Cruise control problem

[JoB01]

Sorry if this is on the wrong spot- this seemed to be the closest topic to the issue I’m trying to figure out-

I’ve got a 2008 E90 M3 with 6MT. Lately, when I engage the cruise control, the needle sets at the correct speed, but the car slows down 5-7mph after I set the cruise control, and stabilized there. For example- I set the cruise control at 50, and the speedometer and car slow to about 45 and hold there. The little indicator bar for the cruise control stays at 50 though.

Has anyone seen this sort of behavior before? I’m thinking it’s either the ECU or a wheel speed sensor. Does anyone know? Thanks in advance!

JoB

[Nazty Naze One!]

I had something where my cruise control would disengage. It would happen sometimes on downhill or just random. I had my friend repair the module. Not sure which one but he said it pertained to the cruise control. Best of luck

[Rajmun340]

Originally Posted by JoB01

Sorry if this is on the wrong spot- this seemed to be the closest topic to the issue I’m trying to figure out-

I’ve got a 2008 E90 M3 with 6MT. Lately, when I engage the cruise control, the needle sets at the correct speed, but the car slows down 5-7mph after I set the cruise control, and stabilized there. For example- I set the cruise control at 50, and the speedometer and car slow to about 45 and hold there. The little indicator bar for the cruise control stays at 50 though.

Has anyone seen this sort of behavior before? I’m thinking it’s either the ECU or a wheel speed sensor. Does anyone know? Thanks in advance!

JoB

Mine does the same since factory. I did euro delivery in 2013 and used CC when travelling in europe. CC was off the same way as you describe.

[Richbot]

Have you tried disconnecting the battery and letting the car sit overnight