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  #1  
Old 05-21-2019, 08:12 PM
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cpnwrench cpnwrench is offline
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No start 3 codes wont clear.




Hi folks,
This is an issue that has me totally stumped……

I have searched all internet search engines, and sites.. I see others have run into issue including X5 with 4.4L motor (M62Tu). but no one has posted solution.

Saw various posts on this issue on both the ‘FEST and on BimmerForum…… But no one has replied with a solution, seen post from BimmerForum INDISCHROT and gearhead999, Blakey2000, but not one has posted what the solution was.

I am reaching out to all as I just don’t want to have my beauty towed into a shop only for them to tell me that’ll be $1500.00 dollars ……

Here is the issue….
P0120 throttle / pedal position sensor A circuit pending

P0123 throttle / pedal position sensor A circuit high input pending

P0223 throttle / pedal position sensor / switch B circuit high input

P0103 mass or volume air flow circuit high input pending

The first three CANNOT clear with my OBD-II scanner ,but the last one will clear and return after the first attempt to start .

I have attempted the battery disconnect for 30 minutes + ( connecting the POS cable and NEG cable together).
Then re-connecting Battery and leaving key on in the #2 position for 2 minutes, then turn off and wait 2 minutes and attempt to start.

No GO JOE.

I have triple checked using meter, all the wiring, engine compartment is oil free and clean. Measured all voltages, all resistances, all appear correct.

Am thinking maybe Ecu is shorted out for MAF signaling or something.

Anyone know what causes those codes to NOT go away? ( ECU?)

Wits end here guys.

Cpnwrench


appreciate feedback.
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  #2  
Old 05-22-2019, 05:02 AM
ou18 ou18 is offline
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Quote:
Originally Posted by cpnwrench View Post



Hi folks,
This is an issue that has me totally stumped……

I have searched all internet search engines, and sites.. I see others have run into issue including X5 with 4.4L motor (M62Tu). but no one has posted solution.

Saw various posts on this issue on both the ‘FEST and on BimmerForum…… But no one has replied with a solution, seen post from BimmerForum INDISCHROT and gearhead999, Blakey2000, but not one has posted what the solution was.

I am reaching out to all as I just don’t want to have my beauty towed into a shop only for them to tell me that’ll be $1500.00 dollars ……

Here is the issue….
P0120 throttle / pedal position sensor A circuit pending

P0123 throttle / pedal position sensor A circuit high input pending

P0223 throttle / pedal position sensor / switch B circuit high input

P0103 mass or volume air flow circuit high input pending

The first three CANNOT clear with my OBD-II scanner ,but the last one will clear and return after the first attempt to start .

I have attempted the battery disconnect for 30 minutes + ( connecting the POS cable and NEG cable together).
Then re-connecting Battery and leaving key on in the #2 position for 2 minutes, then turn off and wait 2 minutes and attempt to start.

No GO JOE.

I have triple checked using meter, all the wiring, engine compartment is oil free and clean. Measured all voltages, all resistances, all appear correct.

Am thinking maybe Ecu is shorted out for MAF signaling or something.

Anyone know what causes those codes to NOT go away? ( ECU?)

Wits end here guys.

Cpnwrench


appreciate feedback.
Does the car even attempt to turn over? Or when you turn the key it just shows dash lights and doesnt even attempt to engage the starter?
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1998 White 740 I (MY 06/98) Daily Driver (when not apart)
1997 Black 740IL (w\ badass Phone in console) Donor Car Now
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  #3  
Old 05-22-2019, 02:57 PM
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cpnwrench cpnwrench is offline
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Location: Texas now, workn G'vlle SC
 
Join Date: Oct 2008
Posts: 422
Mein Auto: 92 525i


Yeah, I was thinking to fast and forgot to put in that qualifier,

turn the key, car wants to start, gets fuel, spark, and almost stays running, then dies in like 2 seconds.

Update: OHMMETER/Voltmeter tests..

Getting +5 volts (VDC) on the GROUND wire from ECU to MAF ( PIN 3 on MAF, PIN 9 on X6003 at ECU)

Am thinking the ECU is shorted.

