Haldex fault code 00526

[Blackcupraa]

Hi guys,

Just scanned the AWD on VCDS lite and came up with 00526 - Brake Light Switch (F): Implausible Signal. Looking at the possible symptoms it doesn't sound like it should and yes, I have Brake lights when pedal depressed.

Would this prevent the Haldex from working on my 1999 Audi S3?

I've driven the car and when I tried to come up the driveway on a small patch of ice (the rear wheels were on snow) and it sounded as though the front passenger side diff was grinding (maybe transfer box). The car refused to go up the drive unless I rolled back and then got traction on the fronts to get me over it.. SHould the rear wheels have "activated to help me up?

Note the driveway is not steep by any stretch of the imagination, it's as steep as a stepped curb, roughly 5 degrees I would imagine for about 2-3 feet then level.

 

[Essflee]

My car keeps throwing this fault too, from reading up on various posts people are saying that a faulty break light switch will knock the haldex off, the break lights still work but the car thinks its breaking so only runs fwd.

Mine is intermittent which hasn't caused to much off a problem, if your struggling to get up your drive which isn't steep then I'd change the switch over.

You should pull up pretty much any hill with snow if the 4wd is working correctly. With all this snow I've actually been looking for hills and roads with lots of snow, lol

 

[Blackcupraa]

Where's the switch located?

Edit: Always Google before posting, engage brain before typing!!!!!

 

[s3dave]

There is an updated brake light switch that stops the intermittent fault...

 

[Blackcupraa]

Just read upteen posts on VWVortex, SCN, ASN etc and seems to be conflicting information.

In order to fit this, does the Brake pedal have to be fully depressed or not?

 

[Gizmo20VT]

I need to find this info, But AFAIK you have to press the brake pedal before logging in to the Haldex on VCDS.

Edit: From Ross tech is says Auto gearbox's however if I do press the pedal before logging in I do not receive the error

00526 - Ross-Tech Wiki

 

[Blackcupraa]

Just read upteen posts on VWVortex, SCN, ASN etc and seems to be conflicting information.

In order to fit this, does the Brake pedal have to be fully depressed or not?

Anybody got any ideas?

 

[<tuffty/>]

Implausible signal is a code normally meaning the controller doesn't understand the 'data' its receiving from it...

As for your code....
00526 - Ross-Tech Wiki

00526 - Brake Light Switch (F): Circuit Malfunction
Possible Symptoms

MIL (Malfunction Indicator Light)
No Brake Lights

Possible Causes

Wiring and/or connections faulty between Brake Switch, Brake Lights and/or ABS Controle Module
Brake Light Switch (F) damaged
Brake Light faulty
Fuse(s) faulty

Possible Solutions

Check wiring and connections
Replace Brake Light Switch (F)
Check / Replace fuses(s)
Check / Replace Brake Lights
Check Brake Light Switch (F) in ABS Measuring Block

Special Notes

FAQ 2.7. Many Automatic Transmission Control Modules will show a DTC 00526 or 17087 that indicates a faulty brake light switch. This can be ignored and will not appear if you press the brakes once before checking for Fault Codes.


00526 - Brake Light Switch (F): Implausible Signal
Possible Causes

Wiring/Connectors from/to Brake Light Switch (F) faulty
Brake Light Switch (F) faulty

Possible Solutions

Check/Repair Wiring/Connectors from/to Brake Light Switch (F)
Check/Replace Brake Light Switch (F)
Check Measuring Value Blocks (MVB)

Special Notes

FAQ 2.7. Many Automatic Transmission Control Modules will show a DTC 00526 or 17087 that indicates a faulty brake light switch. This can be ignored and will not appear if you press the brakes once before checking for Fault Codes.

...have changed loads of brake switches as they seem to fail fairly regularly... might be worth changing it or at the least check the Haldex plug by the diff as these are known to corrode

<tuffty/>

 

[s3dave]

Anybody got any ideas?

The new type switch has no ratchet feature and just turns and locks in place.. 5 mins and done..

 

[Blackcupraa]

Thanks guys, switch is here just need to fit it.

I haven't checked the plug but had no issues when it was serviced recently. I'll jack it up and check over the weekend, snow dependant of course.