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[Taxi_Driver]

Thanks Taxi Driver. For some reason automatics take speed information from gearbox output shaft, not rear wheel sensor, so they have different ABS ECU setup.

This car is my son Jonny's transport. I have it back for its MOT test. He lives in Chippenham. I live in Midsomer Norton, south of Bath. Every Friday I travel to Didcot for golf and tennis; my trade club registration is at Bellingers, Grove, near Wantage, so your country. One of my tennis chums has his Rover 75 service in Swindon.However Downside Motors, Chilcompton, is 3 miles from me, and they have a Tech2 and have helped me in the past.

My worry now is that you had faulty ECU diagnosed, but a new ECU did not cure it. Is the fault still with you?

Must check where Newent and Brackley are.

No....it was diagnosed as faulty ecu....but it was never changed....tried to....but replacement wasnt going to fit.....i havent got the 2.2 anymore.....sold it when it was 6 years old with 150k on it and a long list of problems 

[terry paget]

Fellow OOF members,
                           one more curiosity in this ABS saga.
In the past I have had ABS problems.

In 1996 on a Citroen CX I had an intermittent ABS light coming on for a year, finally traced to a frayed front sensor lead. In 2007 on an Omega 3.2 I had intermittent light coming on, changing ECUs was no help, traced to wandering rear reluctor ring; cured by gluing it in place. IN 2011, Omega 2.5 manual estate, light came on intermittently and with increasing frequency, cured by sending ECU to ecutesting for repair.

In above cases, on ignition switch on ABS light would come on, then go off after 4 seconds. On this car (1999 2 litre manual petrol saloon) the light never came on. Did not worry me, passed 3 MOTs. Reading press this April I learn that bulbs are checked, so I put in a bulb (bulb had been absent). Bulb stayed on. Oh dear.

I had a spare ECU from a scrapped car, so I popped it in. Turned on ignition, ABS light came on, after 4 seconds it went off. Joy. Took for test drive, ABS light come on. Bother. Thereafter ABS bulb stayed on.

Thought I might have mixed up ECUs, so replaced original ECU. Turned on ignition, ABS came on, after 4 seconds went off. Confused. Went for test drive, ABS  light on again. And stayed on.

I do not understand why removing and replacing ECU should give it a brief burst of good behaviour. Could it be removing it from battery power? I have just nipped out, removed negative battery lead, and replaced it. ABS still constantly on. I do not understand it at all.

[Andy H]

The ABS ECU uses a host of tiny aluminium wires (about the size of a human hair) to connect the pcb in the ECU to the multiway connector.

The common mode of failure is for the aluminium wires to fracture. My guess is that unplugging & replugging the ECU caused movement in the pins of the multiway connector sufficient to temporarily make a good electrical contact.

[terry paget]

Thanks Andy H. That makes a lot of sense. I recall a comment on the Catera site along those lines; it said repair can be achieved with aluminium conducting paint. I suppose what ecutesting does for £100 is repair the broken wire. I have noticed on the ECUs they return they have obviously opened the casing and repaired something. Can I do that? Has anybody in the OOF done that?

Are they aluminium wires? I cannot solder those. I hope they are tinned copper, or lacquered copper. Please advise.
. 

[albitz]

Repair of the wires needs to be done by bonding on specialised equipment. As mentioned they are as thin (or thinner) than a human hair,so normal methods such as soldering wont work.Its something that I could possibly get done at work,but the problem is that they are encased in some sort of gel,which needs removing first.
I dont know the process for removing this,so cant find out if repair is a possibilty at work until I find out how to do that.

[terry paget]

Thanks Albitz. that's bad news. The wires to the plug are substantial enough, I hoped the wires from socket to pcb would be similar. I suppose the wretched thing is mass produced by a clever machine, then the pcb to socket section is dunked in some soft setting compound to insulate and support the wires.

I have repaired pcb's in the past by spotting cracked soldered joints and resoldering them. I have repaired breaks in the printed circuits of Omega instrument panels by soldering in light wires where they have burned out. But this sounds beyond me. I wonder if I opened it up and probed around between socket pins and solder points on the pcb whether I could find the failed connection and slip in a light wire. Has no OOF member done that? Replacing central locking microswitches sounds delicate work, but members refer to it as a simple task, like a wheel change.

