TRACS/ABS: Warning lights on

[CARPMAN]

Over the past few weeks my TRACS/ABS warning lights have been coming on . When I first start up in the morning they come on until I go out of my driveway and turn sharp left then they go out. However this only lasts for a short while then they come on again.

Reading some of the threads on the forum it was suggested that to try wiggling the key in the ignition whilst the engine is running. this I did this morning and low and behold the lights went out and so far have stayed out.

Can anybody enlighten me as to what the problem is and if it is serious or just a loose connection. Will the lights now stay out? Does it mean that the ABS system is working OK or not.

Many Thanks

[Chris_Rogers]

http://www.volvoforums.org.uk/showthread.php?t=54629

[CARPMAN]

Thanks Chris for the info. The solution looks fairly straightforward will give it a go.

[CARPMAN]

I have today replaced the electrical portion of the ignition switch on my 1997
20 valve V70 automatic following the proceedure shown on the link listed.

However allthough the ignition switch seems more positive the ABS/TRACS warning light still comes on sometimes when I first start up. It however usually goes out almost straightaway when I turn the first sharp left hand corner. Its then stays out for a while sometimes for miles and sometimes only a short distance.

I did notice today that It came on after about 5 miles when I braked and felt a very slight shudder through the brake pedal. This didnt happen again allthough the light stayed on until I turned the car off.

The only thing that might have some bearing on this is the fact That prior to the ABS/TRACS warning light first appearing I changed both wishbone assemblies and had to hammer out the ball joint pinch bolt on the off side as it was ceased.

Has anyone any suggestions as to what to do next to cure this.

Thank you

[kevinbis]

I had trouble with solder joints in ECU and sorted it out as explained in this link.

http://www.volvoforums.org.uk/showthread.php?t=7414

[big radius]

i had similar trouble so what i did was with the ingition on i put a multi meter across both terminals of each abs sensor and tested by jacking up the wheel to be tested and rotating the wheel.
what you should see is the voltage flick from 9v to 10v if the voltage does not change you have a faulty sensor.

one of my rear sensors stuck at 10v and a pair of rear sensors later (as they come as a pair on the rear) all is well hope this helps

kev

[CARPMAN]

Many thanks for the suggestions. If it turns out to be the ABS control Unit is this situated under the ABS Modulator if so is it easy to remove and do you as it says in the Haynes Manual have to drain the whole Hydraulic brake fluid system and them remove it complete with the modulator.

[Chris_Rogers]

No follow the info here:

http://home.earthlink.net/~vicrocha/

and here:

http://www.volvoforums.org.uk/showthread.php?t=72655

[vilda hilda]

Hi guys, thank you for the very detailed "how to fix ABS and TRACS" lights. I followed the instructions and resoldered the ABS control box and yes it works fine now and got a clean MOT sheet as a result.