rears are Goodyear Wrangler AT/R and fronts are Goodyear Wrangler AT/SA

I worry what else I dont know about has happened to this vehicle. I now worry if the mileage is correct, because if someone has tampered with the ABS light, how easy would it have been (having reached that point) to replace the clock? I fear I may have bought a ringer... the front fog lights were missing which I didnt realise at the time were standard on all models. A makeshift wire mesh had been put in their place. Already had to replace PAS lines as they were corroded.

Thanks again.

[Ruperts Trooper]

Having now failed an MoT test I don't see you have any alternative but follow through and get the ABS fault fixed.

The ongoing issue may be as simple as a faulty ABS ring or ABS sensor.

Check out the UK Hyundai Owners Club forum as well which may help Forum message

[figozz]

Originally Posted by Ruperts Trooper

Having now failed an MoT test I don't see you have any alternative but follow through and get the ABS fault fixed.

The ongoing issue may be as simple as a faulty ABS ring or ABS sensor.

Check out the UK Hyundai Owners Club forum as well which may help Forum message

Indeed it may well be just a faulty sensor or ring all along. But my concern is to what extent has tge previous owner gone to hide the fault.

Clearly one of the steps was to remove the ABS fuses. But my question is, would doing this make the ABS light stay on or go off. If it makes the light stay on, then the previous owner would have needed to take further action in order to hide the error light. Does this mean they disabled the light from behind the dash or could this be achieved another way?

[paul03]

I cannot imagine removing fuses will provide for an indicator to light up.
It removes voltage so no indicator.
I suppose the fuses were removed to hide the incapabillity to correct the underlying fault, or the costs for repair were to high.
What were the 6 undocumented error codes. Undocumented to my opinion are codes Hyundai specific, like numbers above P1000.
They are, however, certainly documented by Hyundai.
So which were these numbers?
When you want to check the instrument light bulb, simply remove the instrument cluster with 2 screws in the top lining.
Gently pull out the cluster, to the top, there are wires attached at the rear, which you can undo and put back later. You cannot mix them up, they only fit their socket.
Then look at the circuit board at the indicator position.
The bulb can be easily removed at the back by turning it, a bajonet fitting.
Then you can check for function, or replace if broken.
You could interchange it with some other bulb of the cluster to see if it functions.

Greets,
Paul

[figozz]

Good news!

I pulled the instrument panel out (which luckily was very easy) and a previous owner had indeed pulled out some bulbs from the instrument panel to hide the ABS fault.

The ABS, Brake and TCS bulbs had been removed. I tried a working bulb from one of the other lights and sure enough (with the 2 x ABS fuses in the fusebox under the bonnet removed) the ABS and Brake light were permanently on.

After replacing the ABS fuses, the lights operated normally.

Still though was the problem with the ABS activating under low speed braking (under 15mph). As I suspected, this was the original fault (a broken tooth on the ABS Senson Ring) and a replacement CV joint fixed the issue. Got a friend (local mobile mechanic) to do this for me and it only cost £50 for the part and £30 to fit. I could have just replaced the ring, but it's quite a big job to clean up a CV joint ready to fit a replacement ring, and after seeing the joint that come out, it was in quite a bad way and I am glad I replaced it.

Cheap fix in the end. I cant believe someone would go to such extent (and rendering a car less safe than it's supposed to be) to hide such a simple problem.

If I have learnt one thing, it is that I will check for these things next time I purchase a used car.

Thank you all for your advice.