ABS relays

[Timbo 0]

I have a few queries:

 

1. Behind the glovebox I have three relays; a 79 and two 179s. Searching the forum seems to indicate that most Corrados have only two relays here, those being one each of 79 and 179. This is a 94 VR6 without aircon and with a dealer installed immobiliser/alarm. Why have I got three relays as opposed to two?

 

2. From searching the forum it sounds like 79 is ECU power and 179 is pump power (ignoring my extra 179 for now). Correct?

 

3. I have a permanently on ABS light, which only became permanently on after I fixed the deliberately cut PCB track in the ABS warning light, so a previous owner/garage is obviously trying to hide something :censored:. If I hook up VAGCOM I can't get anything from the ABS ECU, it complains about communication errors. When I switch the ignition on 79 goes on then off a couple of seconds later. 179 doesn't appear to do anything. If I then start the engine I get the same sequence repeated. What sequence/timing should I expect from the relays?

 

The relays seem OK to me, electrically at least. It looks to me like I've got one of two problems; a gubbed ECU or an ECU power problem upstream of relay 79. If anyone has any other ideas I'd like to know though :shrug:.

 

Any advice appreciated, thanks in advance...

[alemay 0]

I'm not sure if this is related but I had a problem with mine where the abs light came on when you turned the car on and wouldn't go off.....unless..... the car had warmed up and you flicked the ignition off then on again. It then flashed slightly and went out. As long as the car was warm the light would go out as it should do. After a few weeks though it wouldn't go off even with this trick.

 

So.....I had the pump hooked up to the VAG machine and it was giving something like defective valve..I can't remember the exact code. The pump was removed and went off to an auto electrician who found that there is a ribbon cable that had broken a couple of tracks. He bypassed the tracks and all was good for about 3 years. Now I have the same problem again. So it's probably just the ribbon cable in the abs unit again!!. No idea if you can get a cable but it's time to go researching again.

 

I hope this helps

 

Andy

 

95 VR6

[Timbo 0]

I don't think that'll be the problem since as far as I can tell the ECU isn't active. Certainly VAGCOM is no help here. In other words I can't actually get to the stage where I'm able to get a pump diagnostic. Thanks for your help though.

 

Another thing that occurs to me is that relay 79 could still be defective despite the fact that it still clicks.

[alemay 0]

Hi Timbo,

 

**** IGNORE BELOW THEY CAN'T HELP *****

 

I've found a place that will sort out the ecu and provide a 2 year guarantee. I'm going to remove mine and send it to them. They take 2-3 days to turn it around and only charge £100 + postage and packing. They say that 99% of them are ecu problems, well probably the ribbon cable, hence the price!

 

Check out http://www.ecutesting.com they are based in Nottingham. V.friendly and seem to know what they are doing.

 

Hope this helps

 

Good luck

 

Andy

[Timbo 0]

Well, having got a cheap ECU (50p off ebay :lol:), it seems like it's not the problem. Having looked at the wiring diagram in Bentley, I'm no longer sure what relay 79 does. It's called "ABS Relay" (helpful :roll:) and seems related to the ABS pressure switch? Furthermore, when 79 clicks on ignition, it sounds like a valve actuates in the ABS pump itself. 179 on the wiring diagram says "ABS Return Flow Pump Relay". Intuitively this seems like it should only be closed when the ABS is actively working?

 

I'll try attacking the whole system with a multimeter and continuity test all the connections, but the general condition of the connectors seems relatively good, so I'm not expecting a problem here. I'm a bit confused why I don't seem to get anything out of VAG-COM, given the engine diagnostics work perfectly. I've got a USB ODB2 cable, are these known to be problematic with ABS diagnostics at all? It's frustrating that the ECU is apparently working but I can't get any diagnostic data from it.

[Toad 0]

I get similar behaviour from my ABS. If it's a cheap usb VAGCOM cable, then it probably is the cable that is at fault. Try getting a serial one to try the ABS with.

[Skimask 0]

Had the same problem with a cheap VAGCOM USB lead- You just have to adjust the timing of the ports on your laptop - it will then show the ABS Controller:

 

 

Although at first VAG-COM couldn't detect the cable - I turned down the COM port settings on the laptop. Go to Hardware - Device manager - Ports (COM&LPT) and Properties of Communication port (USB) usually Com4 and in the advanced settings turn down the 'Latency timer' to 5 - it worked for me.

It depends what COM port you have the connection configured for in VAG-COM, my one only worked on COM4.

[Critical_Mass 10]

Had the same problem with a cheap VAGCOM USB lead- You just have to adjust the timing of the ports on your laptop - it will then show the ABS Controller:

 

 

Although at first VAG-COM couldn't detect the cable - I turned down the COM port settings on the laptop. Go to Hardware - Device manager - Ports (COM&LPT) and Properties of Communication port (USB) usually Com4 and in the advanced settings turn down the 'Latency timer' to 5 - it worked for me.

It depends what COM port you have the connection configured for in VAG-COM, my one only worked on COM4.

