View Full Version : Please Help Low Speed Limp Mode in 1st gear on Audi A3

11-06-2018, 04:28 PM
Hi All, I have an issue with my partners Audi A3 1.6 petrol BGU… while in first gear pulling off the engine seems to cut power, limiting it to 2000rpm ish as soon you go into 2nd it does the same sometime but soon after clears and the power is back on for the rest of the journey, so when you pull away from the junction there is no issue. If you switch the ignition off it goes thought the same process. Disconnecting the clutch G476 Hall Effect sensor removes the problem (MIL on eventually) or if you disconnect the two front ABS Sensors (sensor and magnetic pick up was checked, it looks all ok). I did the forum search but the trail goes cold on this particular issue. Any views on this would be welcomed...

18-06-2018, 10:57 AM
I haven’t given up as yet on this issue. My thinking is 2 front ABS speed sensors send signals to ABS control from there via CAM bus to ECU. ECU sees ‘some kind of input at low speed ‘and cuts the power for short period of time and then everything is ok again.

Might be ABS controller issue sending wrong data to ECU or ECU itself? It could be high resistance in any of the wires:- CAM bus or Speed sensor wires.

(This fault only happens just once after stating up. Rest of the journey is all ok. And disconnecting both front sensors fixes the issue)

Would anyone know under what conations ECU cuts power (limp mode)?