Thread: Multiple faults recorded

Sounds like battery or charging...

They tend to go bonkers once the battery dies, or when the battery is even considering dying. So start there if it's old.

Check while running that it's 13+ even with a bad battery the alternator should be able to keep up!

Was the ABS light red or yellow? I had issues with heat affecting my ABS connector expanding it just enough so one of the main power connections weren't allowing enough power through... which would then throw up the 3 amigos... Luckily mine was a connector issue and i've managed to dodgily fix it.

The ABS light was amber.

From my reading of RAVE, it looks like it’s all tied to a DSC fault.
Maybe the precharge pump. That won’t be cheap. But who wants to buy one on spec?

A DSC fault disables the air suspension locking it in highway mode for increased roll stability.

Could just be a random CANBUS error....?

Can also be a SAS fault. Mine was a Xmas tree of lights and a few seemingly unrelated systems , however the SAS wouldn't calibrate so it was the culprit after all.

That sir, is the 3 amigos.

Ive had to repair my ABS module before where it was exhibiting the same thing. Pretty common fault at the age of the car, especially if you take her off road. They have electrical connectors that are fine as hair on the board that can come loose. However, if the fault is recorded as pre charge...

The pump is controlled directly by the DSC module that is bolted to the ASC block. Operation is tested by an expected rise in fluid pressure at the ASC block as detected by the pressure sensor.

That means that there are a few possibilities, the pump does not produce any pressure although it runs, the pressure sensor is faulty, the DSC controller driver has failed or the DSC unit controller is faulty and a false error message is being reported.

The usual symptoms of a failed pre-charge system is that the ABS, ASC and Brake warning lights illuminate as the car is accelerated.

Take a gander at section 2 here!
BMW E38 ABS DSC Brake Failure Repair 735i 740i 750i

My money is on the DSC module itself.

R

Some light reading attached from the irubix archive.

Thanks for the linked article. Last night I cleared the faults that I could - the ABS and EBA warning lights were extinguished. The DSC light couldn't be cleared. The light in the DSC switch is off and won't turn on.

I put an Autologic diagnostic system onto it today and I still have the CAN Bus error on the EAS. I also see a CAN Bus fault on the Steering Angle Sensor. That might need recalibrating.

I did a couple of trips today, each of about 25km/30mins at varying speeds from light traffic to 80km/h on inter-urban roads. There has been no recurrence of the ABS and EBA warning lights coming on.

I will try powering the pre-charge pump directly to see if it runs but that article appears to indicate the pump may not be the problem. I will have to re-read it.

I'm not sure how long the car will stay up if the EAS isn't running.

I just remembered...

Yesterday, when I took the car off charge, and hopped in to start it, I saw the clock rapidly adjusting to the correct time. I hadn't noticed the time previously showing on the clock.

Normally, that only happens if the battery has been disconnected.