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Hi Les, yes, the autoranging DVM is a wonderful thing, but I personally don't like them and prefer a standard type, I also use an analogue AVO meter as a weapon of choice too.

It's been a while since I've had to replace a sensor on a Carlton (Omega A), so my findings are from memory, but I seem to think that the output is in several volts, rather than just fractions of a volt, although it would certainly depend on how fast you can spin the wheel. The other point is the fact that my findings are from the system used on the Carlton and not the Omega B, so there may well be significant differences between the two that I'm not aware of.

I've had to replace a few ABS sensors over the years on Carltons, but they were always found by doing a resistance check with a meter set to an appropriate ohms range and faulty ones were always found to be open circuit. It was only on the most recent time that I had a sensor fault where I found that after replacing two open circuit sensors that I still had a fault, ie, light going out, but coming on again after driving off, that I had to resort to measuring the actual output that showed a sensor that although indicating the correct resistance in ohms, actually had very low output when tested with a DVM and a wheel spin and compared with the other good sensors regarding their output.

You're tempting me to pull the battery on a Carlton, pulling the ABS module plug, connecting a meter and jacking one corner to spin a wheel to confirm the voltage output, however, it's going to be raining for the next few days, so probably not just for the moment.

I hadn't appreciated what actual manual you had for your car, so it looks like you're going to have to search for your ABS ECU. I'm actually very surprised that someone whose actually owned an Omega B in the past, hasn't chipped in with information as to where the unit is actually situated on your particular car.

It may be that the ABS system on your car is significantly more complex than the earlier cars. There certainly is a distinct lack of specific information regarding ABS faults on these cars and I think a lot of this is due to the fact that a lot of people find it very difficult to fix certain problems with these systems when they crop up. Seeing the lack of availability and the price if they are, of the sensors, would lead me to believe that this type of fault has probably lead to the final demise of quite a few of these cars over the years and had them ending their days being dropped into the crusher.
 

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Discussion Starter #22
Hi, Agree with everything you say, I also keep an old Avo 8 as back up, no silly readings when there is really no input. I am also surprised that no one has popped up to tell me position of ABS computer. The computer by the battery for example bears no resemblance to other Omegas I have owned.
I now have success in that the new code reader agreed front wheel and successfully reset code and it stayed OK on the test drive round the block. I think I have learnt the following, It is possible the computer will clear itself for a short time fault, ie where I replaced quickly with the Vectra sensor, the computer saw approx. 1.6K Ohm and reset only to re appear when sensor did not produce enough output on turning. where more recently the fault has been on a couple of weeks you need a decent code reader to reset. This might mean that the cavalier sensor might have worked if I had had the better code re setter sooner. I think both Cavalier and Vectra sensors were suspect in that they were only producing 150 to 180 millivolts. The old and the new sensors on front wheel are both approx 1.6 K Ohms and produce 450 to 480 Milli volts AC on slow rotation and seem OK. I put this in and trust it might help anyone with Omega B . The Vectra sensor turned out to be a Chinese copy the Cavalier sensor was second hand so may also be suspect. I still think it possible they should interchange.

Thanks for interest and suggestions and I agree its a shame these go to scrap prematurely. I have owned Carltons and Omegas both 4 cylinder and 6 and this 2.2
4 cylinder which is basically the 2ltr engine stroked has that bit more torque which is quite good. I think all the Range from Carlton to Omega were very under rated. Thanks and fingers crossed remains OK.
 
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