For about a week now my remote central locking has stopped working and I'm stumped as to why. Can anyone help?

It does work intermittently, but increasingly it does not work at all. The locks themselves work when I use the key in the door, but not when I try and do it remotely.

I have had water ingress issue before and repaired a few damaged nodes in the footwell and since then there have been no issues.

I've checked under the carpet and everything is dry and as it should be.

So I decided to take a look inside the CCM, which showed evidence of minor corrosion to some of the connecting pins, probably from the water leak earlier this year. There's no sign of water damage to the CCM at all.

Now here's what I've tried:

1. Tried both key fobs with new batteries. Doesn't fix the problem so I know it's not a battery or fob issue.

2. I soldered on replacement connections on the CCM for pins 9, 11, and 13 on the 15-pin plug going into the CCM as these were the most damaged connections. According to this site:

https://sites.google.com/site/1810martin/b5-ccm-wiring

these are the connections for the interior sensors, alarm horn, and the alarm fuse.

The connections for the central locking aerial are pins 7 and 10, which show no sign of any damage at all. So yesterday I plugged the CCM back in with the repaired connections and my central locking worked fine again. It worked fine this morning, but then this evening it's completely unresponsive again. I'm completely stumped as to why the central locking won't work.

The two aerial wires leading from the CCM look fine as far as I can trace them (from CCM up to passenger door pillar) so no obvious central locking aerial damage.

I'm not an electrical expert but I can't figure out why the remote locking would go from working, to intermittent, to failure and then briefly back to working again having eliminated a fob/battery issue.

Are there any fuses or other wires I ought to be checking? Could it be something other than a dodgy aerial connection? I'm stumped.

Intermittent ground to the CCM? I think the CCM ground is on a big stud close to the CCM housing.

Can you get the car scanned with VCDS?

Intermittent ground to the CCM? I think the CCM ground is on a big stud close to the CCM housing.

Can you get the car scanned with VCDS?

Hadn't thought about checking the earth, will have a look tomorrow.

As luck would have it my laptop with VAGCOM on broke last week so no chance of scanning it for a few days at least.

Managed to check the earth this morning. It's bone dry with no corrosion so no issues there.

One thing I have noticed is that when I manually unlock the car at the driver's door, the small red LED on the door lock continues to flash and if I sit in the car a few seconds without starting the engine, the alarm goes off. The alarm clearly isn't disarmed for whatever reason as it should be and the central locking still doesn't work 90% of the time.

I've tried it about 20 times this morning, the central locking worked once and disarmed the alarm but the rest of the time it didn't.

It's now pouring with rain so not going out to do more work on the car but I'm stumped. I haven't checked fuses S111 and S144 on the relay panel but I'd have thought if the fuses had gone the central locking wouldn't work 100% of the time, rather than just intermittent.

Have also noticed the right rear interior light isn't working, but the node and wires are all still intact and joined together.

Will have to try and get VAGCOM readout but I'm stumped and probably missing something obvious.

VAGCOM readout as follows:

VAG-COM Version: Release 409.1-S

Chassis Type: 3U - Skoda Superb

Scan: 01,02,03,08,15,16,17,19,35,36,37,46,55,56,58

-------------------------------------------------------------------------------

Address 01: Engine

Controller: 4B0 906 018 DC

Component: 1.8L R4/5VT G 0001

Coding: 11001

Shop #: WSC 00028

TMBCL23U729007508 SKZ7Z0A1168119

3 Faults Found:

16795 - Secondary Air Injection System: Incorrect Flow Detected

P0411 - 35-10 - - - Intermittent

16891 - Idle Control System RPM Higher than Expected.

P0507 - 35-10 - - - Intermittent

18010 - Power Supply Terminal 30: Voltage too Low

P1602 - 35-10 - - - Intermittent

Readiness: 0000 0000

-------------------------------------------------------------------------------

Address 03: ABS Brakes

Controller: 8E0 614 111 B

Component: ABS/EDS 5.3 FRONT D10

Coding: 0273004283

Shop #: BB 24332

No fault code found.

-------------------------------------------------------------------------------

Address 08: Auto HVAC

Controller: 3U0 907 044 A

Component: CLIMATRONIC S B5 C 2004

Coding: 17000

Shop #: WSC 00028

1 Fault Found:

01341 - Control Module in Instrument Panel On Comfort CAN (J285)

27-10 - Implausible Signal - Intermittent

-------------------------------------------------------------------------------

Skipping Address 15-Airbags

-------------------------------------------------------------------------------

Address 16: Steering wheel

Controller: 1J0 907 487 A

Component: Lenkradelektronik 0004

Coding: 00118

Shop #: WSC 00028

No fault code found.

