Porsche Enthusiasts Club Forum

Mate has a late 89 plate 2.7, on turning the ignition key ABS warning light comes on & stays on. I assume this isn't a wheel sensor & is more likely ABS pump or ECU. A few questions:
Is the ABS pump & ECU combined?
How easy is the fault finding? Is it worth getting it scanned by someone with a Bosch scanner?
Any one done the repair & any suggestions?

Not combined - assuming its the same as my turbo.
ECU is by your right knee when you're sat in the drivers seat behind the carpet - easy to get at and change.
Pump is behind the drivers side front wheel - not so easy to get at and rather more expensive to fix.
Guess which mine was!
Could just be a fuse or relay if you're really lucky.

From memory...

The ABS ECU runs a quick self test on power up, it checks for open circuit sensors and if it is getting power on the right pins. If it sees the sensors as not being open circuit and it has power and earth on the right pins, it turns off the light.. if not, it keeps the light on.. So check the ABS fuses and the relay in the fuse box.

Once it see's you have hit about 5mph for the first time since the ignition switch has switched on, it then powers up the pump until the pump pressure sensor returns a high pressue signal. If the pump is found to be open circuit, or does not register pressure within a couple of seconds, or if it sees one of the 4 sensors returning no signal or a signal at a different speed to the rest, it then brings the light back on. If it brings the lamp on once you

I think it is also wired in, so that if the ECU is not there, or not responding, it will leave the lamp on all the time.

If you need an ABS ECU to test, let me know, I can loan you one.

Hello

I've got 2 ecu's i suspect they're both broken.

I've tested everything and i have the correct voltages at each pin.
The abs pump runs when i energise the relay 28
The abs solenoid relay works and when give it power pin 27 there is cottage present on the 3 returns from the solenoids Also the light goes out when i give an earth.27
I have alternator voltage..
I have voltage when beans pedal depressed.
I have close to 1 k ohms on each sensor..

I bought an ecu of a guy on here Austin. I suspect it doesn't work.

Any advice is appreciated.

Thank you.

Ashley.