2F4F & P0503

mthew_m · 04-03-2022, 09:59 PM

Having what is seemingly a very uncommon problem - Code 2F4f, 'Vehicle Speed Plausibility', which sets P0503 check engine light code. Really stumped on this one, and finding almost no information online - any guesses?

Wheel speed sensors have been replaced, no change. Not sure how it behaves on the DME side, but on the OBD side, after that code is cleared, it will trigger a 'pending' code relatively quickly, but it will stay as pending for a long, long time, unless the car is accelerated at full throttle + high rpm, which will pretty much immediately send it to a full code.

Just as strange, on this '07 328i 6MT, it constantly has 2F6C exhaust gas flap activation, even though there is no exhaust flap. Also has 2DED & 2ADF which, luckily, aren't CEL codes. Really stumped here. The car isn't useable, because it can't be inspected & registered in this state unless the computer shows emissions readiness, which it won't with a pending code. Any previous discussions I can find involve modified computers, which this vehicle doesn't have, and I can say fairly confidently it never had (purchased CPO in '08). Stumped & don't know where to turn, other than to take it to the dealer and just get ready to pay a heap of money for them to fire parts at it.

n0ah305 · 04-03-2022, 10:43 PM

Quote:

Originally Posted by mthew_m

Having what is seemingly a very uncommon problem - Code 2F4f, 'Vehicle Speed Plausibility', which sets P0503 check engine light code. Really stumped on this one, and finding almost no information online - any guesses?

Wheel speed sensors have been replaced, no change. Not sure how it behaves on the DME side, but on the OBD side, after that code is cleared, it will trigger a 'pending' code relatively quickly, but it will stay as pending for a long, long time, unless the car is accelerated at full throttle + high rpm, which will pretty much immediately send it to a full code.

Just as strange, on this '07 328i 6MT, it constantly has 2F6C exhaust gas flap activation, even though there is no exhaust flap. Also has 2DED & 2ADF which, luckily, aren't CEL codes. Really stumped here. The car isn't useable, because it can't be inspected & registered in this state unless the computer shows emissions readiness, which it won't with a pending code. Any previous discussions I can find involve modified computers, which this vehicle doesn't have, and I can say fairly confidently it never had (purchased CPO in '08). Stumped & don't know where to turn, other than to take it to the dealer and just get ready to pay a heap of money for them to fire parts at it.

I've been trying to fix his 2F4F code for months. I can't find a fix online however I noticed my code comes when going on the highway. Not sure if you experience something similar. I also have a bad wheel speed sensor plausibility code. I bought two new OE speed sensors and I can't get the rear right speed sensor to work. I thought the 2F4F was due to a bad rear right sensor but I guess they are two separate issues. Please let me know if you find a fix to this. I'll update if I find a fix as well

gbalthrop · 04-03-2022, 11:22 PM

2F4F & P0503 relate to Right-Rear Wheel Speed Sensor. If you have a Scan Tool or Software such as INPA/ISTA which can read Fault Codes or Live Data in DSC Module, you should see an issue with either direction or speed in that Wheel Speed Sensor signal as received by DSC. Here is BMW Fault Code Lookup Fault Info Sheet for 2F4F:
https://bmwfault.codes/XMLDiagView?d...IAMgA5ADAANAA=

OP, what are Last-7 Characters of VIN so I can provide wiring diagrams from ISTA, including Exhaust Gas Valve info. If you had INPA, you could connect to DME (MSV80) and determine if your vehicle has Exhaust Gas Valve (AKG), and if so, activate it (turn it off/on). I don't know WHICH N51/N52 had such a valve (my 3/2007 build 328xi N52K does NOT) but apparently some DID. Check fuse F74.
George

mthew_m · 04-04-2022, 09:20 AM

Thank you for the info! Last 7 of the VIN are ND55254. It's a fairly early build car, I think officially Nov 2006, but, I've found parts on it that were manufactured as early as July 2006. I've had it hooked up to one of the scanners at one point, drove around the block and verified that all the wheel speed sensors are putting out data, and the readings were appropriately close. And, I don't watch my speedometer 100% of the time, but, I have made a point to watch it when I know the light is going to come on, and have not noticed any inconsistency. But, I know it may be damped/etc. Something I forgot to add, cruise control does not work, even before the CEL comes on, I just get '---' instead of a speed setting.

