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Matt
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21990
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a peugeot 307cc convertible it was in a collision now

Customer Question

so far I have  taken off the speed sensor and clean the area where they sit with wd40 nd replace them.

Submitted: 3 years ago.
Category: Car
Expert:  Matt replied 3 years ago.
Hello

If the ABS light is staying on then this would indicate a fault with the system which shouldn't effect the regular braking performance so the car is still safe to drive.

The quickest route to repair is to have the car plugged into a diagnostic machine which will read off the fault code stored in the ECU (providing the light is still on at this point) and indicate which sensor has failed or whether the fault is more serious.

However with ABS systems 99% of the time its a problem with one of the wheel speed sensors and I'd first check the connections at all four corners first for any signs of corrosion or chafed wiring.
The sensor is located in the wheel hub so you'll have to remove each wheel in turn to inspect them all.
Also check that the toothed wheel that the sensor points to is clean and free of any debris.
you can check each sensor's function by plugging the two output wires into an AC voltmeter and spinning the wheel quite quickly, you should get a voltage signal that increases with rev's.

Its possible that the fault is only a bad connection to one of the wheel sensors.
This may be remedied by removing each wheel in turn and unplugging each sensor and cleaning the contacts with a squirt of electrical contact cleaner. Then refitting.
Customer: replied 3 years ago.

The asr/abs lights doesn't stall on constantly it comes on and off, but even when the lights are not showing on dash the car still struggle or shuts off when I comes to a stand still and ready to move off. Will the speed sensors cause this problem?

Expert:  Matt replied 3 years ago.
Hello Kurtis

yes failing ABS sensors can give all sorts of issue as it'll be triggering the traction control and cutting engine power as well as braking the odd wheel and generally making the ride quite unpleasent
Matt and 2 other Car Specialists are ready to help you
Customer: replied 3 years ago.

I thought I had to check out what you have told me so I can know how to rate you

Expert:  Matt replied 3 years ago.
No problem

just get back to me on this post if I can help further
Customer: replied 3 years ago.

Hi I have taken off the speed sensors and clean them as the mechanic is saying that he figure that's the fault now it's saying main brake swith information fault. Not characterized, engine fuse box fault,ECU not communicating on the CAN

Expert:  Matt replied 3 years ago.
Hello Kurtis

this sounds like the ABS controller has lost its power and or the wheel speed sensor signals and its a bit upset

reconnect your sensors
then remove and refit the ABS fuses in the fusebox

if this doesn't help then I'd try resetting the ECU by disconnecting the battery cables and clamping them together for 10 mins. Remove both battery leads from the battery then use a nut and bolt or G-clamp to hold both battery lead terminals together.

This discharges any capacitors / memory within the ECU and around the car so ensures all memory settings are wiped clear - back to the factory default.
Customer: replied 3 years ago.

Thanks for replying ill try that tomorrow and reply to you thanks again

Expert:  Matt replied 3 years ago.
No problem
Customer: replied 3 years ago.

Thanks a lot

Expert:  Matt replied 3 years ago.
Ok Kurtis
Customer: replied 3 years ago.

Hi if I take off the battery will I need a code to set back the radio

Expert:  Matt replied 3 years ago.
Hello Kurtis

yes you will need the radio code if you disconnect the battery

however if you know the radio serial number ( found on a sticker on the back of it) then there's this little free programme to provide the code

http://www.youtube.com/watch?v=AbyatO8aDH0
Customer: replied 3 years ago.

Hi matt I took the car to Peugeot they have taken off they warning lights and I also did a full service.

As I mentioned in our conversation above that the car struggle or shuts off sometime when I slow down or come to a stop.Even now the lights are off the dash. I wondering if you could help with this problem

Expert:  Matt replied 3 years ago.

Hello Kurtis

This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.

As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

Customer: replied 3 years ago.

Ok ill try that thanks again

Expert:  Matt replied 3 years ago.
No problem Kurtis