 

I'll give that a go, because i always get the 'too many communication errors' error when even i try to connect to the ABS. I can only seem to get VAG COM working on COM3

[Critical_Mass 10]

Had the same problem with a cheap VAGCOM USB lead- You just have to adjust the timing of the ports on your laptop - it will then show the ABS Controller:

 

 

Although at first VAG-COM couldn't detect the cable - I turned down the COM port settings on the laptop. Go to Hardware - Device manager - Ports (COM&LPT) and Properties of Communication port (USB) usually Com4 and in the advanced settings turn down the 'Latency timer' to 5 - it worked for me.

It depends what COM port you have the connection configured for in VAG-COM, my one only worked on COM4.

 

Just given this a go and it worked for me also :thumbleft: So for those of you with the same issue with the ABS and VAG COM, try the above. The lead has to be plugged into the USB port that you normally use, otherwise the port icon wont be on your device manager. :thumbleft:

 

Thanks :D

[Timbo 0]

Go to Hardware - Device manager - Ports (COM&LPT) and Properties of Communication port (USB) usually Com4 and in the advanced settings turn down the 'Latency timer' to 5 - it worked for me.

 

:notworthy: I think I owe you a pint or two. It's not even a serious problem:

 

Control Module Part Number: ABS /ED S

Component and/or Version: TEVES 04

Software Coding:

Work Shop Code:

1 Fault Found:

00285 - ABS Wheel Speed Sensor: Front Right (G45)

35-00 - -

[Critical_Mass 10]

Go to Hardware - Device manager - Ports (COM&LPT) and Properties of Communication port (USB) usually Com4 and in the advanced settings turn down the 'Latency timer' to 5 - it worked for me.

 

:notworthy: I think I owe you a pint or two. It's not even a serious problem:

 

Control Module Part Number: ABS /ED S

Component and/or Version: TEVES 04

Software Coding:

Work Shop Code:

1 Fault Found:

00285 - ABS Wheel Speed Sensor: Front Right (G45)

35-00 - -

 

The left front wheel sensor is dud on mine.

[Timbo 0]

It's probably worth mentioning that I had to upgrade the drivers for the USB serial emulation to actually get the "Latency Timer" option.

[alemay 0]

So it turns out that ecu-testing CAN'T fix the 1995 Corrado VR6 ABS. So..... I took the unit off and carefully worked out where all the connections for the ribbon cable should go. Cut the offending ribbon cable off and rewired all the wires to the plug. A delicate and tricky job but it worked!! If anyone would like pics and a description drop me a line!

 

In hindsight it is probably not necessary to cut off all the wires but to just bypass a couple. Bloody tricky to find the cracks in the cable though.

 

Andy

[larkin 0]

hey alemay,

 

I think i might have a similar problem...

 

heres my abs saga:

 

had my abs light always on and the following errors:

 

Control Module Part Number: 1H0 907 379 D

Component and/or Version: ABS TEVES 04

2 Faults Found:

00276 - ABS Outlet Valve: Left Rear (N136)

00285 - ABS Wheel Speed Sensor: Front Right (G45)

 

so after reading a lot of posts and checking the ecu connectors relays etc etc i replaced my pump and the offending sensors... light went off after startup , happy days or so i thought...

 

about 2 days later the light came on when i was driving, following errors:

 

Friday, 07 November 2008, 19:00:14

3 Faults Found:

00259 - ABS Inlet Valve: Front Right (N99)

00276 - ABS Outlet Valve: Left Rear (N136)

00793 Brake Pedal Position Sensor

 

Since that ive been getting intermittant abs light coming on, usually about 10 minutes into a journey.

 

Friday, 14 November 2008, 17:26:26

00259 - ABS Inlet Valve: Front Right (N99)

00276 - ABS Outlet Valve: Left Rear (N136)

00793 Brake Pedal Position Sensor

 

Monday, 17 November 2008, 08:31:33

2 Faults Found:

00259 - ABS Inlet Valve: Front Right (N99)

00276 - ABS Outlet Valve: Left Rear (N136)

 

Thursday, 27 November 2008, 17:17:12

3 Faults Found:

00259 - ABS Inlet Valve: Front Right (N99)

00276 - ABS Outlet Valve: Left Rear (N136)

00793 Brake Pedal Position Sensor

 

my question is, is my new pump bad too? this seems like too much of a coincidence.. I opened up the old pump and the ribbin cable looks perfect . any tips for checking the ribbon cable?

 

im starting to think that the wiring may be bad between the ecu and the pump or the ecu itself... the pins on the ecu look fine with no obvious water damage..

 

any ideas?

[Timbo 0]

How did you manage to open up your pump by the way? I have a spare that I want to inspect before swapping over but I don't have anything small enough to get at the (presumably) retaining screw on the corner of the plastic cover. When I say small enough I mean something that fits in between the motor and the solenoid block as opposed to the correct size of torx bit.

