I have here in front of me a 1988 XJS with an ABS light on. When I placed the car in to diagnostic mode the fault code that was displayed was 32 (3 flashes then another 2), indication the front right wheel speed sensor is at fault to some degree. No according to the factory manual the ECM believes there is a either too high of a resistance in the circuit or its open circuit.

Ive done a resistance check across the front wheel speed sensors and found both sensors came back the same 1.1 k ohms. I then ran a continuity test across the earth and the signal wires, again for both sides and both came back the same and with in spec. I then did a resistance check across the two wires at the ABS ECU plug with the sensors plugged in and they too came back ok.

At this point I started testing the powers and earths of the ecu and all came back ok. I then swapped out the ECU with a known good one and it too came up with the same code. I checked for resistance across the sensor plug to the loom and was 0 ohm. I then changed the wheel speed sensor out of another car (did not flag any codes when installed in the car it was removed from) and it did not change anything.

Im getting to the the point that I'm about to poor a 25L of fuel over the car, lighting it and walking away. Any ideas?

 

25 litres seems a lot!

 

You can come and do mine as well while you are about it!

Got another massive problem on my hands

See the next Post in my 'Cherry Blossom' Restoration Thread

 

Did you manage to get this sorted? I’ve the same problem, front right. Not swapped it out yet though.

 

Fynn,

A naive question maybe, but did you clear down all the codes with the replacement sensor installed and then do the test again?

Paul

 

Clear as in how? When I swapped the ABS ECM a disconnected the battery and rouched the pos and neg together with the ignition on. Ive driven the car a few Ks up the highway to see if it might clear or even flag any other codes.

When placed in diagnostic mode it only gives the flash code for 32, no matter what ECU or wheel speed sensor intalled.

 

Ive found that the ignition power to the ABS ECM is intermittently droping out. Traced it pack to the ignition switch to find high resistance and a dodgy inline fuse soldered in.removed and disassembled the switch and found it had gunked up. So I cleaned it and put the thing back together and tested 0 ohms arcoss the contacts. Also repaired the average wiring job. Now get a nice battery voltage at the module but it seem the ECM has had too.

Swapped in another ECM that I could get to go in to diagnostic mode and now gives me a flash code for 21, valve body. Will check for shorts or high resistance and will report back.

 

I would pay money to be able to do this kind of electrical troubleshooting... I don't know why,,, just not made this way.

Amazing work! Amazing clear description. Thanks for sharing.

 

He hasn't solved it. We can all do that 😆

 

How do you get abs codes? I should know but.

 

It is fairly easy. In the boot on the left hand side up on the wheel arch is the abs ecm. As part of the thick wiring loom feeding it there is attached a plug with 3 wires. Make a short connector wire and link the pink/ brown wire to the black one. ( ignition off). Then get in the car and turn the ignition to on without starting the engine and watch the dash. The abs light will blink to indicate the numbers of any codes. Keep watching for several seconds as there may be more than one code.

 

Thanks brinny - I managed to get a list of the fault codes in the blink test and my garage man has kept them. where can I get a copy?