Automatic Transmission and Yellow Brake Warning Lights In & Out. Meh.

[billschusteriv]

Happened last Thursday morning while driving to work:



Car was driving fine. Only noticable changes to the car after the lights came on was an audible ding, the shift points changed, and the cruise control refused to activate. I was a little more cautious... but the brakes were still responsive... transmission was shifting through all of the gears...

After four cycles of the ignition in the morning/afternoon, the lights went out.

Later that evening, the lights came back in and went out after two cycles of the ignition.

I was driving in rush hour traffic... stop and go... periods of acceleration (in sport mode) and hard stopping.

The brake fluid was changed last October and remains topped off.

No other indications of any issues.

Path forward:

I talked with my indy mechanic, who told me to stop by so we could see what (if any) codes came up. Was going to buy a code reader, but he recommeded I do some more research to make sure it does what I want. Definately an OBDII reader - which may not read transmission codes?

So... transmission issue... brake system issue... both systems are tied together...

We'll read some codes... and see what's going on... only final thought we had was that it could be early warning/failure of the stop light sensor being that I was doing a lot of braking.

Any other thoughts?

I'll try to keep this updated as things progress.

[danewilson77]

Possible wheel sensor issue?

Droid! Srs Legitness!

[billschusteriv]

Good thought - I look into checking the sensors also. Assuming you mean wheel speed/pulse sensors?

Alternatively, considering how the system is designed and dependant on other modules... this could be an issue with other modules... I didn't get any ABS/DSC warning lights, so I didn't consider those at first.

[danewilson77]

Good thought - I look into checking the sensors also. Assuming you mean wheel speed/pulse sensors?

Alternatively, considering how the system is designed and dependant on other modules... this could be an issue with other modules... I didn't get any ABS/DSC warning lights, so I didn't consider those at first.

Yes......that's what I was referring to....and yes....the other two lights are usually attendant as well.

[mikeyb74]

I've had that transmission light on before but that was from forgetting to plug the MAF back in. Just strange.

[danewilson77]

The MAF, gave you the transmission warning light?

Droid! Srs Legitness!

[mikeyb74]

The MAF, gave you the transmission warning light?

Droid! Srs Legitness!

Strange I know.

One of my friends with a very high mileage an 04 325i kept having the transmission error warning light coming on acouple of weeks ago. He would pull over shut the carr down and restart it. The light would go off. He said the car felt like it was in limp mode. No power over 2K rpm. He also had the CEL, ABS, BRAKE, Brake Lining, and DSC warning lights all on. The car ended up needing a engine replacement. Something to do with the way the engine was running was causing the trans error warning light to come on.

[billschusteriv]

I've had that transmission light on before but that was from forgetting to plug the MAF back in. Just strange.

The MAF, gave you the transmission warning light?

Droid! Srs Legitness!

Mmmmmm. Good data point.

Considering that it clears itself, I can only assume that it is some intermittent/bad condition, connection, or fault.

Still need to get the codes read. Will drop by mechanics house tomorrow night if all goes well.

Strange I know.

One of my friends with a very high mileage 325i kept having the transmission error warning light coming on acouple of weeks ago. He would pull over start the car down and restart it. The light would go off. He said the car felt like it was in limp mode. No power over 2K rpm. He did have a CEL, ABS, BRAKE, and Brake Lining all on. The car ended up needing a engine replacement. Something to do with the way the engine was running was causing the trans error warning light to come on.

^hopefully not this. I already replaced the engine and front diff. I'm expecting the trans will die eventually...

[danewilson77]

Strange I know.

One of my friends with a very high mileage an 04 325i kept having the transmission error warning light coming on acouple of weeks ago. He would pull over shut the carr down and restart it. The light would go off. He said the car felt like it was in limp mode. No power over 2K rpm. He also had the CEL, ABS, BRAKE, Brake Lining, and DSC warning lights all on. The car ended up needing a engine replacement. Something to do with the way the engine was running was causing the trans error warning light to come on.

I will ask again, when is the last time the fluid and filter were changed in his auto?

Droid! Srs Legitness!

[mikeyb74]

It could be a sensor, plug, or connector loose.