E70 goes into trailer mode before coding- no brake lights?

[spyro235]

All, thanks in advanced for any information you could share.

I've just installed the factory hitch kit, including wiring and module. Installed as per the BMW service instructions. Yesterday I towed for the first time, and was happy to see that the running lights and blinkers worked fine. However, with the application of the brakes, the lights didn't change. The rear lights on the trailer are fully LED. I'm trying to make an appointment with a local coder to get my car coded for the trailer module, but it almost seems as though it's got the coding already. The car goes into trailer mode, turns off the rear PDC, and gave me trailer brake light warnings. Is this a result of the the trailer only having LED's, or because my car isn't coded properly yet?

[ryan5034]

I think that’s normal. I had the same result before getting coded.

[spyro235]

That's great news! Bad news is that my mechanic forgot his laptop and can't clear a short code for me/ code the module, because the short code needs to be fixed before the AHM can be coded in. So.... I guess I'm going to try to get Tool 32 and ISTA/P working, and learn to do it myself. Need to tow for 250 miles on Saturday, and the car will be in the shop all Friday having a wheel bearing done.... So i guess it's today, or driving all that distance without brake lights on the trailer... I'd really prefer not doing that.

[ryan5034]

Best of luck. You could try one of those remote coding guys. Never done it myself.

I’ve had good luck towing with my X5.

[smassey321]

Originally Posted by spyro235

That's great news! Bad news is that my mechanic forgot his laptop and can't clear a short code for me/ code the module, because the short code needs to be fixed before the AHM can be coded in. So.... I guess I'm going to try to get Tool 32 and ISTA/P working, and learn to do it myself. Need to tow for 250 miles on Saturday, and the car will be in the shop all Friday having a wheel bearing done.... So i guess it's today, or driving all that distance without brake lights on the trailer... I'd really prefer not doing that.

Tool 32 won't help you and ISTA/P is a difficult install. Try basic coding with ncs expert. Get the standard tools software here https://www.bimmergeeks.net/downloads

Follow these instructions Getting Started - Coding E90 | Coding E90

Add +AHMU to VO/FA in CAS and FRM

Change AHM config values below

LAENDERVARIANTE_AHM
us
CCMELDUNG_ABRISS_AHV
cc_04bh
CCMELDUNG_FEHLER_AHM
cc_04bh
CCMELDUNG_VERRIEGEL_AHV
cc_04bh
START_CCM
klemme_15
TYP_AHV_SG
keine_ahv
SL_BEI_KZL_AKTIV
nicht_aktiv