For the exhaust flap, I don't have the time, energy, desire, etc to deal with that, I only presented the information in case it could somehow lead to getting the CEL code fixed so I can get the car back on the road. I will check for the fuse when I get home, but, I've looked at the exhaust, and haven't seen anything that looks out of the ordinary. It's wild, but it's looking more and more like a good condition 328 with 89k miles is headed to the scrap yard. Don't want to do it, but, the options seem slim at this point.

04-03-2022, 09:59 PM	#1
mthew_m Registered 1 Rep 3 Posts Drives: E90 328i Join Date: Aug 2021 Location: Raleigh, NC iTrader: (0)	2F4F & P0503 - Any Guesses? Having what is seemingly a very uncommon problem - Code 2F4f, 'Vehicle Speed Plausibility', which sets P0503 check engine light code. Really stumped on this one, and finding almost no information online - any guesses? Wheel speed sensors have been replaced, no change. Not sure how it behaves on the DME side, but on the OBD side, after that code is cleared, it will trigger a 'pending' code relatively quickly, but it will stay as pending for a long, long time, unless the car is accelerated at full throttle + high rpm, which will pretty much immediately send it to a full code. Just as strange, on this '07 328i 6MT, it constantly has 2F6C exhaust gas flap activation, even though there is no exhaust flap. Also has 2DED & 2ADF which, luckily, aren't CEL codes. Really stumped here. The car isn't useable, because it can't be inspected & registered in this state unless the computer shows emissions readiness, which it won't with a pending code. Any previous discussions I can find involve modified computers, which this vehicle doesn't have, and I can say fairly confidently it never had (purchased CPO in '08). Stumped & don't know where to turn, other than to take it to the dealer and just get ready to pay a heap of money for them to fire parts at it.
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04-03-2022, 11:22 PM	#3
gbalthrop Brigadier General 2738 Rep 4,065 Posts Drives: 2007 328xi E91 Join Date: May 2017 Location: Fairfax Co, VA iTrader: (0)	2F4F & P0503 relate to Right-Rear Wheel Speed Sensor. If you have a Scan Tool or Software such as INPA/ISTA which can read Fault Codes or Live Data in DSC Module, you should see an issue with either direction or speed in that Wheel Speed Sensor signal as received by DSC. Here is BMW Fault Code Lookup Fault Info Sheet for 2F4F: https://bmwfault.codes/XMLDiagView?d...IAMgA5ADAANAA= OP, what are Last-7 Characters of VIN so I can provide wiring diagrams from ISTA, including Exhaust Gas Valve info. If you had INPA, you could connect to DME (MSV80) and determine if your vehicle has Exhaust Gas Valve (AKG), and if so, activate it (turn it off/on). I don't know WHICH N51/N52 had such a valve (my 3/2007 build 328xi N52K does NOT) but apparently some DID. Check fuse F74. George
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04-04-2022, 09:20 AM	#4
mthew_m Registered 1 Rep 3 Posts Drives: E90 328i Join Date: Aug 2021 Location: Raleigh, NC iTrader: (0)	Thank you for the info! Last 7 of the VIN are ND55254. It's a fairly early build car, I think officially Nov 2006, but, I've found parts on it that were manufactured as early as July 2006. I've had it hooked up to one of the scanners at one point, drove around the block and verified that all the wheel speed sensors are putting out data, and the readings were appropriately close. And, I don't watch my speedometer 100% of the time, but, I have made a point to watch it when I know the light is going to come on, and have not noticed any inconsistency. But, I know it may be damped/etc. Something I forgot to add, cruise control does not work, even before the CEL comes on, I just get '---' instead of a speed setting. For the exhaust flap, I don't have the time, energy, desire, etc to deal with that, I only presented the information in case it could somehow lead to getting the CEL code fixed so I can get the car back on the road. I will check for the fuse when I get home, but, I've looked at the exhaust, and haven't seen anything that looks out of the ordinary. It's wild, but it's looking more and more like a good condition 328 with 89k miles is headed to the scrap yard. Don't want to do it, but, the options seem slim at this point.
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