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Discussion Starter #1
driving a ML430 2001.

whenever i try to drive the car hard i.e. floor the car, step on the gas hard. and try to accelerate faster

my car stalls and the bas/esp light comes on.

if i restart the car. all is normal and i can drive until i try to drive the car hard.

any idea why this is happening? and how can i fix it.

it is a real safety hazard. especially while merging. plus it is also very embarrassing.
 

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Purple Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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It be anyone of a number of things. Fuel delivery system including filter and pump.
The MAS giving bad info to the ECU but that should give you a check engine light.

The one thing that has me guessing it may not be either of things I first posted is that you said the BAS/ESP comes on. When that circuit is activated by the sensors the first thing the computer does is to cut way back on power and start applying braking at different corners of the truck depending on whether it is trying to correct understeer or oversteer. The power being cut is probably is what is causing the stalling.
This is just a guess, but I am leaning towards a bad wheel speed sensor or yaw sensor that for whatever reason is sending a faulty signal to the computer. It could even be the computer that is acting up. There is a separate processor from the ECU that handles the BAS/ESP functions.

IMO the best thing to do would be to spend a half hour labor at a reputable german shop or dealer and have them plug in to all the diagnostics. Believe it or not it took 10 days to solve a BAS/ESP problem on our truck. They just finally replaced everything after never finding the source of the problem. Three weeks later it was determined to be a yaw sensor. The factory checked over each part and then told the SM at our dealer what was wrong. At least they put me in a an E class for the ten days the ML430 sat in the dealership. They even called in one of MBs roving uber techs. It was his call to swap all electronics relating to the BAS/ESP ans also traction control for good measure.

One thing that I wish they had not done in 2001 was to take away the ESP switch. If they had not done that you could turn off the ESP circuit and see if that made a difference. MB claimed it was safer to remove the switch, but never gave me any reason why.
 

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CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Noodles - 11/6/2005 7:58 PM

It be anyone of a number of things. Fuel delivery system including filter and pump.
The MAS giving bad info to the ECU but that should give you a check engine light.

The one thing that has me guessing it may not be either of things I first posted is that you said the BAS/ESP comes on. When that circuit is activated by the sensors the first thing the computer does is to cut way back on power and start applying braking at different corners of the truck depending on whether it is trying to correct understeer or oversteer. The power being cut is probably is what is causing the stalling.
This is just a guess, but I am leaning towards a bad wheel speed sensor or yaw sensor that for whatever reason is sending a faulty signal to the computer. It could even be the computer that is acting up. There is a separate processor from the ECU that handles the BAS/ESP functions.

IMO the best thing to do would be to spend a half hour labor at a reputable german shop or dealer and have them plug in to all the diagnostics. Believe it or not it took 10 days to solve a BAS/ESP problem on our truck. They just finally replaced everything after never finding the source of the problem. Three weeks later it was determined to be a yaw sensor. The factory checked over each part and then told the SM at our dealer what was wrong. At least they put me in a an E class for the ten days the ML430 sat in the dealership. They even called in one of MBs roving uber techs. It was his call to swap all electronics relating to the BAS/ESP ans also traction control for good measure.

One thing that I wish they had not done in 2001 was to take away the ESP switch. If they had not done that you could turn off the ESP circuit and see if that made a difference. MB claimed it was safer to remove the switch, but never gave me any reason why.
 

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Sorry but the best I can say is good luck. My wifes ML had this problem but hers would not stall just would not shift when the BAS/ESP light would come on. After 5 trips to get it repaired we just gave up. They did replace the computer (numerous times) and the connections. Maybe you just have a loose connection or a intermittent short. But as someone stated earlier have someone look at the car and find the root cause.
 

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Hmm, I'd start with the usual suspects like a defective brake light switch, although your symptoms appear to be a bit different....

http://www.benzworld.org/forums/forums/thread-view.asp?tid=1166641&posts=14
 

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Discussion Starter #6
ok today i had the "esp off" button turned on, so the esp was off. and to test it out. i stomped on the gas. the same thing happened again. bas/esp light comes on and my car stalls, have to restart it.

this is so frustrating. i probably gonna bring it into the dealer. i never went before, what type of charges will they charge you? and how much would it approx. cost to bring it in?
 

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Your vehicle is most likely going into Traction Control and it's trying to reduce engine torque by request torque reduction to Engine Controller. It's probably happening because of wheel speed sensor problem. The wheel speed sensors are most likely reading bad signals, but ESP unit is not logging failure. If it was logging failure, it would disable ABS and you would've seen the ABS lamp. So, check the wheel speed sensors.
 

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Purple Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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I agree that is one of the possibilities in my post, as to how much it will cost. Well the diagnosis should be under one hour of labor. The sensors are not very expensive and are a DIY job if the dealer puts it in it will not be much labor.
 

