I've been having intermittent 4WD engagement issues on this S3 thing. The Haldex system under the rear seat always made a noise from when I bought the car and after a bit of research figured a 'new' primary pump would be best bet to cure that. The ESP light was also always on, but after renewing the clock spring and repairing the lateral G sensor on the steering column I was able to clear those faults. Ran the recalibration sequence then I only get the ESP light after the car starts moving. Fault codes on Haldex for lack of CANbus connectivity with ECU & ABS controller remained and I hoped to find some broken wires between the spare wheel area and the Haldex controller but that wasn't it either.
20 odd quid on eBay found me another pump but it turned out the noise is from the Haldex controller itself... and a bit of google-ing finds that pretty consistent. Apparently the Gen-1 Haldex controllers are prone to oil creeping past gaskets & seals to start playing havoc with the electronic module.
So 100 odd quid finds me a spare haldex controller... connect that one to the car and it comes with fault code 65535 'internal error' which is another sure sign of oil ingress - this one had oil spilt all over the connections and the body was filthy - it cracks me up when car breakers neither bother to clean anything or test anything and happily ask for three figure sums - its a total crap shoot. I did get a refund on that one after a prolonged discussion, but anyway.
So another 120 quid found another Haldex controller plus another pump. Plugged that in today and guess what - same 65535 error code on the controller. Externally this one looked a lot fresher so I felt the need to investigate - at risk of damaging the thing further, but hopeful that a good clean internally would at least give it some electrical sanity. There is a crappy little O-ring which seals the oily side of the stepper motor from the electronic side of things... when that O-ring fails then oil creeps into the clean side and you can imagine all sorts of chaos.
So anyway, I found an O-ring from a spares box that was a nice looking fit so I took a chance on that and kept going with the clean up job... the next bit is a bit embarrassing and expensive, but its a lesson to us all - when I took off the metal cover for the PCB I was confronted with some god awful snotty gloop that I assumed was potting compound which had been broken down by the Haldex oil... so I set to cleaning that up which was a bad idea as its terrible stuff to scrape off. It was only after a few minutes cleaning that I noticed a bunch of tiny single strand wires from pads on the PCB to the connector pins on the edges. I had broken several off as I had never seen that kind of connectivity before.
Sorry to be gross, but if you can imagine something the size of pubic hairs from the board to the plug pins then you get the general idea. So deep breath - with some conductive pubes and my magnification spectacles I can fix these. But then it gets worse... while moving over the board with a soldering iron that I was waiting to heat up - a large dollop of solder falls off and splats itself over multiple tracks making some short circuits... ok deeper breath - I can mop that up... turns out I could not - trying three different irons, a hot air system, two different types of mop... the solder just wouldn't get hot enough to melt as all the heat was transferring through the PCB into metal chassis of the controller.
So the only sensible recourse of action (after 3hrs of dicking around with this thing) was to hit it the PCB with a cold chisel and fatal force from a 2lb lump hammer. That certainly put it well past any chance of corrective surgery but at least I got rid of some anger. What a piece of shy-ite (pardon the language)... So I am 220 quid in the hole and all I have is two spare Haldex pumps (both those tested fine at least), plus the non PCB half of this controller. The S3 was supposed to be some low stress fun and experience for track days - I want to be spannering the S2, not this thing.
Just realised its Friday 13th so perhaps today wasn't the day to venture inside this fiendish device - I have learnt more about Haldex in the past month than I ever wanted to know. The irony is that the Haldex controller on my car was fitted with the PowerTrak insert for permanent 4WD engagement so mine doesn't even need the stepper motor to work, but because CANbus isn't working then the pump never activates (as the ECU cannot tell Haldex about rpm) and so 4WD doesn't engage - and the ESP light comes on. I am tempted to just bypass the Haldex controller and hot wire the pump on in the meantime, so at least I get 4WD although ESP will always be off. I could probably code the ABS controller & ECU for 2WD to kill the nagging ESP light, but I bet that only creates more hassle than its worth.