[Taxi_Driver]

Thanks Albitz. that's bad news. The wires to the plug are substantial enough, I hoped the wires from socket to pcb would be similar. I suppose the wretched thing is mass produced by a clever machine, then the pcb to socket section is dunked in some soft setting compound to insulate and support the wires.

I have repaired pcb's in the past by spotting cracked soldered joints and resoldering them. I have repaired breaks in the printed circuits of Omega instrument panels by soldering in light wires where they have burned out. But this sounds beyond me. I wonder if I opened it up and probed around between socket pins and solder points on the pcb whether I could find the failed connection and slip in a light wire. Has no OOF member done that? Replacing central locking microswitches sounds delicate work, but members refer to it as a simple task, like a wheel change.

From the sounds of it, you would need to use kit that i used many moons ago, when repairing circuit boards....to start with a microscope to actually see what you were doing.....and then a soldering iron small enough.....i used to use a £500 soldering iron which used to heat the tip, smaller than a needle using ultrasonics.....oh and solder paste.
For what i remember the tips of the iron used to burn out every few days.....at iirc £40 a pop to replace them.

[Andy H]

Thanks Albitz. that's bad news. The wires to the plug are substantial enough, I hoped the wires from socket to pcb would be similar. I suppose the wretched thing is mass produced by a clever machine, then the pcb to socket section is dunked in some soft setting compound to insulate and support the wires.

I have repaired pcb's in the past by spotting cracked soldered joints and resoldering them. I have repaired breaks in the printed circuits of Omega instrument panels by soldering in light wires where they have burned out. But this sounds beyond me. I wonder if I opened it up and probed around between socket pins and solder points on the pcb whether I could find the failed connection and slip in a light wire. Has no OOF member done that? Replacing central locking microswitches sounds delicate work, but members refer to it as a simple task, like a wheel change.

From the sounds of it, you would need to use kit that i used many moons ago, when repairing circuit boards....to start with a microscope to actually see what you were doing.....and then a soldering iron small enough.....i used to use a £500 soldering iron which used to heat the tip, smaller than a needle using ultrasonics.....oh and solder paste.
For what i remember the tips of the iron used to burn out every few days.....at iirc £40 a pop to replace them.

The last time anyone used BBA Reman I think it cost them around £100 and the part was returned working and guaranteed in less than a week.

I consider myself to be quite proficient at soldering (I started helping my father to solder fiddly little components as a six year old) but I am realistic about my (in)ability to solder aluminium or to remove the goo so I wouldn't hesitate to send my ABS ECU to BBA if it fails.

[Taxi_Driver]

Thanks Albitz. that's bad news. The wires to the plug are substantial enough, I hoped the wires from socket to pcb would be similar. I suppose the wretched thing is mass produced by a clever machine, then the pcb to socket section is dunked in some soft setting compound to insulate and support the wires.

I have repaired pcb's in the past by spotting cracked soldered joints and resoldering them. I have repaired breaks in the printed circuits of Omega instrument panels by soldering in light wires where they have burned out. But this sounds beyond me. I wonder if I opened it up and probed around between socket pins and solder points on the pcb whether I could find the failed connection and slip in a light wire. Has no OOF member done that? Replacing central locking microswitches sounds delicate work, but members refer to it as a simple task, like a wheel change.

From the sounds of it, you would need to use kit that i used many moons ago, when repairing circuit boards....to start with a microscope to actually see what you were doing.....and then a soldering iron small enough.....i used to use a £500 soldering iron which used to heat the tip, smaller than a needle using ultrasonics.....oh and solder paste.
For what i remember the tips of the iron used to burn out every few days.....at iirc £40 a pop to replace them.

The last time anyone used BBA Reman I think it cost them around £100 and the part was returned working and guaranteed in less than a week.

I consider myself to be quite proficient at soldering (I started helping my father to solder fiddly little components as a six year old) but I am realistic about my (in)ability to solder aluminium or to remove the goo so I wouldn't hesitate to send my ABS ECU to BBA if it fails.

I couldnt solder the stuff now i used to repair back then.....looking through a microscope.....using a 'needle' type iron, rock steady hands.....and also chatting to a fellow worker at the same time 

I also used diagnose what was wrong with the pcb......using a pc with test harness connected to the pcb to send signals to the pcb and using a scope to diagnose where the signal wasnt getting thro......doubt if i could that either now