French Car Forum

matt · Post by **matt** » 10 Mar 2005, 19:28

HELP!! Abs warning lamp stays on when driving,the big problem being my mot tester has just noticed it!Could it be a relay or control unit or a dodgy sensor?Cheers matt[:(]

fastandfurryous · Post by **fastandfurryous** » 10 Mar 2005, 21:21

Does the lamp go off, and then come back on again after moving off, or does it never go out? It *could* be any one of the probelms you've listed, although the favourite is a dead wheel sensor. This could either be a dead sensor, or broken wires to it. The location of the wires does lend itself to corrosion, and hence the ECU thinks it sees a dead wheel sensor, when in fact it's broken wires.
If you jam on the brakes with the warning lamp on, do you get any ABS effect, or is it locked wheels all the way?

matt · Post by **matt** » 10 Mar 2005, 21:41

The lamp flashes as you start the engine(like its checking system)but then just stays on,even if you dont drive off.The wheels do lock up when the light is on,so it looks like checking all the sensors and replacing if necessary.

martyb2 · Post by **martyb2** » 10 Mar 2005, 22:40

check the abs rings on the driveshafts, it could be that one or both of them has split, I had the same problems on a mondeo and a cavalier, and changed the cv joint and it sorted the prob, although chances are you'll have to change the full shaft if this is the case

PowerLee · Post by **PowerLee** » 10 Mar 2005, 22:55

Hi
What car is this on? Keep it quite but some Bosch ABS systems fitted to the June 1995 onwards 405s & the 306 CAN flash fault codes out on the dash, All you need for this high tech diagnositc work is a bit of wire!

matt · Post by **matt** » 10 Mar 2005, 23:22

Its a 93 405 with bendix additional abs(the abs unit is down in the inner wing).

matt · Post by **matt** » 10 Mar 2005, 23:50

[quote]Originally posted by matt

Its a 93 405 with bendix additional abs(the abs unit is down in the inner wing).With regards to the rings on the hubs i noticed some old damage to one of them,probably caused by contact with handbrake arm.But would this still throw a fault up even if im not moving?The damage was done well before this abs fault appeared.

tonespeed1999 · Post by **tonespeed1999** » 10 Mar 2005, 23:51

i made a flash code reader for a 405 a couple of years ago,made from some wire,a bulb and a flick switch,worked as the instructions said on the website,but i think it would only do engine codes.if i find the plans ill post it on here!

PowerLee · Post by **PowerLee** » 11 Mar 2005, 00:01

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by tonespeed1999

i made a flash code reader for a 405 a couple of years ago,made from some wire,a bulb and a flick switch,worked as the instructions said on the website,but i think it would only do engine codes.if i find the plans ill post it on here!
<hr height="1" noshade id="quote"></blockquote id="quote">
Hi the ABS flash codes using a bit of wire only work on the Bosch 2E ABS system as fitted to the June 1995 onwards 405s & most 306s

fastandfurryous · Post by **fastandfurryous** » 11 Mar 2005, 16:51

My 94 405 had bendix additional ABS too, and can throw up the odd warning lamp every now and then. In most cases if you reset the system, it dissapears. What's relevent to you though, is that when I have a warning lamp up, it still manages to ABS properly. As I understand it, if you loose a wheel sensor on this system, it then ignores that sensor, and modulates that wheel brake with the other wheel on that axle, whilst throwing up an ABS warning lamp.
This would indicate that you have either more than one dead wheel sensor, or a more complex fault. It is possible to remove the multi-plug from the ABS unit (with the ignition OFF.. preferably with the battery d/c too) and use a multimeter to check the wiring too the wheel sensor. I'm sure I've read somewhere that if you have an osciliscope, or a decent multimeter which can measure frequency, you can jack up the wheel concerned, rotate it, and see the output on your meter/scope.
I have in the past (on a 306 with an abs fault) managed to get a peugeot dealer to attatch their equipement to the car and read the fault for free. I claimed I would need to speak to the car's owner as to when I could book it in for the work, and never actually did. Turned out to be a dead sensor. If yours is a number of dead sensors, the front ones are relatively easy to get out, wheras the rears (esp. if you have drums) are a complete pain.

matt · Post by **matt** » 11 Mar 2005, 21:15

SORTED!!! This morning i cleaned up all the sensors and gears,cleaned up a corroded fuse in engine bay,wobbled a few connections on the abs unit and bingo,light went out after engine is started.The rear sensors were a pig to remove and very dirty.But it still occasionally throws a fault and behaved long enough to go through re-test.Thanks to all for advice!