164 Q4 ABS problem (warning light on)

[sancho164]

My 3.0 V6 from 1990 also has inadequate brakes (also now, with non-functioning ABS).
First changed the brake fluid and brake hoses with original TRW. Nothing. Absolutely nothing.
We repaired the rear brakes regulator and the pedal is now not that hard as it was.
There is a feeling, that you are pressing the pedal, harder, and harder, but the car is goooooing and gooooing...
I cant describe it very well, but you know it.
The 2.0 Super has good brakes. It has small, 257mm discs, which can overheat easier than the TD/V6 brakes.
But the feeling when braking is not bad. Some of the Supers has very very sensitive brakes, some - not that much.
The last chance to improve the old V6 brakes, is the brake pump and servo from Super.
It is scarefull to drive the V6 with almost 200hp, with brake system like that!

[riprex]

Did you bleed the system properly? You have to put some weight in boot to bleed rear axle. Also you have to adjust that proportional valve otherwise too much brake force will go to rear axle.

[AlfaWhiz]

I need some more help on this guys. Getting kind of lost at the moment.

So I've replaced the N51 group THREE TIMES already. I'm on the third unit now. The last one was completely dead, no light on dash, no response. The one currently in is said to be working (got it from a trusted source here from the forum).

However, the ABS light is on and the "paper clip" diagnosis shows codes (12), 37, 36, 19, (12). Note the 36, which is not even on the error code list.

Code 37 means "brake switch (H3) deffective", my brake lights work correctly though. I assume as per wiring diagram to check connection between pin 2 of connector G273 and pin 1 of connector G124 (and pin 9 of fusebox G1).

Code 36 I have no idea, not on the code list. I will try to read it using the F/L Tester, as soon as I get correct modules.

Code 19 is what I had with all previous units as well. It says "faulty solenoid valve relay". I'm getting very suspicious though, as it's highly unlikely all the units I had share the same problem (not impossible though).

I've tested the relays and they get 12v on pins 87 and 12v on pins 86 on key power. When testing on my workbench with 12v battery attached, the right-side relay (looking as if looking at the car engine from the front) got 12v on pin 86 for only 1-2 sec, then 0v.

The left relay clicks when mounted in-car and key is turned. The right one does not.

All tests on a stationary vehicle with engine turned off. The warning light lights up immediately after turning the key and stays on.

How are the two relays supposed to work? As I mention, only the left one is clicking, but I measure voltage on both of them. One is engaging and the other one not. I suppose the relay which is clicking on the left side is the solenoid valves relay and the other is the pump motor relay, which is supposed to be powered by the solenoid valve relay and get a signal to engage from the CPU (as per the wiring diagram). So the fact it's not clicking when stationary would be correct.

Why code 19 when the solenoid valve relay is clicking?

At the moment all hydraulic lines are disconnected from the ABS pump and the fluid is drained, because I was trying to swap the pump for another unit. After I did, the codes are still there, no luck.

Is there a possibility that some short etc. is causing the code 19 to appear (and destroy the N51 unit) as soon as I plug it into my car?

Any ideas? How to go on debugging this further?

Any tips would be highly appreciated.

[AlfaWhiz]

So I had a lot of time to run some tests and also I've used the Fiat/Lancia Tester to diagnose the ABS. I'll report my findings below.

First and foremost, errors read through the F/L Tester do not match errors from the flashing light diagnosis, as identified through the pre-facelift error code table. Codes from flashing light diagnosis ended up being something else than what is listed in the table. I believe it was a brake switch and a safety relay.

Unfortunately I did not get a real good chance to note them down, because as I reconnected the ABS a couple of times and ran the diagnostics again, the only remaining code was for the "ABS safety relay" listed as intermittent. I believe it matches code 19 from the flashing light diagnosis, but am not sure, as the code has been cleared by the tester and paperclip diagnosis shows no more error codes.

Now, most importantly, the codes are clear, tester shows no codes "no errors found", flashing light diagnosis shows no codes (only blinking 12 repetitively), BUT MY ABS LIGHT IS STILL ON. The light turns on with the ignition and does NOT extinguish afterwards, does not matter if the car is started or stopped. The car has not been moving. The light flashes correctly (I presume) with the paperclip diagnosis, but does NOT go out after ignition turned on, despite listing no errors.

Any ideas?

Second question: where the hell can I find the G272 connector, ABS fuse and the ABS safety relay? The location as listed in the connector diagram, right of the glove box, is unfortunately not where they are in my Q4 (1994 model year). Instead, space right to the glove box under the aircon vent is occupied by 3 or 4 large connectors attached to a drawer-like mechanism, allowing them to be pulled out for access. Nothing more is in there, can't see anything else. Where can I find the ABS fuse, relay and G272?

