My car is sick

[Teavious]

My CSL dash lit up like a christmas tree today and looks to be a wheel speed sensor problem. However, the engine reved by itself though the car was not accelerating - quite scary. Shifted to N to stop the engine from redlining. Any ideas?

[Yanto_csl]

My CSL dash lit up like a christmas tree today and looks to be a wheel speed sensor problem. However, the engine reved by itself though the car was not accelerating - quite scary. Shifted to N to stop the engine from redlining. Any ideas?

The engine revved with no pressure on accelerator ?

[The Gorilla]

Hi,

Quote- ''However, the engine reved by itself though the car was not accelerating - quite scary.........''

Sounds like you could have an issue
with the DBW [Drive by Wire].

The Stepper Motor to the Throttle Bodies
must be getting a signal even though
the Throttle pedal [ potentiometer]
is not registering pedal movement.

Diagnostics is the only way to try and
trace any fault.

Regards,

The Gorilla.

[cantfind1]

agree.....there are 4 TPS on CSL...one in accelerator pedal, one in engine bay on front above oil filter, one under idle control valve and one on the flap motor...ones in the engine bay are most likely to go due to temp extremes.....

[_Nathan_]

The throttle pedal has 2 outputs which describe throttle pedal position, one goes from 0% high volts to 100% low volts, and the other from 0% low volts to 100% being high volts, the sensor on the motor and the throttle rail itself perform the task of current position feedback and again one goes high to low and the other goes low to high. The sensor on the flap doesn't perform a function of either position demand or current position feedback in the closed loop DBW system, simply tells the ECU the position of the flap.

At all times both demand signals (pedal) should read within a few percent of each other, and likewise both feedback signals should read within a few percent of each other, the ECU drives the motor using PWM based on the aim error (difference between desired position - calculated in ECU based on lots of inputs including throttle position - and the feedback position). If either the position demand or feedback position fail their checks (the sensors for that part deviate from each other by too much) then limp home or similar should activated, there is no way a throttle should get pinned open by a failed sensor, think of the law suits and all the stories that would be all over the web of e46s suddenly going WOT on track and killing people.

Also if I may be so bold, how can a car be in gear and rev without accelerating unless a driveline component has failed meaning no drive, and why would putting it in neutral stop it revving if the ECU was driving the motor to WOT, unless the poster meant he was stationary and the lower 6k ish rev limiter kicked in when it was moved to neutral?

Need more info...

[shane@mbtech]

The throttle pedal has 2 outputs which describe throttle pedal position, one goes from 0% high volts to 100% low volts, and the other from 0% low volts to 100% being high volts, the sensor on the motor and the throttle rail itself perform the task of current position feedback and again one goes high to low and the other goes low to high. The sensor on the flap doesn't perform a function of either position demand or current position feedback in the closed loop DBW system, simply tells the ECU the position of the flap.

At all times both demand signals (pedal) should read within a few percent of each other, and likewise both feedback signals should read within a few percent of each other, the ECU drives the motor using PWM based on the aim error (difference between desired position - calculated in ECU based on lots of inputs including throttle position - and the feedback position). If either the position demand or feedback position fail their checks (the sensors for that part deviate from each other by too much) then limp home or similar should activated, there is no way a throttle should get pinned open by a failed sensor, think of the law suits and all the stories that would be all over the web of e46s suddenly going WOT on track and killing people.

Also if I may be so bold, how can a car be in gear and rev without accelerating unless a driveline component has failed meaning no drive, and why would putting it in neutral stop it revving if the ECU was driving the motor to WOT, unless the poster meant he was stationary and the lower 6k ish rev limiter kicked in when it was moved to neutral?

Need more info...

Exactly what I was thinking but I was taking a dump today when I read it, so I couldnt be arsed typing all that on the fricking I phone:hahaha:

[rstoughy]

And so it continues

And so it continues,
Car not really been used since Munich and has received some TLC.
Lepsons refurbished wheels with new genuine badges, new set of Super Sports, new rear spring, new battery, fancy new AUX ipod lead thingie fitted and some fresh flippers back from Mark.
New Recaro SPG waiting to go in when my floor mounts arrive AND
a trip to Germany booked for the end of next week.

My Parrot kit failed and never went off with the ignition so drained EVERY ounce of power from the battery. My guess is that this might have caused the problem with the steering sensor.

Took the car for an MOT yesterday and 5yrds from my door the dash lights up like a festive bush (again)
Had a friend come round tonight with his laptop and it has shown the following,
Steering Angle Sensor - Not Plausible
and Left Front Wheel Speed Sensor.

We are going to try re-calibration of the steering angle sensor using the process set out in the DIS software and I'll stick on a couple of front wheel speed sensors.

Never fails, was hoping for a nice weeks driving to shake it down prior to the trip :banghead:


Still love the old dog though :bigcry:

[billyboysm3]

My CSL dash lit up like a christmas tree today and looks to be a wheel speed sensor problem. However, the engine reved by itself though the car was not accelerating - quite scary. Shifted to N to stop the engine from redlining. Any ideas?

Its 100% a wheel speed sensor only.

[Monkey]

Its 100% a wheel speed sensor only.

+1 for this. Happened to somebody at The Ring if I recall.:thumbs:

[rstoughy]

So,
2 new front wheel speed sensors purchased from BMW yesterday.
Fitted last night and a re calibration of the steering angle sensor and its all good.

The cesil is back :smt055

[northernjim]

Glad to hear it mate :thumbs::thumbs::thumbs:

you will be setting off soon for DN9 to get there on time won't you? :-D:thumbs:

[rstoughy]

Glad to hear it mate :thumbs::thumbs::thumbs:

you will be setting off soon for DN9 to get there on time won't you? :-D:thumbs:

Hahaha Early next Sat Jim so a full 54hrs before the gates open :bigcry: :bigcry: :bigcry:

[Gazza]

Did you change tyres recently? Have you done the pull back the pedal reset thingee?

What's this about ?

[phoenixcsl]

What's this about ?

Drive at 50/60mph + knock the car into neutral, pull both shift paddles back simultaneously, hold them back for 10 seconds (IIRC tho may be less), and then put the car back into gear.

Basically it's a 'soft' reset of the SMG gearbox :thumbs: