Amber light trifecta

Momoney · Post by **Momoney** » Mon Sep 26, 2022 4:57 pm

Hi All,
Newbie here (but not new to Z4 cars).
I've had my E85 Z4 for about six years and have brought her back from near death by spending absurd amounts of money. Recently, after she sat over the Winter I have just installed new tires and a new battery and some coolant temp sensors. I now have the dreaded three amber lights (parking brake, DSC, and tire). I've read lots of great posts on this forum and have therefore been able to move my diagnostic troubleshooting along a bit. I have a pretty sophisticated diagnostic tool that shows I have wheel speed sensors working. The biggest issue is the 5E40 code with a few other codes.
They are:

Dynamic stability control system (DSC/DXC)
5E40 ABS-DSC: Steering angle implausible

Basic Module
4A GM: Load/consumer shutdown: short circuit to ground
30 GM: K bus: data transmission disturbed

Automatic thermostatic air conditioner (IHKA) my ZED doesn't have an IKHA so not sure why this code is set
51 IHKS:LDH /RDH implausible coding

Instrument cluster (KOMBI_80)
BE KOMBI: Data-filing difference to central light module

Both of my diamond keys have dead batteries so that may explain some of this but I just dont know.

I've tried recalibrating the steering angle sensor but it doesn't make any difference and doesn't calibrate from what I can tell. I also cleared all the codes at least a dozen times but the amber trifecta lights come right back when I drive down the street for about 30 seconds to a minute. By the way, the DSC button works for a hot second until the amber lights come back on a few seconds later.

I say the recalibration doesn't seem to work because the live data shows the steering angle numbers moving all over the place and with the wheel centered it shows -93 or something like that no matter how many times I recalibrate. I'm thinking I have a faulty steering angle sensor. I pulled the sensor off in situ and everything looked okay except there was a lot of what I believe to be dried gray lubricant that I blew off with some compressed air. It was powdery stuff so maybe it's teflon based. Anyhow I cleaned the sensor with electrical cleaner and re-installed, cleared codes and they came back.

I'm pretty much stuck. I believe the only things I have left that I can do is 1) get a wheel alignment, 2) check the yaw sensor (not sure how to check it with diagnostic tool...maybe using live data looking at lateral acceleration???), 3) get new reprogrammed keys, 4) replace steering angle sensor, 5) replace Basic module (ZKE). I hate to just replace stuff without testing voltage or signal or something like this that I can easily do with instruction. I wish I had a shop manual.

Do any of you fine folks have any guidance that you can share?

Zedebee · Post by **Zedebee** » Mon Sep 26, 2022 8:18 pm

Have you read this thread, it’s got a fix about half way through that you may not have tried?
viewtopic.php?t=130939
5E40 and trifecta definitely points to an issue with the SAS, the yaw sensor is a different set of codes and the other codes are likely to be unrelated.

Welcome to the forum, I hope you find some good help here and in return you can tell us what you’ve being doing with your car

Momoney · Post by **Momoney** » Mon Sep 26, 2022 8:29 pm

Thanks so much for the quick response Zedebee. I'll let you know how this progresses.

bigwinn · Post by **bigwinn** » Mon Sep 26, 2022 8:31 pm

Evening

Like zedebee I’ve had painful experiences with steering angle sensors

Happy to help out if I can

Stuart

Momoney · Post by **Momoney** » Mon Sep 26, 2022 8:42 pm

Thanks so much for the quick response Zedebee. I've read that thread like six times. I tried the Toolset32 reset about six times as well. No whirring or click sounds when I did it...and no change. But thank you. Any more ideas are most helpful. I'm wondering if since the numbers jump around while turning the steering wheel eg. 92 to 132 to 185 to -23 to -98 and do not go up or down smoothly without skipping twenty or more numbers or so while viewing live data, if this would be a firm indicator of a bad SAS. Wheel centered also shows 93 like its out of calibration but like I said, the Toolset32 will not calibrate the sensor.

Do you or anyone else know how to check SAS voltage or resistance etc. to determine if the sensor is actually bad before going to all the trouble and expense of replacing the SAS?

bigwinn · Post by **bigwinn** » Mon Sep 26, 2022 8:50 pm

before you replace it which is a PITA do what I did- open it up and bend the prongs in the sensor to create a better contact

I will find the thread where i did this

bigwinn · Post by **bigwinn** » Mon Sep 26, 2022 8:52 pm

viewtopic.php?p=1921718&hilit=steering+ ... r#p1921718

Momoney · Post by **Momoney** » Mon Sep 26, 2022 10:42 pm

Thanks bigwinn...I already used your previous post instructions and did the in situ fix. Took me two weeks to finally get the SAS to pop off the steering shaft with some help of a razor blade to trim the tabs ever so slightly to get then to disengage. Unfortunately it didn't fix the problem. See my original post. The brushes actually looked nice and clean although there was a bunch of dry powdery gray matter in the housing.

Momoney · Post by **Momoney** » Sat Oct 01, 2022 6:47 pm

Bump. Any other help would be great

bigwinn · Post by **bigwinn** » Sat Oct 01, 2022 8:11 pm

Ah that’s a shame

If you are seeing weird numbers on inpa live data after you’ve done that I would now suspect the sas is not working as it should

Momoney · Post by **Momoney** » Sat Oct 01, 2022 10:30 pm

Thanks. That’s all I can figure out too.

Momoney · Post by **Momoney** » Sun Oct 02, 2022 8:35 pm

Bought a used SAS for 50 bucks with shipping. Going to see if that fixes the problem.

bigwinn · Post by **bigwinn** » Sun Oct 02, 2022 8:36 pm

Good luck bud keep us posted

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