Timm's BMW E31 840ci - ASC and ABS Lights Illuminated
New method that requires no Diagnostics shown in second section
It’s freezing, I’m reversing out from work and this pair light up
That pair means that just when you need it most, the Anti Skid Braking system and the Automatic Stability Control system has fizzled out
- and in freezing conditions that means skidding and wheel-spinning rather than pointing the right way and safely coming to a stop.
Typical. But I’ve had this before about five years ago on my previous 840ci and that was the ABS pump motor which had seized up. So, at
the weekend I fired up INPA and a quick diagnosis shows:
This is quite a common problem, especially as the ambient temperature drops during winter - and my failure was on the first day this
year when the temperature dropped below freezing. The reason these pumps give up is that they are rarely used - they only fire up for a
couple of seconds soon after the car is started and they grind to a halt completely if the car is rarely used.
Sometimes running the pump for ten seconds or so will get it going again. And this was the case with my 840ci this time. When I fired
the pump up via diagnostics the first time it hardly turned to start with - but by the third time it was going like a rocket - a bit noisy but
running well enough to do its job. So here’s how it is done.
You are going to need BMW diagnostics, I’m using INPA which was bought from Ebay and included the interface and the 19-pin round
plug that matches the standard under-bonnet diagnostic connector. The software is loaded on a Windows 8 Laptop and connected to the
interface via a USB cable. Here’s the diagnostic socket on the 840ci:
Right, Laptop fired up, my batteries are fully charged on the car, so ignition to position II (instrument warning lights ON) and fire up INPA
- here’s the sequence, select Older Models (F2), E31 Chassis, ABS/ASC MK5, and then F6 (Activate)
From the screen above - pressing F5 should activate the ABS pump. Mine ran very slowly to start with, but after a couple of goes it
seemed as happy as Larry - a bit noisy, but running well enough.
For a change I’ve done a video, this goes through the complete routine and shows how long the pump runs for - and the activation of
the ASC throttle butterfly at the end of the pump run.
I’ll update later to report if this has any lasting effect!
Update 1 week later - all OK so far
Update 2 weeks later - all OK - I ran the pump again while checking engine data and the pump sounds so much better!
Update 3 months later - all OK still, haven’t needed INPA to run the pump either
Second Method (No Diagnostics Needed)
Well, it’s almost a year later and the ABS and ASC warning lights are back on - this time I am at work and have no diagnostics to hand - so
I am trying a new method. All I need to do is to close the contacts on Relay K94
Here’s how it’s done:
All done - Time for a Cup Of Tea