ABS & TC Lights

[Def90]

Interested to know if anyone has come across this issue before and what possible solutions might be.

I have recently upgraded my 300tdi 90 to a TD5 110 - Excellent truck, but have noticed that sometimes the ABS & TC light will come on, on the dash console. When I stop and switch off the engine, the fault obviously resets itself and when I switch the engine back on the fault is cleared and all back to normal.

There is no particular circumstance when or where the light come on, some days I can drive for 100's of miles and never see it, other days it's on within miles of leaving home. I had first thought it was triggered by water, but now the weather is drying up, I still get the same issue. Neither before, during or after the lights have come on do I seem to get any mechanical problems related to the brakes. So I'm puzzled at what to do next.

Do I book it into a dealer for them to diagnose the issue and pay the big bucks for them to fix or is their some simple steps I could take to check things out before falling back on the dealer?

Any Help appreciated

[dxmedia]

Unplug each of the ABS sensors on the hubs and check of impedimence (check the resistance).

If they are all exactly the same (give or take a tiny bit) make sure that the tone rings are clean (wire brush) and the teeth aren't jammed with anything.

Check all the plugs for the abs sensors, make sure that they are clean and the contacts are good, and check for any frayed wires.

Oh it 1 of the sensors has a value totally different to the rest - thats your problem.


That's 90% of abs issues on any car solved in that lot.

[Def90]

Thanks for the quick feed back - How should I check the impedance? - Is it simply a matter of unplugging the sensor cable and putting a meter across the two ends of the cable?. It had crossed my mind to unplug each sensor in turn and drive the truck and see if the issue goes away - in that way identify the sensor/corner that of the truck that had the issue, but I didn't know whether unplugging a sensor would cause issues or cause the truck to become unsafe when driven?

[dxmedia]

Yeah just stick a mulimeter across the plug and check the ohms - you might need to play with the scale on the multimeter to get it to NOT register a 1, start low and slowly turn the dial up.

If you just unplug one sensor you'll get an abs light come up due to the system failing a self check.