I hope to get some good ideas from you guys, thanks.

[Alfan]

Code 36 is clutch pedal fast idle switch defective, giving a signal of disengagement of engine or not.

G272 is the plug connecting to the pins at the yellow arrow in the attached photo. The pink arrow is the pump motor relay. I have finally found someone who could take the unit apart, so I hope to have this fixed during summer.

If you haven't downloaded the ABS manual, I suggest you do, as all this info is there. Also Wilco's program can connect to the ABS, I think you have only mentioned using the F/L tester and the flashing light methods.

I hope this helps

[AlfaWhiz]

Thanks Allan, I think the biggest news is that you have someone who can take the thing apart. Keep us posted! I would gladly send one of my non-functioning units to get it sorted out. As a side note, opening it is not a problem. I have tried that as well with some disturbing results (very easy to brake the hair-like wires attaching the housing to the circuit board, one has to access them through a service flap first before separating the two halves). It's the fixing what's inside that is difficult.

You can be spot-on with code 36. My clutch switch was hanging loose above the pedal as one of the retaining clips was broken. Now all zip-tied in place nicely. I don't know what to trust, the F/L Tester, flashing diagnosis or Wilco's software? They seem to contradict each other to some extent.

Brake switch and clutch switch signal are registered correctly, checked with the tester. Code 19 is then either the "ABS safety relay" or the solenoid valve relay, perhaps they are the same thing? They should not be the same, but who knows.

I made a mistake in my post, I'm looking for G124 together with what is called by the F/L tester an "ABS safety relay" and ABS 15A fuse.

And remember, I get no codes with the tester and paperclip diagnosis, but the ABS light is still on.

[Alfan]

G124 is in there somewhere...

In all the documents I have, code 19 is the brake switch.

[AlfaWhiz]

What it looks like in mine is what is on the 2nd picture: three big connectors side by side (G166, G170, G149) and it sure looks like G124 should be in there somewhere... Will have another look at the spaghetti wiring. The other photos show G125 which should be the ABS fuse holder together with G124, but interestingly not the photo with the setup similar to what I see on my car.

If code 19 is indeed the brake switch, it should be solved now. ABS gets correct signal.

In such case, why is the warning light on despite having no error codes stored in the memory?

I guess I will have to go through fault tests A and B and cut-open the solenoid valve relay. Does it really have to be cut open, or can the cover be lifted up somehow?

[Alfan]

You may be able to pry it up (it has tabs at the bottom), but it may crack when trying that.

The PDF file I attached, show how the G124 connector looks like. The light being on could be a simple electrical problem and not related to the ABS functionality, but now I am guessing...!

[AlfaWhiz]

Time for an update. Not much luck. Current status is as follows.

- ABS throws error code 19 (paperclip diagnosis), or "Sicherheitsrelais" (F/L Tester M30A module in German), which most probably is the same as "solenoid valve relay" error code as per the non-Q4 fault code table (code 19 from Q4 ABS manual is listed as brake switch, which is definitely functional; F/L Tester receives the signal correctly through the M30A module and MA12A).

- I have opened both relays without damaging them. I can see the left relay when looking from in front of the car (solenoid valve) engaging after ignition key turned on. The right relay (motor pump) does not engage.

- Engaging the right relay (motor pump) manually does nothing, no sound, pump not moving. After a couple tries the left relay disengages as well. A bit puzzled about that, but pump may not be enabled to work as ABS is "not active" as per the F/L tester due to code 19 "safety relay" error.

- Active diagnosis of pump motor with the F/L Tester and M30A completes without error.

Any ideas?

[Alfan]

Ok, can't say if the manual is correct for the Q4.

Do you know if the pump motor works? Have you applied 12V to it directly?

[AlfaWhiz]

Hmm, I haven't tried to apply 12v to the motor directly. It's worth checking, although the error suggests something else. How exactly do I do that? Where are the connectors directly for the pump motor?

[Alfan]

I hope these photos makes sense. Only apply 12V for a short time to check it!

[AlfaWhiz]

Oh, ok, so the positive terminal is visible once the tray for the electronic module is removed. I will try it.

Still, no idea how to approach the "solenoid valve relay" / "safety relay" / code 19 problem...

Edit: the diagnosis of the solenoid valve relay basically says to check for correct relay operation, which as far as I can see operates the coil correctly (is clicking when key turned). I will re-check connection between pin 87 and battery power. Pin 86 gets 12v as the relay is engaging correctly. If the relay is functional the manual just says "replace group N51". It's a bit depressing, since I've replaced N51 2 times already. The original one had the same problem, faulty solenoid valve relay, the next one was completely dead (no light, no nothing), the current one again has faulty solenoid valve relay. Is it just bad luck?