Cheers!

cpnwrench
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  #4  
Old 05-22-2019, 11:51 PM
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cpnwrench cpnwrench is offline
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Location: Texas now, workn G'vlle SC
 
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Mein Auto: 92 525i


Well, I found problem.

ECU ( DME 7.2) fried.


took ECU out of car, pulled off back plate, and the stench unmistakable. Burnt Electronics.

continuity tests confirmed multiple grounds open in ECU that should be 0 ohms to case and pin 6 of X6003

found pedal sensor ground open, MAF ground open, multiple heated oxy sensor grounds open.

all those pins should be reading 0 ohms to case or pin 6.

new (USED) ECU/DME on way. hope i can just drop in ( after i do continuity test) and turn car on to test voltages outputs.

all I am reading telling me i have to get a replacement ECU re-programmed for my car.

Is this 100% true?

if that's the case, I see places like RPM want $600.00 for that service.

will update as this progresses.

cheers!

cpnwrench
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  #5  
Old 05-24-2019, 06:42 AM
ou18 ou18 is offline
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Quote:
Originally Posted by cpnwrench View Post


Well, I found problem.

ECU ( DME 7.2) fried.


took ECU out of car, pulled off back plate, and the stench unmistakable. Burnt Electronics.

continuity tests confirmed multiple grounds open in ECU that should be 0 ohms to case and pin 6 of X6003

found pedal sensor ground open, MAF ground open, multiple heated oxy sensor grounds open.

all those pins should be reading 0 ohms to case or pin 6.

new (USED) ECU/DME on way. hope i can just drop in ( after i do continuity test) and turn car on to test voltages outputs.

all I am reading telling me i have to get a replacement ECU re-programmed for my car.

Is this 100% true?

if that's the case, I see places like RPM want $600.00 for that service.

will update as this progresses.

cheers!

cpnwrench

I believe sounds correct.. I had read up on it a few times. The Vin has to be programmed to the ECU, but from what I have read there is also a rolling code in the ews. If the two dont match, you wont be able to start the car. Im not sure if you can do it yourself with some software or not.

Im not saying to use them, just did a quick google search, was the first thing that popped up. Just has a quick and dirty description of why it needs to be done.

https://www.ecudoctors.com/bmw-ecu-d...d-rebuilt.html

Again, maybe there is a way to do it yourself, I dont know. But might be one of those items thats worth having someone else do that specializes in the reprogramming..
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  #6  
Old 05-27-2019, 04:05 AM
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cpnwrench cpnwrench is offline
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Location: Texas now, workn G'vlle SC
 
Join Date: Oct 2008
Posts: 422
Mein Auto: 92 525i


Well, looks like i am getting this whole ECU thing sorted out.....

Got a used one from LQK same part number, came out of same year 740i

I tested the resistance for the exact same ground locations (pins) for the MAF, Heated OXYgen sensors, etc. on the replacement ECU and they all were as they should be versus OPEN like on MY ECU.

Now next step will be getting the ECU "CLONED".

will accomplish after the Memorial day holiday..

FWIW, to all those on forum who served, Thank YOU! for your service!

Company called PRECISIONECU (www.precisionecu.com) will copy info from my bad ECU onto the replacement one as long as i send a key, the EWS and both ECU's
They also said they would put latest FSB and updates to the ECU, so I may see some additional power improvements. ( one can only hope)

Total cost with shipping is $240.00

Have not tried to install the replacement ECU into the car as I don't think it would start without the programming. It might crank but probably wont run.

Hope this will do it.

I will post results here once I get everything back.........

cheers!

cpnwrench
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  #7  
Old 05-27-2019, 04:25 AM
ou18 ou18 is offline
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Quote:
Originally Posted by cpnwrench View Post
Have not tried to install the replacement ECU into the car as I don't think it would start without the programming. It might crank but probably wont run.cpnwrench

Wont work from what I understand. Due to the EWS and ECU need to communicate with each other properly. The rolling codes have to be in sync to let car start. Im sure I am completely over simplifying how it works and some electrical engineer on here can probably give an entire schematic with detailed write up on voltages and signal sine waves. But you get the idea.

Look forward to hearing how plug and play it is once you get it back with the recode completed...

Doesnt sound like to bad a price for all in...
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