First of all, I want to thank everyone who took the time to create these guides and help others here! Great work!
I’ve performed the mods for Auto High Beam and ACC on my 2021 Rebel, as described here.
The Auto High Beam works perfectly and is a great improvement for driving at night!
My vehicle already comes with Factory Front Collision Warning (FCW).
Now to the actual issue:
I successfully installed the ACC control unit on the steering wheel and made the following changes using AlfaOBD:
The vehicle detects the car in front and tries to maintain the set speed. It follows the vehicle ahead at the selected distance, just as it should.
But here’s the issue:
As soon as the vehicle in front slows down, my truck tries to slow down too — it downshifts accordingly.
However, if downshifting alone isn’t enough, the truck continues approaching the vehicle ahead — but it does not brake!
When it gets too close, ACC fails and I get the following error messages in the cluster:
Only after turning the vehicle off and restarting can I activate ACC again — but with the same issue.
Here’s what I’ve tried so far:
FCW is enabled in the vehicle menu with active braking.
The vehicle does detect braking vehicles on the road and gives a warning — however, I haven’t yet tested active braking myself.
The ParkSense reverse braking works perfectly.
Does anyone know what the issue could be or how to fix this?
Thanks in advance for your help!
I’ve performed the mods for Auto High Beam and ACC on my 2021 Rebel, as described here.
The Auto High Beam works perfectly and is a great improvement for driving at night!
My vehicle already comes with Factory Front Collision Warning (FCW).
Now to the actual issue:
I successfully installed the ACC control unit on the steering wheel and made the following changes using AlfaOBD:
- Cruise Control Present: No
- Type of Adaptive Cruise Control (ACC) system present: ACC with Stop & Go
- P/T Chassis Net: ACC Adaptive Cruise Control: Enabled
The vehicle detects the car in front and tries to maintain the set speed. It follows the vehicle ahead at the selected distance, just as it should.
But here’s the issue:
As soon as the vehicle in front slows down, my truck tries to slow down too — it downshifts accordingly.
However, if downshifting alone isn’t enough, the truck continues approaching the vehicle ahead — but it does not brake!
When it gets too close, ACC fails and I get the following error messages in the cluster:
- ACC Unavailable – Service Required
- Auto Emergency Braking (AEB)/ACC Unavailable – Service Required
Only after turning the vehicle off and restarting can I activate ACC again — but with the same issue.
Here’s what I’ve tried so far:
- Disconnected the battery for several hours to perform a hard reset
- Cleaned the camera lens responsible for detection
FCW is enabled in the vehicle menu with active braking.
The vehicle does detect braking vehicles on the road and gives a warning — however, I haven’t yet tested active braking myself.
The ParkSense reverse braking works perfectly.
Does anyone know what the issue could be or how to fix this?
Thanks in advance for your help!
