ABS Problems/Diagnostics
Discussion
Hey guys,
Recently had front right wheel bearing replaced on a Honda Jazz 2004, now the ABS light has come on. Mechanic told me it was probably the sensor, which I had replaced but the light was still on.
Took the car in for some diagnostics, and the 2nd mechanic told me the pump/modulator had failed. I've now had the pump replaced, but the light is still on!
Bought a cheapish diagnostic tool to try and figure out what was wrong, and the error showing is for the front right pulsar (sensor?) Cleared the code and the same code comes back up.
My gut feel is that the guy who fitted the bearing has messed it up. Having done some research, the ABS has a magnetic ring built into the bearing, which is picked up by the sensor. This has to be installed the right way round for it to pick up, so either it's in the wrong way round, or he's damaged something in the process.
I'm reluctant to take it back to the first mechanic as he obviously fobbed me off and I just don't trust him.
Question - using the diagnostic tool, I can see the right and left ABS sensors returning a wheel speed whilst driving. Would this be the case if the bearing was installed the wrong way?
When i reset the code and drive, I can feel the right brake catching before the ABS disables.
Any other suggestions? Car is out of MOT, so not too keen on driving it around at present. If anyone can help/advise that would be very much appreciated! Based in Watford if anyone is local!
Recently had front right wheel bearing replaced on a Honda Jazz 2004, now the ABS light has come on. Mechanic told me it was probably the sensor, which I had replaced but the light was still on.
Took the car in for some diagnostics, and the 2nd mechanic told me the pump/modulator had failed. I've now had the pump replaced, but the light is still on!
Bought a cheapish diagnostic tool to try and figure out what was wrong, and the error showing is for the front right pulsar (sensor?) Cleared the code and the same code comes back up.
My gut feel is that the guy who fitted the bearing has messed it up. Having done some research, the ABS has a magnetic ring built into the bearing, which is picked up by the sensor. This has to be installed the right way round for it to pick up, so either it's in the wrong way round, or he's damaged something in the process.
I'm reluctant to take it back to the first mechanic as he obviously fobbed me off and I just don't trust him.
Question - using the diagnostic tool, I can see the right and left ABS sensors returning a wheel speed whilst driving. Would this be the case if the bearing was installed the wrong way?
When i reset the code and drive, I can feel the right brake catching before the ABS disables.
Any other suggestions? Car is out of MOT, so not too keen on driving it around at present. If anyone can help/advise that would be very much appreciated! Based in Watford if anyone is local!
It is possible whoever changed the bearing did also cause the problem...or sometimes damage can just happen during such work with seized parts etc.
But also, often too, aftermarket parts are just crap and will cause problems, whereas OEM parts, albeit more expensive, just work every time.
But you'd need to log all wheel speeds and see if there are any anomalies with that one corner that would also point you in that direction vs codes alone.
You seem to say it does read speed...so it must work to some degree...so presumably takes a little driving before the light comes on ? vs a hard fault with the light permanently on from key on ?
But also, often too, aftermarket parts are just crap and will cause problems, whereas OEM parts, albeit more expensive, just work every time.
But you'd need to log all wheel speeds and see if there are any anomalies with that one corner that would also point you in that direction vs codes alone.
You seem to say it does read speed...so it must work to some degree...so presumably takes a little driving before the light comes on ? vs a hard fault with the light permanently on from key on ?
The ABS ECU looks for certain things from the wheel sensors.
1. A defined resistance (usually a couple of 00 ohms) to say that there is a circuit through the sensor coil.
2. A speed reading to say that the wheel is moving.
3. A speed reading s to the other signals from the other sensors.
If the warning light clears after switching off/on it could be 2 or 3 but not 1 as this is the first check the system does.
If it comes on immediately you move it could be 2 is not happening.
If it comes on after a certain speed it can simply be one/more tyre/wheel combination is incorrect & as it gets above a certain speed the difference is too much for the system.
The above is a generic scenario & some do differ of course.
Based on what you say if I understand you correctly you have changed the sensor that is indicated as correct & that made no difference.
It is therefore likely that if your light never goes out & if you have changed this sensor then the wiring/plug is the actual issue.
You need to get a pin-out for the ECU & measure the resistance of the sensor loops & find the difference.
1. A defined resistance (usually a couple of 00 ohms) to say that there is a circuit through the sensor coil.
2. A speed reading to say that the wheel is moving.
3. A speed reading s to the other signals from the other sensors.
If the warning light clears after switching off/on it could be 2 or 3 but not 1 as this is the first check the system does.
If it comes on immediately you move it could be 2 is not happening.
If it comes on after a certain speed it can simply be one/more tyre/wheel combination is incorrect & as it gets above a certain speed the difference is too much for the system.
The above is a generic scenario & some do differ of course.
Based on what you say if I understand you correctly you have changed the sensor that is indicated as correct & that made no difference.
It is therefore likely that if your light never goes out & if you have changed this sensor then the wiring/plug is the actual issue.
You need to get a pin-out for the ECU & measure the resistance of the sensor loops & find the difference.
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