ABS TRACS lights coming on intermittently

[El Padrino]

Any suggestions to clean excess flux off the PCB after soldering please? A video suggests using Isopropyl alcohol to clean off the flux. Will WD-40, GT85 do the same?

Many thanks in advance.

[El Padrino]

ABS module has been resoldered and was bolted back on this morning. Not done a test drive yet. Before I do the test drive, shall I clear any DTC errors codes stored in the ECU, start the engine and see what happens on the test drive?

Anything I've missed?

[ITSv40]

Originally Posted by El Padrino

ABS module has been resoldered and was bolted back on this morning. Not done a test drive yet. Before I do the test drive, shall I clear any DTC errors codes stored in the ECU, start the engine and see what happens on the test drive?

Anything I've missed?

Yes, clear the codes. At least you will have a known starting point if any codes return. Good luck.

[El Padrino]

Originally Posted by ITSv40

Yes, clear the codes. At least you will have a known starting point if any codes return. Good luck.

Thanks ITSv40, thought that'd be the case.

[El Padrino]

Before setting off on a test drive, I cleared the DTC codes via the 850 OBII app, did another scan and had the following output:

COMBI has 1 DTC: 02

CI-221: Vehicle speed signal missing [bad ABS module solders?]
[+ click to view more]

ABS has 4 DTC: 10 11 20 64

ABS-141: Brake Pedal Sensor, short [or bad ABS module solders, wiring, brake pedal sensor, or ignition switch]

ABS-311: Left Front Wheel Sensor, open/short? [or bad ABS module solders or ignition switch]

ABS-312: Right Front Wheel Sensor, open/short? [or bad ABS module solders or ignition switch]

ABS-321: Left Front Wheel Sensor, irregular > 25 mph (ie, interference or excess oscillation > 40 km/h) [or bad ABS module solders or ignition switch]
[+ click to view more]

At this point I wondered if my soldering had made things worse and when I accidently knocked the module off the bench I was soldering at , as I only ever had the top DTC error relating to the module.

During the drive of about an hour with speeds up to 70mph, the ABS/TRACS lights stayed on permently. The speedo was working fine at all times. At one point I stopped for petrol and hoped the lights would go out after turning off the engine. They didn't turn off. I continued driving for a while, then stopped to clear the DTC codes and do another scan. The second scan gave me the following output and only two errors this time:

ABS has 2 DTC: 20 30

ABS-312: Right Front Wheel Sensor, open/short? [or bad ABS module solders or ignition switch]

ABS-313: Left Rear Wheel Sensor, open/short? [or bad ABS module solders or ignition switch]

The right front ABS sensor is new, so wonder if my resoldering on the pins are not good enough. The left rear wheel sensor hasn't been replaced or is my resoldering on the pins for it not good enough again.

So, I'm thinking re-open the ABS module again and apply more solder to the specific pins bringing up the errors or just keep trying to clear the DTC codes. The 850 OBDII app is not the easiest to use and I'm not sure if I'm using it correctly. How can two scans give two separate results? On one scan, I can't remember in which sub-menu it was, but there were two ABS options to check, so I ticked both and did a scan (after I had done another clear DTC first). That scan said I had no DTC errors, but I still had the ABS/TRACS lights on. I then did a full scan by ticking all the available options, that's when I had the second lot of results above, with just the two errors. So the dreaded lights still haunt me

[El Padrino]

Between limited time yesterday, I cleared the DTC codes again and did a scan twice with the 850 OBDII app. And as expected, I had another set of different results to my previous scans. This time, the following same error came up twice, so there's some consistency at least.

ABS-312: Right Front Wheel Sensor, open/short? [or bad ABS module solders or ignition switch]

I didn't troubleshoot any of the issues relating to the other DTC codes I got on Saturday (as in the above post), so I was expecting them still to appear after another scan. Regarding the 850 ODBII app, would you folks say it's accurate and is telling me the correct output? I'm a bit dubious now as I've had different outputs from each scan.

Luxobarge ...... are you there?

[Luxobarge]

Hiya,

Firstly, yes, the app is accurate so don't start doubting that.

Given the variety of codes, my first reaction is that it's still bad solder joints on those pins. I hate to cast doubt on your soldering skills but I'm struggling to believe that all those sensors or wiring are faulty, and I can't see what else it could be. This happened to me, the fist time I "soldered" it I failed to remove the clear jel coat covering the PCB, so my efforts at soldering had no effect. I still can't understand how I managed that, but the second time I had it apart I did it properly and never had a code since.

If you have another go, I can strongly recommend doing it under a large illuminated magnifying glass as I did - I borrowed the one my wife uses for sewing but if you don't have one try and beg or borrow one somehow. Using this, cracks in the solder that were invisible to the naked eye were clear to see, as was the end result after re-soldering. It also helps you to see if you've bridged any pins with solder which might be the case here. I'd not recommend using additional flux, it's not necessary and makes a right mess on the PCB, which might be hiding any solder that's got where it shouldn't.

HTH....

[El Padrino]

Originally Posted by Luxobarge

Hiya,

Firstly, yes, the app is accurate so don't start doubting that.

Given the variety of codes, my first reaction is that it's still bad solder joints on those pins. I hate to cast doubt on your soldering skills but I'm struggling to believe that all those sensors or wiring are faulty, and I can't see what else it could be. This happened to me, the fist time I "soldered" it I failed to remove the clear jel coat covering the PCB, so my efforts at soldering had no effect. I still can't understand how I managed that, but the second time I had it apart I did it properly and never had a code since.

If you have another go, I can strongly recommend doing it under a large illuminated magnifying glass as I did - I borrowed the one my wife uses for sewing but if you don't have one try and beg or borrow one somehow. Using this, cracks in the solder that were invisible to the naked eye were clear to see, as was the end result after re-soldering. It also helps you to see if you've bridged any pins with solder which might be the case here. I'd not recommend using additional flux, it's not necessary and makes a right mess on the PCB, which might be hiding any solder that's got where it shouldn't.

HTH....

Thanks Luxobarge I'll be removing the ABS module again to resolder the PINS that are relating to the DTC faults. Soldering is not something I've always done, so that could be the issue. I did make sure that any pins that weren't supposed to be bridged were not. I do have an illuminated magnifying glass. I'll get in there again with the soldering iron. The clear membrane on my module had been cut away before by whoever rebuilt it last. I'm determined to get rid of the lights and will keep going until I do.

[Bob Meadows]

When reinstating the module & the electrical connections double check that the plug is seated correctly and that the metal securing fixing on top of the plug is pushed fully over securing this plug.
(Worth doing a wiring check & clean whilst doing the above)

When I first purchased my car this fitting had not been fully engaged although it worked OK.
Good Luck.
Bob.

[El Padrino]

Originally Posted by Bob Meadows

When reinstating the module & the electrical connections double check that the plug is seated correctly and that the metal securing fixing on top of the plug is pushed fully over securing this plug.
(Worth doing a wiring check & clean whilst doing the above)

When I first purchased my car this fitting had not been fully engaged although it worked OK.
Good Luck.
Bob.

Hi Mr Meadows thanks for your reply. Which 'metal securing fixing' are you referring to? I don't even have the plastic cover on my plug connector, just secured with a zip tie (see the photo). I'm sure the wiring plug was seated properly by pressing down on it as far as it would go.

The wiring check - do you mean probe each connector on the wiring plug with a multimeter or just a visual check for frays etc? And lastly, is it OK to spray contact cleaner into the wiring plug (with the multi-coloured leads going into it) and the ABS pump power plug?