-------------------------------------------------------------------------------

Address 17: Instruments

Controller: 3U0 920 940 C

Component: KOMBI+WEGFAHRSP VDO V04

Coding: 31415

Shop #: WSC 00000

TMBCL23U729007508 SKZ7Z0A1168119

4 Faults Found:

00562 - Sensor for Oil Level/Temperature (G266)

30-10 - Open or Short to B+ - Intermittent

01336 - Data Bus for Comfort System

49-10 - No Communications - Intermittent

01336 - Data Bus for Comfort System

80-10 - Single-Wire Operation - Intermittent

01330 - Central Control Module for Central Convenience (J393)

49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------

Address 19: CAN Gateway

Controller: 6N0 909 901

Component: Gateway K<->CAN 0001

Coding: 00004

Shop #: WSC 00028

3 Faults Found:

01336 - Data Bus for Comfort System

49-10 - No Communications - Intermittent

01336 - Data Bus for Comfort System

80-10 - Single-Wire Operation - Intermittent

01330 - Central Control Module for Central Convenience (J393)

49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------

Address 46: Central Conv.

Controller: 1C0 959 799 B

Component: 5F Komfortgerát HLO 0003

Coding: 00258

Shop #: WSC 00028

3 Faults Found:

01336 - Data Bus for Comfort System

80-00 - Single-Wire Operation

01134 - Alarm Horn (H12)

49-10 - No Communications - Intermittent

01135 - Interior Monitoring Sensors

36-10 - Open Circuit - Intermittent

-------------------------------------------------------------------------------

Address 56: Radio

Controller: 1U0 035 161 D

Component: Radio GRO 0001

Coding: 00407

Shop #: WSC 00028

1 Fault Found:

01336 - Data Bus for Comfort System

80-10 - Single-Wire Operation - Intermittent

End --------------------------------------------------------------------------------------------------

So it mainly seems to be error code 1336, relating to a lack of signal from the CCM. There were a couple of corroded plugs on the CCM which I cleaned up (interior lights came back on, except the right rear, and puddle lights came back). I cleared the fault codes and re-scanned and now no codes are showing at all. The central locking and alarm problem still continues though.

I'm afraid that once one of these cars gets wet, the connectors and various node joints in the harness are a continuous and virtually unfixable source of trouble. There are so many dissimilar metals within the electrical system that severe and continuing electrolytic corrosion is inevitable. Brilliant VAG design work.

Moral: Fix plenum drains and pollen filter housing outer seal before any water gets in.

rotodiesel.

I'm afraid that once one of these cars gets wet, the connectors and various node joints in the harness are a continuous and virtually unfixable source of trouble. There are so many dissimilar metals within the electrical system that severe and continuing electrolytic corrosion is inevitable. Brilliant VAG design work.

Moral: Fix plenum drains and pollen filter housing outer seal before any water gets in.

rotodiesel.

Sadly you're right, although I did the plenum chamber/pollen filter about a month after I first bought it in Feb 2011. The corrosion now seems to have been caused by residual moisture but it's causing no end of hassle.

I've had a long term loyalty to VAG but as much as I like my Superb (for all the niggles it has) I'll never buy a VAG again. Japanese next time.

So it mainly seems to be error code 1336, relating to a lack of signal from the CCM. There were a couple of corroded plugs on the CCM which I cleaned up (interior lights came back on, except the right rear, and puddle lights came back). I cleared the fault codes and re-scanned and now no codes are showing at all. The central locking and alarm problem still continues though.

Drive it for a while and see which ones come back I guess. Though if you haven't managed to get all the lights back working (and I thought the lights are probably some of the simpler bits) then it is worth re-reviewing the rest of it.

If the CCM connectors were wet I guess that means the CCM was submerged too? Have you thought about checking out the state of the CCM internally? If it is pretty grotty you might try to replace that? I don't know what the implications are re: coding though. >EDIT< it looks like you might have already done this, if so ignore me!

I guess that is was I'd try - though I'm nothing more than an interested amateur where car electrics are concerned!

Good luck!!!

Edited 2 January, 201214 yr by jimbof

Drive it for a while and see which ones come back I guess. Though if you haven't managed to get all the lights back working (and I thought the lights are probably some of the simpler bits) then it is worth re-reviewing the rest of it.

If the CCM connectors were wet I guess that means the CCM was submerged too? Have you thought about checking out the state of the CCM internally? If it is pretty grotty you might try to replace that? I don't know what the implications are re: coding though. >EDIT< it looks like you might have already done this, if so ignore me!

I guess that is was I'd try - though I'm nothing more than an interested amateur where car electrics are concerned!

Good luck!!!

Have had another look today while the rain held off. Three of the wires going into the CCM plugs have mostly corroded away inside the plug itself, and they're all the ones for the central locking/alarm function. Have order some new pins to crimp on so when they arrive that should hopefully restore a clean connection into the CCM.

Have had another look today while the rain held off. Three of the wires going into the CCM plugs have mostly corroded away inside the plug itself, and they're all the ones for the central locking/alarm function. Have order some new pins to crimp on so when they arrive that should hopefully restore a clean connection into the CCM.

Cool, got my fingers crossed for you