ESP Problem

[TONY2215]

Hi there i really need some help with a problem im having with my ESP light coming on. The problem only occurs when i have people in the rear of the car strangely the esp light flashes on and then when i brake the abs kicks in even at low speed. I have had a diagnostic check on it and was told it was a rear abs sensor which i changed and did not solve the problem so i changed the other rear sensor which still has not solved the problem. I lifted the rear seat and have seen a little black box in the the middle which i taped and in turn triggers the esp light on, what is this box?, could it be my problem? Any help would be great as i am now pulling my hair out.
Thank you.
Tony.

VW Passat 03 1.9Tdi

[JustinM3]

You checked the wiring and connector?
Does sound like weight of passengers is moving something on it.

[TONY2215]

Hi, Yep checked the connections etc, running out of ideas now.:aargh4:

[JustinM3]

Maybe check the numbers on it, and google them (if no one hear tells you what unit is etc), should be info somewhere with the numbers.

[TONY2215]

Yep done that too, all im getting is foreign websites no english results at all, i think there german, austrian ect, i think from what i could make out that its some sort of esp control sensor but im not sur, i have trouble reading english sometimes so ive got no chance with that lot.

[snapdragon]

Is it any of these parts?

[TONY2215]

Hi, the diagram is not great but the biggest box shap in the top middle of the diagram looks as if it could be? where is this diagram from?
Tony.

[mrb333]

The box under the back seat is the sensor cluster for the ESP system. It contains a yaw rate sensor (gyroscope) to measure the car's rotation, and an accelerometer to measure lateral acceleration. This box interfaces to the CAN bus, and provides the braking system ECU with the inertial input it needs to operate the ESP system. ESP basically works by comparing the driver's inputs, such as steering wheel angle and throttle position, with the car's actual dynamics as measured by the sensor cluster. If there's a mis-match such as in an understeer or oversteer situation, then the ESP kicks in to correct the situation by automatic braking of individual wheels. The sensor cluster isn't really a serviceable part, so if this is at fault (and it sounds as though it is if tapping it illuminates the dash warning light) then it's probably a replacement job. I'm not sure if this is DIY or if disconnecting/replacing the cluster will cause ECU faults that will require VAG-COM etc to reset.