[alemay 0]

Hi Larkin,

 

The Ribbon cable is tricky to test without knowing the pin layout and the connector is covered in a rubbery stuff so you have to dig it out to see! I'm in South Africa at the moment so don't have access to my wiring diagram I made. If you can wait a couple of weeks I should be able to send you a copy and them you could test it. My fault was also intermittent for a while. when the vehicle was cold it would show and then when it was warm it would go away if I restarted her.

 

in the end I bypassed the ribbon cable completely with normal wires. I did not find anywhere that could give me another ribbon cable. The repair worked initially an then the light came on again but I think this was due to not bleeding the top circuit. I came over to SA before I got chance to do that but will do it on my return! ;-)

 

I also have pic of the repair process that I will put together over christmas for you if it would be useful.

 

All the best

 

Andy

[larkin 0]

cheers andy that would be a great help when you get a chance..

i tested continuity between the plug and the valve pins but get connectivity on all valvepins no matter which plug pin i test so maybe im doing somthing silly..

 

hey timbo i dunno which type of system you have but on mine (teves 04) you just open two allen key screws in the bottom the plastic part that the wire connector plug into and the plastic bottom cover just lifts off so that you can see the ribbon cable..

[larkin 0]

oh yea andy, one more question... how did you bleed the top circuit?

 

maybe we didnt bleed correctly when the pump was changed as it did work initially for a couple of days before i started getting the intermittant fault..

[alemay 0]

Hi Larkin,

 

Apparently you need a pressure bleeder to do that one. It doesn't seem to want to bleed under gravity. I'll have to take it to the garage

 

Good luck

 

Andy

[larkin 0]

hey andy,

did you ever manage to dig out that wiring diagram?

cheers,

barry

[larkin 0]

ok so i opened up the old abs pump tonight to try and see if i could figure out where the fault was..

 

i measured the resistance across all the solenoids/valves and got the following readings...

 

 

Im guessing that one row is the inlet valves and one row is the outlet valves hence the 2 different resistances. What I was hoping though that one of the valves would show an open circuit to suggest which ribbon cable line was at fault. The fact that all the resistances are similar is leading me to believe that maybe this pump is fine and my original problem lies elsewhere on the wiring circuit..

 

Has anyone had any experience rewiring this type of pump before or can give me any more info on what else i can try?

[Gareth_16V 0]

Have you made sure that the ribbon cable itself is good? What you've described above is making sure that the solenoids themselves are not open circuit, but have you tried checking the continuity between the ends of the ribbon? I.e. one probe of the multimeter on a solenoid connection, the other end on the external connector?

 

FInding a resistance across the solenoids does not check the condition of the ribbon.

 

Apologies if I've misread your post, but that's what I'd try first.

[larkin 0]

ok,

So i dug out all the rubber glue where the ribbon cable goes to the plug and tested the continuity from each pin back to its solenoid terminal.

 

They all have perfect continuity, even when i wiggle the cable a bit im still getting 0 ohms resistance between the pin and the solenoid across all lines in the ribbon cable.

 

:shrug:

 

i suppose next stop is to test the loom plug itself and then remove the glovebox etc to test the loom back to ecu...

 

i have the ecu pin testing procedure somewhere..

 

anyone got any tips for testing the loom?

 

anyone know where the abs circuit is earthed?

 

:scratch:

 

cheers,

barry

[larkin 0]

Ok,

I think I have found my problem! One of the wires in the loom seems to be dodgy.

All the valve wires return the correct resistances (7.5 inlet, 3.5 outlet) except for the RH front inlet which was giving me 11ohms..

 

When I wiggled this wire at the pump end of the loom the resistance readings varied from 9ohms to 40ohms! So I think that the wire may be damaged internally and this is what was causing my intermittant abs light.

 

My next step is to somehow replace the wire in the loom. I want to remove the pin from the plug and solder a new wire in place and replace the offending wire back to the ecu

 

I really dont want to botch this and do it right so:

Does anyone know the best way for removing the pin (circled below). Perhaps there is some kind of little tweezers tool or a trick to removing the pins.. if anyone knows how to do this without damaging the plug id appreciate any tips??

[Critical_Mass 10]

Ok,

I think I have found my problem! One of the wires in the loom seems to be dodgy.

All the valve wires return the correct resistances (7.5 inlet, 3.5 outlet) except for the RH front inlet which was giving me 11ohms..

 

When I wiggled this wire at the pump end of the loom the resistance readings varied from 9ohms to 40ohms! So I think that the wire may be damaged internally and this is what was causing my intermittant abs light.

 

My next step is to somehow replace the wire in the loom. I want to remove the pin from the plug and solder a new wire in place and replace the offending wire back to the ecu

 

I really dont want to botch this and do it right so:

Does anyone know the best way for removing the pin (circled below). Perhaps there is some kind of little tweezers tool or a trick to removing the pins.. if anyone knows how to do this without damaging the plug id appreciate any tips??

 

I've tried to get them sort of pins out before from one of the ISO connectors for the stereo, but all i could do is damage the pin. I think ive read on here that someone as managed to remove those kind of pins before. But i had no luck.