How the abs works...

[Skred]

Has anyone replaced the abs control module and knows where it is?


I have the usual ABS/handbrake light on and I've scanned it with vagcom but is kicking up no faults. So i bought a multimeter the other day and I checked the resistance of the two rear abs sensors via the connections underneath the back seats.

Resistance for both was around the 1.2ohms mark which is fine but I noticed that after reconnecting and turning on the ignition that there was no voltage travelling through to the rear sensors. So I've followed the sensor cables back under the nearside sill trim and disappears into the engine bay via the passenger footwell. From here I'm having difficulty

Am I right in thinking these sensor cables are connected to an abs module that monitors the four wheels? If this is so where abouts is it in the engine bay? Because vagcom isn't reading the fault its my understanding that the unit supplying the power must be faulty.

[VR6_Wherry]

What year is your car as i'm sure the modules differ?

Mine is found at the back right of the engine bay behind the coolant expansion tank, i think.

[Skred]

its a 1995 gti 16v. ill have a look behind the expansion tank.
what causes the module 2 fail? solders?
 it is strange how vagcom doesnt register any faults tho

[VR6_Wherry]

have you tested the ABS by slamming your foot down on the pedal? lol

[Skred]

haha, yup, it doesn't work, she's a locker upper

[javalin]

>Because vagcom isn't reading the fault its my understanding that the unit supplying the power must be faulty.
does VCDS see the control unit?  I.e. if you scan the ABS module does it talk to you?

[Skred]

Hi Javalin,

As far as I can work out, it is scanning the ABS because when selecting the ABS to scan, it begins clicking away behind the dash. That said, no information is pulled through into the Controller info window of VCDS, like
"Vag number", "component", "soft coding" etc

I don't know if information is meant to be transferred over but it certainly is when the engine or airbag is scanned.

Because there is a fault that VCDS isn't picking up, I am led to believe the abs module under the bonnet is knackered. Would you agree?

[javalin]

sounds like it can't talk to the ABS controller.   Doesn't mean its knackered nessessarily - could just be unplugged.  Have you checked Fuses, etc?  I'd find the unit and check its connections, and re-scan first....

J

[Skred]

Ok, will check it all over.

Can I double check that this is the abs module under the bonnet that Vr6 wherry described?

[javalin]

should be.  on mine (AGG engine) I think it is below and slightly behind the coolant expansion tank and has 4 thin brake pipes coming out of it.