Z4-forum.com

Hi all,

A week ago, I started a road trip out to the track. About 0.2 miles into the 4 hour journey, the car started acting strange.

1. The "brake" light came up in orange font, the tire pressure light came on in orange font, and the TC off light also came on.

2. The throttle kept sticking for about 0.3 seconds after letting off above 3k rpm (and only under load, not when blipping the throttle).

3. The e-dipstick would not give a reading throught the entire trip. I tried while idling, driving on the highway, city driving, and even on the track. In all situations, the clock symbol would appear for 5 minutes after pressing the button and then it would time out.

Once I got back home, I tried disconnecting the battery and the MAF. I also checked codes, but nothing is showing up (except the usual MAF code after unplugging it, I cleared it and it went away). All of the issues are still present. Any ideas what could have caused all these problems to appear simultaneously and what else I should check?

Thanks in advance.

Item 1 is often associated with a yaw sensor failure, but with all those other issues I think I'd start by checking the battery is good.

If it is not the battery, there are many common grounding points on the car. I included one from an early model Z that shows how the oil sensor is actually grounded with other items on a common point. Sometimes these common grounds can be the source of spurious multiple faults. Although it is unclear why you are not seeing codes. Just another avenue to look for the drawings on and maybe check.

With no codes coming up, check battery and if good to go, I'd consider changing out the ignition switch. Google: BMW bad ignition switch.

Trav wrote: ↑Wed Jan 03, 2024 6:45 pm

If it is not the battery, there are many common grounding points on the car. I included one from an early model Z that shows how the oil sensor is actually grounded with other items on a common point. Sometimes these common grounds can be the source of spurious multiple faults. Although it is unclear why you are not seeing codes. Just another avenue to look for the drawings on and maybe check.

This is interesting and seems to cover a lot of the OPs issues.

enuff_zed wrote: ↑Wed Jan 03, 2024 6:00 pm I think I'd start by checking the battery is good.

Battery is 2 years old, so it should be good, but it's an easy thing to check so I'll give it a go

Trav wrote: ↑Wed Jan 03, 2024 6:45 pm

If it is not the battery, there are many common grounding points on the car. Just another avenue to look for the drawings on and maybe check.

Interesting... thanks for the response. I'll have a look at the ground for the oil sensor and check if all 3 issues are connected to the same ground.

Definitely check the battery, as above,

If it’s an old battery change it, it can look good on the tester but as soon as you put a load on it the voltage drops. It’s easily your cheapest option, there is no guaranteed life I’ve had then go bad a 6 months, others have lasted 8 yrs, todays electronics are very sensitive to low voltage.

Issue ended up being the steering angle sensor being out of calibration. No idea why that would cause a sticky throttle or the e-dipstick to not work, but I'll take it

Rsipad wrote: ↑Sun Jan 21, 2024 9:05 pm Issue ended up being the steering angle sensor being out of calibration. No idea why that would cause a sticky throttle or the e-dipstick to not work, but I'll take it

Can’t answer the dipstick one but if the car thinks the steering angle is excessive it will activate all the dynamic stability stuff which regulates throttle input.