I have to put this down to some expensive hands-on research... and waffling on here about it might give me a better avenue to explore.
I am sure the more recent Haldex systems are a vast improvement on the 1st generation - but yeah, give me Torsen any day !
I have photos if anyone cares, but for now its time for a beer.
20 odd quid on eBay found me another pump but it turned out the noise is from the Haldex controller itself... and a bit of google-ing finds that pretty consistent. Apparently the Gen-1 Haldex controllers are prone to oil creeping past gaskets & seals to start playing havoc with the electronic module.
So 100 odd quid finds me a spare haldex controller... connect that one to the car and it comes with fault code 65535 'internal error' which is another sure sign of oil ingress - this one had oil spilt all over the connections and the body was filthy - it cracks me up when car breakers neither bother to clean anything or test anything and happily ask for three figure sums - its a total crap shoot. I did get a refund on that one after a prolonged discussion, but anyway.
So another 120 quid found another Haldex controller plus another pump. Plugged that in today and guess what - same 65535 error code on the controller. Externally this one looked a lot fresher so I felt the need to investigate - at risk of damaging the thing further, but hopeful that a good clean internally would at least give it some electrical sanity. There is a crappy little O-ring which seals the oily side of the stepper motor from the electronic side of things... when that O-ring fails then oil creeps into the clean side and you can imagine all sorts of chaos.
So anyway, I found an O-ring from a spares box that was a nice looking fit so I took a chance on that and kept going with the clean up job... the next bit is a bit embarrassing and expensive, but its a lesson to us all - when I took off the metal cover for the PCB I was confronted with some god awful snotty gloop that I assumed was potting compound which had been broken down by the Haldex oil... so I set to cleaning that up which was a bad idea as its terrible stuff to scrape off. It was only after a few minutes cleaning that I noticed a bunch of tiny single strand wires from pads on the PCB to the connector pins on the edges. I had broken several off as I had never seen that kind of connectivity before.
Sorry to be gross, but if you can imagine something the size of pubic hairs from the board to the plug pins then you get the general idea. So deep breath - with some conductive pubes and my magnification spectacles I can fix these. But then it gets worse... while moving over the board with a soldering iron that I was waiting to heat up - a large dollop of solder falls off and splats itself over multiple tracks making some short circuits... ok deeper breath - I can mop that up... turns out I could not - trying three different irons, a hot air system, two different types of mop... the solder just wouldn't get hot enough to melt as all the heat was transferring through the PCB into metal chassis of the controller.
So the only sensible recourse of action (after 3hrs of dicking around with this thing) was to hit it the PCB with a cold chisel and fatal force from a 2lb lump hammer. That certainly put it well past any chance of corrective surgery but at least I got rid of some anger. What a piece of shy-ite (pardon the language)... So I am 220 quid in the hole and all I have is two spare Haldex pumps (both those tested fine at least), plus the non PCB half of this controller. The S3 was supposed to be some low stress fun and experience for track days - I want to be spannering the S2, not this thing.
Just realised its Friday 13th so perhaps today wasn't the day to venture inside this fiendish device - I have learnt more about Haldex in the past month than I ever wanted to know. The irony is that the Haldex controller on my car was fitted with the PowerTrak insert for permanent 4WD engagement so mine doesn't even need the stepper motor to work, but because CANbus isn't working then the pump never activates (as the ECU cannot tell Haldex about rpm) and so 4WD doesn't engage - and the ESP light comes on. I am tempted to just bypass the Haldex controller and hot wire the pump on in the meantime, so at least I get 4WD although ESP will always be off. I could probably code the ABS controller & ECU for 2WD to kill the nagging ESP light, but I bet that only creates more hassle than its worth.
I have to put this down to some expensive hands-on research... and waffling on here about it might give me a better avenue to explore.
I am sure the more recent Haldex systems are a vast improvement on the 1st generation - but yeah, give me Torsen any day !
I have photos if anyone cares, but for now its time for a beer.
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