I have been for a drive at 20mph+ for a few minutes and it still happens the same as before unfortunately.
ABS fault with no fault codes
- Thread starter domlinson
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I have been for a drive at 20mph+ for a few minutes and it still happens the same as before unfortunately.
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- North Shropshire
Purely guessing now, but i wonder if there is no problem, but in fact a dash problem?
I wonder if it's worth disconnecting the battery and removing the dash, check the multiplug connections are ok?
I wonder if it's worth disconnecting the battery and removing the dash, check the multiplug connections are ok?
I've had the dash out already and everything seemed ok 
The reason I had the dash out was because when I bought it I had a weird feeling that an "ABS fault" message should be accompanied with an ABS light, and at the time, it wasn't... Lo and behold, someone had taken the bulb out.
The reason I had the dash out was because when I bought it I had a weird feeling that an "ABS fault" message should be accompanied with an ABS light, and at the time, it wasn't... Lo and behold, someone had taken the bulb out.
Datatek
Well-Known Member
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The message comes via the BECM so check the BECM connectors for corrosion.I've had the dash out already and everything seemed ok
The reason I had the dash out was because when I bought it I had a weird feeling that an "ABS fault" message should be accompanied with an ABS light, and at the time, it wasn't... Lo and behold, someone had taken the bulb out.
Will do that tomorrow, thank you.
Checked all the fuses today and they're fine, so BECM is the next port of call.
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Are you getting a audible tone aswell as the lights
Yes - getting the audible tone at the same time as the ABS fault message.
In addition, I don't know if it was voltage related, but once or twice the message and audible tone were constantly happening every few seconds whilst driving... This made me feel like it was a wiring/connection fault somewhere...
However more recently, the issue just happens at ignition on and then doesn't beep or warn me again... (Apart from the ABS light never going out)
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It could be a wheel sensor then, the first check is the system the second check is for sensor feedback if I'm correct?
A Nanocom showed no faults, and also that all four sensors appeared to have valid voltage readings. (2.31 from memory) so I initially thought the sensors were ok.
How can you diagnose which sensor(s) are at fault?
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Well I’ve you ever solve this problem let me know how I’ve read on the nanocom ecu page and it says I’ve getting audio tone aswell then could be the pump or valves I’ve got the same faults as you have done every test with nanocom separately and all coming back as there readings say they should so can’t see it being the ecu going to check all the pins next but I’m no auto electrician
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You can with the nanocom read the speed sensors behavior upto 5 or 8mph and see how they respond. Over that speed the nano can't track them.
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As the OP's "fault" message appears before any motion of the vehicle (so no waveform pulses/frequencies to compare yet) and all the sensors were showing 2.29/2.3V on my Nanocom when we looked and when a sensor fails you get 0v shown then it rather suggests to me that the ECU should be swapped out as a next step or put the vehicle up on axle-stands and let it idle away in gear at a few MPH while you check live data/speeds from each wheel?
Aha I didn't know that, it would be useful to see the values reported to confirm the wheel sensor states.
Agreed - unless a sensor is outright dead, I don't see how the ECU could determine that it was faulty without the vehicle moving.
I have swapped a 'tested and working' ABS ECU in, exactly the same part number as mine, but it does not make any difference. Behavior is identical
I tested the continuity of the main brake pedal switch today (the three pin one) to check that both of the internal switches were working (one is normally open, the other is normally closed).
If i'm honest, I think there could be something wrong with it... the normally closed side seems fine, buzzes out @ 0ohms when the switch is 'relaxed' and then goes open circuit when the switch is pushed in.
However, the normally open side seems to have something funky going on. Press the switch a little bit and then the circuit is made (0 ohms) but then press it further and it goes open circuit again... seems wrong!
I pulled the plunger out all the way and then reset it back into the mount (with the pedal depressed) and then let it spring out again to set the plunger but it hasn't helped.
Will order a new one of those, as it's cheap insurance.
If i'm honest, I think there could be something wrong with it... the normally closed side seems fine, buzzes out @ 0ohms when the switch is 'relaxed' and then goes open circuit when the switch is pushed in.
However, the normally open side seems to have something funky going on. Press the switch a little bit and then the circuit is made (0 ohms) but then press it further and it goes open circuit again... seems wrong!
I pulled the plunger out all the way and then reset it back into the mount (with the pedal depressed) and then let it spring out again to set the plunger but it hasn't helped.
Will order a new one of those, as it's cheap insurance.
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Very puzzling then. If there are "no faults logged" and the message pops up on start-up where's it coming from?Aha I didn't know that, it would be useful to see the values reported to confirm the wheel sensor states.
Agreed - unless a sensor is outright dead, I don't see how the ECU could determine that it was faulty without the vehicle moving.
I have swapped a 'tested and working' ABS ECU in, exactly the same part number as mine, but it does not make any difference. Behavior is identical
I wonder if your ABS pump hi/low pressure sensors are duff?
My thoughts exactly.
As I see exactly the same outcome with the two ECUs, I'm wondering if there is a wiring fault somewhere and other systems are unable to communicate with the ABS ECU... for example, according to Rave there is a dedicated link between ABS and BECM... potentially the BECM is unable to communicate with the ABS ECU so just throws the light...
Unsure about how I can check that, apart from just checking all the connectors.
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Do you get the 35mph max message on the dash?
Nope, never seen that message before. What would that indicate?
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Sorry, was thinking about the eas relay, but that's for.. er.. the eas
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Well, if the ECU has been swapped out, and the brake switch looks "iffy" that's a cheap thing to change (but I thought it was more to do with the Cruise/Control than ABS).
The High/Low pressure switch has been known to fail on the ABS. I have seen a few threads on forums about it.
Good Luck!
The High/Low pressure switch has been known to fail on the ABS. I have seen a few threads on forums about it.
Good Luck!
