ABS wiring

[jackherer]

I'm trying to put the ABS light out on my friends 2000 X reg Clio II RS 172, reg X459 DYB which seems to have been owned by a few members on here in the past.

The ABS light was on when he got the car so I don't know all the history.

I read the fault codes and the only ABS code is showing a dead offside front sensor. I replaced the sensor and the fault persisted. The new and old sensors both work fine on the nearside so I am sure the sensors aren't the cause of the fault.

Autodata and the Haynes manual both have wiring diagrams for the ABS and both show the OSF sensor going to pins 3 & 5 of the ABS controller. I checked for continuity from the sensor connector in the wheel arch to the relevant pins and pin 5 was fine but there was nothing to pin 3. Thinking I'd found the fault I unwrapped the wiring loom and discovered two lengths of wire spliced in with solder that didn't look too good but did seem to be connected. I removed them and spliced some new wire in with solder sleeves but this didn't solve the fault and there was still no continuity between the sensor and pin 3 on the controller plug.

At this point I took the back cover off of the ABS controller plug and I found that the wires from the offside front ABS sensor actually go to pins 4 & 5 (not 3 & 5). There is a rear ABS sensor connected to pins 1 & 3 and this works fine so it seems that both the Haynes manual and Autodata have the same error in their wiring diagrams, this seems unlikely to me? Does anyone have a pin out for the ABS controller that shows the OSF sensor going to pins 4 & 5?

At this stage I definitely have continuity between the (tested & working) sensor and the controller but the fault persists so there must be something else going wrong but without a wiring diagram that corresponds to the car I am not sure what to do next. The wiring has definitely been messed about with so I guess it is possible someone swapped some pins over on the ECU connector but it seems unlikely and it isn't as simple as swapping the sensor to where the diagram shows as one of those pins is in use by another sensor that is working.

 

[Ads29]

What's the condition of the pick up ring on the cv joint? Assuming Ph1's use the same system as ph2's

 

[jackherer]

It looks OK and the fault code returns without even moving the car and I don't think it could detect a fault with the ring until the wheels turn.

 

[JB21]

Are the lights on the dash solid with just the ignition or do they come on after a few seconds after start up or on the move?

 

[Ads29]

Stupid question but fault code has been erased? And then it returns?

 

[jackherer]

The lights turn on immediately and solidly and the fault code returns as soon as I erase it.

 

[JB21]

By what you've said it seems like it will be the loom/harness from pump (CPU) to the front sensors if it's been bodged. Saying that I've had a CPU failure before so could also be that. Maybe best getting your mate to get the car hooked up to CLIP to rule out a CPU failure, then if it's not see if you can get a loom/harnesses from someone breaking a 172.

 

[jackherer]

I'll get an oscilloscope on it tomorrow to see if the signal is actually reaching the controller plug intact, it's only two wires so if the signal isn't getting that far or is distorted I'll cut it all out and replace it with new wire all the way end to end.

The problem I have is the connections on the car not matching two different wiring diagrams, has anyone else come across this? Is there more than one type of connector used on different years maybe? I did try setting Autodata to a year or two earlier and later than 2000 but it shows the same pinout, and the Haynes just has one diagram for all years.

 

[jackherer]

This is the wiring to the controller plug, the top row of pins start with 1 on the left and these are the connections I'm seeing:

1+3 offside rear sensor
4+5 offside front sensor
6+7 nearside front sensor
8+9 nearside rear sensor

Haynes and Autodata both say:

1+2 offside rear
3+5 offside front
6+7 nearside front
8+9 nearside rear

 

[JB21]

There's definitely different ABS pumps so would presume there's different wiring plugs.

 

[jackherer]

I've been looking at Autodata again and it does actually have variations on the diagram for different ages of car, they're on some tabs that I missed earlier.

However the diagram I was looking at is for models made up to May 2000 so it should match the car, the next one covers June 2000 to March 2001 and while it is slightly different in some ways the connections to the sensors are on the same pinouts as the first diagram. The last one is March 2001 onwards but it is very different and doesn't apply to this car.

 

[bloke]

autodata wrong? you'll be telling us the tooth fairy doesn't exist next :wink:

autodata is far from perfect. get it on clip, look at live data and take it from there.

 

[bloke]

will see if i can find my wiring diagrams and get the abs for you but don't think i've got them at home.

 

[jackherer]

Thanks. I've looked at the live data on my snap on solus pro and I can see wheel speeds increase when I spin the three good wheels but nothing when I spin the offside front.

 

[JB21]

Thanks. I've looked at the live data on my snap on solus pro and I can see wheel speeds increase when I spin the three good wheels but nothing when I spin the offside front.

A solus pro told me I had a duff NSR sensor as live data was reading 2000kph on a live data run, all the other 3 wheels where reading correct speeds. I spent £120 on the sensor which didn't work, then changed the loom and that also didn't work. Turned out to be an ABS CPU fault in the end once put on CLIP.

 

[jackherer]

I read your thread saying that when I was searching actually. You can't blame the solus for that IMO, I hate to say it but that is operator error really, if it is showing an impossibly high speed it means a high frequency signal is leaking in somehow, it can't possibly be caused by a sensor fault. All it can be is external interference or a signal already in the controller bleeding over.

This car is showing zero KMH on one corner so there is no signal at all.

I do agree that manufacturer specific software is always the best solution but if you work on more than one type of car there is nothing wrong with something like a solus as long as you think through the implications of what it is telling you which admittedly takes experience.

I haven't had time to get the 'scope on this car yet but I'll keep this thread updated when I do.

 

[MicKPM]

Sorry for the poor image but our screens refresh rates are designed to stop this s**t.

The O/S/F sensor is component '152' so pins 3 and 5

 

[jackherer]

Thanks for that. I was hoping it would be different to autodata but it is probably where autodata actually got their info in the first place. I wonder if a mistake has been duplicated by autodata and haynes? Has anyone actually checked the continuity of their abs sensors and found the diagram to be wrong? (or found it to be right for that matter?)

 

[Emad Yehia]

My Clio mk2 model 2004 1.4. 16 v. Show fault both rear abs sensor and I replaced both of rear sensor and both rear rings but still abs not working and show rear abs sensor and we put the car on clip and test speed for front wheels and rear wheels we found in front speed ok and rear speed zero and also checked rear sensor wiring is good and we replaced the pump but abs still not working

 

[Ads29]

Have you checked the main wiring connector underneath the car? It's by the front subframe support brackets

 

[Emad Yehia]

Have you checked the main wiring connector underneath the car? It's by the front subframe support brackets

Yes and we checked segnal from rear sensors is working and I replaced rings and sensors and pump and main master but still not working

 

[Ads29]

Have you continuity checked all the wiring for the ABS? Personally I'd do it between each connector rather than at once (assuming you haven't already)

 

[Emad Yehia]

Yes all wiring is connected well and I disassembled the rear right sensor and turned on engine and test the sensor it work because it be magnetic and turned off engine the sensor is off magnetic it mean it connected well