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1999 ML320
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I had this happen literally 15 minutes ago. I replaced my factory stereo today and in the process, per the crutchfield instructions, disconnected the battery. Well disconnecting the battery doesn't make the BAS/ESP system happy. I called MB and talked to a tech who told me to:

1) Turn on the truck
2) turn the steering wheel all the way to the left, then all the way to the right, then all the way back to the left (my ml320 makes a higher pitched sound when it reaches the extremes of turning)

I turned the car off then back on again and it worked...no more BAS/ESP light in the far left, no more yellow triangle, no more near death experiences as I pulled out of the driveway! Hope this helps some, if not good luck!
 

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Purple Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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That reset procedure has to be done after the battery is disconnected everytime. My dash looked like a friggin Xmas tree after I had changed the battery.

Did you make sure you had your radio code handy?
 

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One the two occasions I've had to replace my battery I took the precaution of providing a 12V back-up power feed into the aux 12V outlet.
Thus all the electronics were kept powered while the main battery is disconnected and so no need to reset or re-enter radio codes etc.
The back-up power was provided from a 12V compressor which had an internal battery and came with a power jumper cable intended to be plugged into a cigarette power outlet.

Of course this process is likely not recommended by MB and you have to be careful that all possible electrics are turned off and not to cause any shorts.
 

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ml500 w163 2002
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i have the exact same problem as he, and that's why i was curious what he did. basically i try to accelerate hard but gradual without allowing the car to downshift, and suddenly the bas/esp light comes on and the car won't accelerate anymore. as a matter of fact when i press the gas it seems it even slows down more compared to just letting off on the gas to coast to a stop after this point. I have to pull over and restart the car to get it running.

i checked my codes and get a throttle position sensor error p0221, which i already replaced the TPS connected to the gas pedal, and it didn't help.
 

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RUEY220, did you try to reset the BAS/ESP?

1) Turn on the truck
2) turn the steering wheel all the way to the left, then all the way to the right, then all the way back to the left

I cleaned my battery this weekend, unhooked it from both the pos and neg; when I hooked it back up I noticed the BAS/ESP light on when I started the truck........I performed the reset above, be sure to turn the wheel all the way to each side........ no more BAS/ESP light......... didn't try and drive anywhere because I knew I could reset the system by using the steering wheel reset...... just had to come in and look it up on the site.......
 

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RUEY220, did you try to reset the BAS/ESP?

1) Turn on the truck
2) turn the steering wheel all the way to the left, then all the way to the right, then all the way back to the left

I cleaned my battery this weekend, unhooked it from both the pos and neg; when I hooked it back up I noticed the BAS/ESP light on when I started the truck........I performed the reset above, be sure to turn the wheel all the way to each side........ no more BAS/ESP light......... didn't try and drive anywhere because I knew I could reset the system by using the steering wheel reset...... just had to come in and look it up on the site.......
yes i've done this...i think it may be the acceleration lateral sensor, i've checked other threads that have similar problems to mine, seems like it may have solved the problem...i'll let you know if it comes back.
 

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yes i've done this...i think it may be the acceleration lateral sensor, i've checked other threads that have similar problems to mine, seems like it may have solved the problem...i'll let you know if it comes back.
code P0221 is about the engine comp. having difficulty monitoring certain function. It does not specify that the TPS is the problem. Either someone misinformed you or the scanner you used is giving a generic fault which might pertain to another vehicle, but it isn't this one.
 

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code P0221 is about the engine comp. having difficulty monitoring certain function. It does not specify that the TPS is the problem. Either someone misinformed you or the scanner you used is giving a generic fault which might pertain to another vehicle, but it isn't this one.
P0221, Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance Problem is shown when you look it up on all OBDII reaers.

I believe when the broken Lat Accelaration sensor throws off the ESP, ESP cuts the throttle body from giving air to the motor which is basically what the gas pedal does, and then the ECU sees the pedal still being pressed while the ESP cut it off. This causes P0221 to come up because OBDII is mostly engine ECU stuff and OBDII scanners does not apply to convenience/proprietory safety systems for particular car manufacturers. I am just guessing but if my problem is solved then that's probably what's going on.
 

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Read the info. on code P0221. This is straight from M/B. Many things have to be monitored before making a decision.
 

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Read the info. on code P0221. This is straight from M/B. Many things have to be monitored before making a decision.
the codes you pulled up are for p0203 which monitors the sensors that tell you if you have a p0221. I found these on my search for p0221. Basically it's a checklist checking for another checklist of errors. As it states, it is a fault in the monitoring for p0221 before p0221 even occurred.

Mine is a p0221 fault which shows the list in p0203 is working ok. You can compare these to like a scenario where a radiator thermostat is working correctly but your thermometer on the dash being broken. The thermometer may say the car is overheating but the car is actually not. The thermostat may be doing its job to open the radiator and let the coolant flow, but then again there's a fault in the monitoring of the radiator and coolant temp.

In comparing my case to above, it would be like my radiator is actually overheating and not a "malfunction" of the sensors that say the car is overheating, which is like P0203.
 
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