I would love to get my hands on a known, 100% functional N51 to see if the problem would be gone, although the one I currently have was said to be tested and fully working as well.

[AlfaWhiz]

I did apply 12v from ca. 10 A power supply to the pump motor directly and it did only just tick slightly, but my power source was dimming. I assume pump motor needs more amps and is powered directly from the battery, and not through the 10 A ABS fuse.

Still does not explain the code 19 "faulty solenoid valve relay" or "faulty safety relay". Gonna need another N51 unit I guess.

[Alfan]

I used my battery charger, which can also be used as a direct 12V supply.

[AlfaWhiz]

Still no luck with my ABS... ABS throws error code 19 (paperclip diagnosis), or "Sicherheitsrelais" (F/L Tester M30A module in German), meaning "faulty solenoid valve relay". Currently a module which was provided by Alfist is installed and Alfist has confirmed it was functional. Still the same error in my car. Any ideas how to debug it highly welcome.

[Integrale evo]

How is this tested, is it a test when starting up and if its register that 12v is missing on coil or on relay output? Most be a problem with "missing" voltage before the abs unit. AS the problem is There with all the module you have tried

[Alfan]

I cannot recall if you have followed the manual test protocol for the ABS, but it would seem relevant to do.

I have gotten new relays for the ABS unit, which I hope will be mounted soon, then I will try it out and hope that the problem is solved. Photos will follow of the unit with the new relays.

[Engine]

On some ABS units the relays are soldered on, on others they can be replaced like any relays.

The ABS unit reads back essentially the voltage after the relay and on that basis it sets a faultcode. I'm not 100% sure it reads the high current (so the wire to the solenoid) but that is what I expect. If the ABS unit sees no effect there, it blames the relay. However if the relay did switch over but there is no power supply for the high current the ABS unit would see the same.

If you can identify which of the relays it is you can try to feel if it works. you should be able to feel the click. After key-on the ABS cycles through all the relays and valves quickly for the diagnostics. It may be triggered only after you reach like 3km/h which you can simulate by lifting up the front axle and let someone operate the car.
If the relay feels fine then check if it gets a supply at all. Just by checking with a multimeter. It probably requires a min. 11V or 11.5V for the ABS unt to claim it is OK.


Edit: got rid of most of the spelling errors... I write in too many languages and get mixed up

[Alfan]

I have checked the relays, which led me to get them replaced. That is of course relevant to try out, which is also why I asked about running through the manual test procedure (again maybe...)?

The ABS version on the Q4 have welded relays, not soldered, so it requires some work to do that (a retired aeroplane engineer within electronics is helping me out). I hope this will solve it for me - nothing strange in a relay going bad after 20+ years, at least.

[Alfan]

I got the welded relays replaced on 2 units and have tried both in my car. In both cases I get error code for 'Solenoid right front & rear left' now, where originally it was 'Pump motor failure'. This also means that the ABS still does not work, I have tested it on road.

I have not yet had time to look into this, but the ABS error list states to measure resistance on these valves, so that would be the next step.

Here are photos of some of the work done and a link to the relays, I bought.

Original relays:
Bosch 0 332 002 411 50Amp

Replacement:
Bosch 0 332 002 192 50Amp
Hella 4RA 003 437-111 60Amp

https://www.autodoc.de/hella/936506?utm ... alo_atd_de" onclick="window.open(this.href);return false;

[AlfaWhiz]

Great work Alfan on replacing those relays! Very good to know it can be done.

I will tackle ABS in my car once again as soon as I get the car back from the workshop. Could you guys tell me how should I check both of those relays exactly? Assuming I have them open, and I'm looking at them from the front of the car, between which points should I measure what voltage exactly?

Second point, if we assume that the module I have, including both relays, is NOT defective (as confirmed by Alfist here from the forum), what else could potentially cause this "Sicherheitsrelais" defect? Some wiring, but where?

[Alfan]

I guess checking wires to the unit is a good thing to do (I think the test cases describes what to do there). This should also show you, what is suppose to happen when applying 12V in the right places, to see if the relays behave correctly or not, that was what I did - trial & error way

[AlfaWhiz]

The only puzzle with the troubleshooting from the manual is the connector G124 they mention. To this day no one is able to tell me where it should be located. There is nothing like this in the area below the passenger-side air vent, so its location is still a mystery to me.

I will do all the steps again once I get the car back from the workshop where new engine mounts have been fitted and oil pan and all peripherals resealed, and after current steering rack leak problem is solved.