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[andyc]

Ok so the ABS light has been coming on, going off, not coming on at all or staying on all the time. First throught was the N/S/F hub as that is the wheel that picks up the vehicle speed for the ABS.

Plugged Tech2 in the other day just tp make sure and there are no TC's listed in the ABS ECU which was a bit odd as the abs light was on at the time. Had a play around with Tech2 and found the TC's in the engine ECU with TC P500.

Took the car up the road with live data running and all four wheel sensors were giving the same reading which to me points away from the left front hub.

Done some checking between the ABS ecu & the Engine ECU, all fine and ever checked the brake switch as it also has P0157 logged as well.

Anyone one else got any idea?

Cheers
Andy

[TheBoy]

In the case of (post 98) Omega ABS, the ABS light on but no TC is a sign of a shagged ECU.

Via Tech2, go into ECU Control (I think) and there is a function to test if the Telltale (dash) light is working. If the light is on, when the ECU thinks its off, it does point to ECU.

In pre 97 Omega ABS, esp the non TC variant fitted to 2.0l, there is a relay that seems to stick, which throws a code. A gentle idioting with a screwdriver handle is a temporary fix I've used to prove it....  ....in both times I've seen it, AFAIK, the owner never did anything, and the fix stayed more permenent 

[2woody]

try putting a multimeter across the sensor output and then spinning the wehhl as fast as you can. Repeat for all four wheels and compare.

remember to be on Volts - A.C.

I've seen a few different systems give enough of a signal to generate a live data trace, but not enough to allow the ABS system to work fully.

[andyc]

I'm thinking is the ABS ECU. The TC light doesen't come on at all , not even when you turn the key to get all the dash lights on.

Although the other night driving in town the ABS light was on but as i slowed for red lights there was a clunk, the TC light came on and after a few seconds both the ABS & TC lights went out, was a dry road and slowing from around 25mph.

My tech is printing up all the protocols for P0500 so i'll be running some more checks over the weekend.

In the mean time we have had an Astra G traded in that doesn't owe alot of money and it has the same system plus engine an box are the same, might take a punt on that strip it of all the good parts and weigh the rest in

Cheers
Andy

[Marks DTM Calib]

When checking the live data are all the speeds shown for the wheels exactly the same in a straight line or is one 2-3 mph lower.

Hvae seen one or two where the relucter rings are goosed on one corner and you get the above effect

[andyc]

Same speed when in a straight line