Abs Light When Starting In The Morning

[benzino]

Can Somebody Give Me Some Advice On The Following:

Recently, When Starting The Car In The Morning, The Abs/esp Malfunction Warning Comes Up And The Light Stays On While Engine Running. If I Switch Off And Start Again, It Goes Away (no Malfunctions Or Light). Then For The Rest Of The Day Nothing Comes Up On Starting. Ocassionally (once Or Twice A Week) The Same Malfunction/light Comes Up While Driving. Again, If I Pull Over And Restart, It Goes Away??? Can Somebody Let Me Know Why This May Be

 

[Carlo]

Could be your'e brakelight switch.
The switch is located on the brake pedal.

Carlo

 

[Ian B Walker]

Two things come to mind apart from the brake switch.

1) Failing battery, enough power to start the car etc but not enough to run the electrics after starting. ( Happened on my 124 estate.)

2) OVP relay failing.

 

[Carlo]

Good thinking Ian .
Indeed , in your'e case with an E320 it could be the black relay with the fuses on in the black module box ( under the bonnet right side close to the windscreen )

Carlo

 

[KLP 92]

Next time in the morning start the car without putting your foot on the brake. If the light still comes on then its probably not you brake light switch, I would agree with Ian B Walker's suggestions.

 

[robert.saunders]

I had an annoying ABS light on an old Ford Sierra 4x4 I used to have - it stayed on whilst driving, from start-up. Anyway, I didn't have a manual so assumed some sort of ABS fault or fuse/relay issue, and ignored it. It always stopped when braking.

About a week later I had a catastrophic brake failure and wrote the car off (good thing in some people's eyes), so not worth ignoring I suppose.

Not that this could be the same issue, but lights I guess illuminate for a reason! I tend not to ignore them now hahaha

Rob

 

[benzino]

thanks

thank you everyone for your suggestions and information

personally i dont think it is failing battery as all electrics are fine and start up is fine

since i wrote with this question the morning warning signs are less frequent, infact just came up yesterday after 3 or 4 days.

i have been pressing the brake pedal before starting though. may be thats why. any ideas why doing this would stop the warning lights???

 

[benzino]

ovp relay

btw what is this ovp relay and what does it do? if it is failing, does it effect the braking system itself? or is it just effecting the warning system?

what needs to be done to correct it?

 

[snanceki]

OVP = Over voltage Protection (relay).
It was/is used to safeguard sensitive electronic circuits eg ABS, ASR from overvoltage spikes during jump start etc. on some modelsd. you do not refer to vehicle type.
Known to give problems due to faulty circuit board manufacture.
Normal mode is ON/OFF but due to poor soldered joints etc it can cause low voltage which the system picks up and flags as a problem once unit gets warm/subject to vibration etc.
Brake light switch (two circuits one for the brake lights/gear selector, one for ABS etc in same switch NormallyClosed/NOpen) is most common cause.
Unlikely battery.
The fact that the problem is not present at start up (or on reset) confirms that self test is OK. Therefore must be something which is not checked at startup or is a a transient.
Other possibility is wheel speed sensor. Is your ASR OK? If OK not speed sensor.
Good luck,
Stuart

 

[jaymanek]

Ive had this around 5 times on cars ive sold and its always been the switch at the brake pedal...