2004 525i manual. Limited power abs/traction lights and messages and jerky driving if apply to much throttle and car running flat? Have changed vanos and throttle assembly?? Please help

First you'll need to take it to have DTC's - diagnostic trouble codes check to find out what part of the system is at fault ! Could have a sensor , control module ,or wiring problem !
Traction Off Indicator The traction off indicator, which is a LED located on the traction control switch, illuminates only when the traction control switch has been pressed and released, disabling traction control. It is important to note that a traction fault does not illuminate this indicator and that there is no relationship between this indicator and the traction fault message.
Traction Fault Message The IPC displays the traction fault message when either of the following instances occur.
?€¢
The EBCM detects a malfunction that requires traction control to be disabled. The EBCM sends a serial data message to the IPC requesting that the message be displayed.

?€¢
The IPC detects a loss of serial data communication with the EBCM

Traction Control System (TCS)
When drive wheel slip is noted while the brake is not applied, the EBCM will enter traction control mode.
The EBCM uses a 5-volt pulse-width modulated (PWM) signal to request the PCM to reduce the amount of torque to the drive wheels. The PCM reduces torque to the drive wheels by retarding spark timing and by commanding the throttle actuator control. The PCM uses a 5-volt PWM signal in order to report to the EBCM the amount of torque delivered to the drive wheels.
You would need a factory grade scan tool to check data PID's - parameter identification , all the sensors work within a specific voltage range 1- 5 volts an you can see this on a good scan tool !
The Traction control is part of the ABS system an there a several DTC possible
DTC B0827 DTC B0828 DTC B2745 DTC C0035 DTC C0035 or C0040 DTC C0040 DTC C0055 DTC C0110 DTC C0191 DTC C0201 DTC C0220-C0229 DTC C0240 or P0856 DTC C0244 or P1689 DTC C0245 DTC C0267 or C0268 and C067 or C068 DTC C0550 DTC C0899 DTC C0900
You best bet is to take it to a qualified repair shop !

You

Traction control helps by controlling the engine power to the drive wheels to prevent wheel spin. When traction control is OFF then you can apply all power to the drive wheels and it could cause loss of control and or wheel spin.

Hello anber...the "Trac OFF" light comes on when there is a malfunction in the ABS because the traction control system uses the ABS sensors and other components to apply brakes to the slipping wheel so that the other wheel will get some power. Not as good as a limited-slip diff, but better than nothing. With the ABS reporting a fault, the Traction Control cannot function, and its computer disables it--hence the light. Fixing the ABS should fix the Trac problem. I would start by checking the sensors and making sure the master cylinder is full of brake fluid. I hope this helps.

The traction control system senses wheel spin from either drive wheel. Excessive spin sensed by the ABS sensor will force the wheel that is spinning to brake to avoid loss of traction. You could have a faulty ABS sensor (wheel speed sensor) As far as the engine "cutting off" Do you mean that it shuts off completely or you cannot accelerate?

The traction control uses the speed sensor in the transmission and the wheel speed sensors to determine wheel spin. If a wheel spins braking is applied to it so that the power can be transferred to the other wheels. At some point the ECU detected a gross disagreement between the sensors and so as a precaution has entered into a limp home mode. On some systems if the fault is in error it can be cleared by putting the car into drive and moving forward a meter, putting in reverse and going a back a meter and doing this three times. If one or other of the sensors are faulty this process will not allow the error to be cleared. You need to check or have checked the error codes and the speed sensors.

Standard Vehicle Stability Assist™ (VSA ®) with Traction Control and Brake Assist Vehicle Stability Assist (VSA) is an electronic stability control system that works in conjunction with the Pilot's drive-by-wire throttle and its 4-channel ABS systems to enhance controllability while the vehicle is accelerating, braking, cornering or when the driver makes a sudden maneuver. VSA functions by applying brake force to one or more wheels independently while also managing the throttle, ignition and fuel systems to help the vehicle maintain the driver's intended path of travel.

The VSA system constantly analyzes data from seven sensors that monitor wheel and vehicle speed, steering input, lateral G forces and yaw rate. It compares the driver's control inputs with the vehicle's actual response. Whenever the actual response falls outside of a predetermined acceptable range, VSA intervenes with a corrective action.

For instance, if VSA detects an oversteer condition, the system may apply braking force to the outside front and rear wheels to counteract the unintended yawing effect. In the event of understeer, VSA may apply braking to the inside rear wheel while reducing engine power to help return the car to its intended course. VSA also provides a limited-slip differential effect for the front wheels by applying braking force to a slipping wheel, thereby redirecting driving force to the wheel with more traction.

There is a button on the lower left part of the dashboard that says "VSA". Push it and the triangle will dissappear (this should only be turned off if you are using a spare tire that is smaller than the rest of the tires).

Good luck.

Standard Vehicle Stability Assist™ (VSA ®) with Traction Control and Brake Assist Vehicle Stability Assist (VSA) is an electronic stability control system that works in conjunction with the Pilot's drive-by-wire throttle and its 4-channel ABS systems to enhance controllability while the vehicle is accelerating, braking, cornering or when the driver makes a sudden maneuver. VSA functions by applying brake force to one or more wheels independently while also managing the throttle, ignition and fuel systems to help the vehicle maintain the driver's intended path of travel.

The VSA system constantly analyzes data from seven sensors that monitor wheel and vehicle speed, steering input, lateral G forces and yaw rate. It compares the driver's control inputs with the vehicle's actual response. Whenever the actual response falls outside of a predetermined acceptable range, VSA intervenes with a corrective action.


For instance, if VSA detects an oversteer condition, the system may apply braking force to the outside front and rear wheels to counteract the unintended yawing effect. In the event of understeer, VSA may apply braking to the inside rear wheel while reducing engine power to help return the car to its intended course. VSA also provides a limited-slip differential effect for the front wheels by applying braking force to a slipping wheel, thereby redirecting driving force to the wheel with more traction.

There is a button on the lower left part of the dashboard that says "VSA". Push it and the triangle will dissappear (this should only be turned off if you are using a spare tire that is smaller than the rest of the tires).

Good luck.

The traction control system is controlled through the Anti-lock brake system. The way it works is if one of your wheels starts spinning the ABS applys the brake to that wheel to transfer power to the oppsite wheel that is getting traction. If your ABS is bad then your Traction control won't work. To check it I would find a parking lot on a wet day. In an open space mash in the gas. if you hear the ABS system kick in and you don't squall the tires then your good. My guess is you won't. What I would be worried about is will my ABS work. When checking the traction control is a good time to check the ABS. Acclerate to around 15 mph, then mash the brake as your live depended on it. If you hear a motor run and feel a vibration or grind in the brake peddal, then it works.

big problem with egr intake passage plugging up need to remove upper intake check passage