Replacing rear brake pads causes EPB fault

[Old Navman]

Last week I had to change my rear brake pads. The rear calipers are fitted with electric parking brakes so I used VCDS. After changing both rear brake pads now only the left EPB works. Dashboard showing flashing P, exclamation mark, EPB button light and very loud audio alarm when mobile. Checked the electric motor on the problem site (RHS) by applying direct current - Ok, checked EPB button by swapping with new spare Ok. Deleted all DTC fault codes, tried reset 30, disconnecting battery for 30 min nothing works. When re-scanned VCDS shows:

00473 - Control Module for Elec Park brake (J540)
013 check DTC memory - intermittent
fault status 00101101, fault priority 0
fault frequency 255.

I've read somewhere that those electric motors are separately controlled by a module located in the boot (battery side?) Still, is it possible for one to be working Ok and the other to be faulty? If that is so, I'm thinking there must be a control switch for each individual EPB?

Any suggestions guys?

[Old Navman]

Does anybody have an electrical schematic diagram for the rear EPB's?

[h100vw]

I can probably find one but what I'd do is go back in with your VCDS and Start lining replacement again and then End lining replacement straight away.

Maybe the piston wasnt wound back far enough or something.

Gavin

[Old Navman]

Thanks, I'd appreciate it.

I've tried using that option in VCDS but it only worked on one side (LHS). I was kinda hoping that it would be simply a matter of a faulty actuator motor but with motor operating when powered directly by 12V it looks like it has to be something else. I've eliminated the EPB switch so now apart from a broken wire (both parking brakes were working Ok prior to disassembly) I can only think of one more thing that is the EPB control module. The calipers were disassembled, cleaned and a seal repair kit used. The piston was hand pressure fitted so it's not likely to be stuck but in any event there is no current coming to the RHS actuator motor connector plug so this is where the problem lies.

[Lucas_R]

Perhaps you have managed to damage the wiring/plug running to the RHS parking brake motor when removing the calipers? If there is a plug at the caliper make sure there is no debris on the connections and that it is plugged in correctly.

[Old Navman]

Yes, the plug not having been taken off for many years was really stuck and it took some persuasion & WD40 to get it off. It's only 2 wire plug and while I did measure the continuity (current status grounded/closed circuit) to a closer physical inspection the plug appeared OK. I've used electrical contact cleaner a fair bit to clean it out so unless the pins were somehow pulled out and are touching ... If possible, I don't want to go the full Monty pulling off the center console to get to the EPB control module if I can avoid it

[Old Navman]

Today I got the faulty? EPB control module out - it's the 3C0 907 801B C2.1. Can this module be replaced by a more updated version say A? Does it then require security code for new adaptation?

[Lucas_R]

A newer version will have a different alphabetical reference at the end of the part number (eg B,C,D etc) as well as a newer build date. See this one for example:

Volkswagen Passat B6 Electric Handbrake Control Module Unit 3C0 907 801 J OEM 4058659693674 | eBay

Best to try and find the same part number so you know you can swap a like for like product, but failing that a newer part number should theoretically work also.

[Old Navman]

A newer version will have a different alphabetical reference at the end of the part number (eg B,C,D etc) as well as a newer build date. See this one for example:

Volkswagen Passat B6 Electric Handbrake Control Module Unit 3C0 907 801 J OEM 4058659693674 | eBay

Best to try and find the same part number so you know you can swap a like for like product, but failing that a newer part number should theoretically work also.

I'll try to get a replacement with same ref.

[kamold]

You can use the newer 3AA part, it's a supersession from the 3C0 part. Anything up to 3AA907801J.

[Old Navman]

You can use the newer 3AA part, it's a supersession from the 3C0 part. Anything up to 3AA907801J.

Cheers kamold, I'm hoping to p/u used one (happens to be same revision) tomorrow as I surely don't want to spend $1350 plus GST for a new one from VW.

[kamold]

The 3C0 parts are prone to failure. The superceding 3AA part is what I'd go for.

[Old Navman]

The 3C0 parts are prone to failure. The superceding 3AA part is what I'd go for.

I see, just a pity that there isn't one of those newer ones around ATM. Buying this (old one) is hand since it's "local pickup" so I can get my hands on it straight away. Otherwise I gotta wait for the item to be posted (maybe from o/s?). After driving with this constant loud ding dong alarm bell I reckon I need to get my ears checked out. I've only driven the car like that a couple of times but still. I was a bit concerned that this fault might also affect things like the ABS or the stability control but there was no light indication on the dashboard those weren't working.

[Old Navman]

So, I p/u the module today, it's the same part number but the revision is different - still it should work. Unfortunately, so far I only succeeded in creating more faults than before. Firstly, I've gone from 1 EPB control module fault to 5 because now both left & right motors are causing faults.

Also ABS, stability control, EPC, etc. etc. There are so many guides out there on "how to" that I'm not really clear which one should be followed. The rear EPB motors have come up (I think) because they're not coded to the ABS module? For whatever reason the VCDS will not allow me to code the control module to 0000012 - parking brake with auto-hold. It comes back with this error message: coding rejected, error 22 condition not correct or request sequence error. Does this operation required security pin? One is mentioned somewhere in Ross-Tech guide but I'll be damned if I can find it now.

The only good thing that happened is the ding dong alarm has stopped however only the left motor operated from time to time but not both. I've driven the vehicle around the block and let it stand & tried to clear the codes - no good. Not sure whether now I should try disconnecting the battery for 10min, trying to clear the codes and see if that works?

[Old Navman]

Here is the screen shot of the dashboard ATM - even the tire pressure fault has now appeared.