I have a '13 factory JCW. It threw 4 codes all at the same time as far as I can tell. (It's been a while since I read the codes and I've had the CEL on for some time. So they might not have occurred at the same time. Not sure.)

• 3490 MAP thermostat disconnect
• 2BC1 Mixture control rich
• 2D13 After cat 02 sensor resistance too high
• 277A MAF electrical fault.

It cuts out and runs at low power intermittently.

If I unplug the MAF the engine doesn't stall, which indicates a bad MAF, but live data shows air flow changing with engine speed. I'm not hooked to my car and I can't remember what that parameter is called, but it was the closest thing to live MAF data I could find. If that reading is coming from the MAF I'm getting conflicting data. Also, all the codes coming at once seems suspicious to me. I cleaned the MAF -- no change. Thoughts?

Thanks,

Mark

 

Replace the MAF sensor and then go from there.

 

That is my inclination. I just wanted to check around before throwing parts at it.

Mark

 

I think the result of your MAF sensor unplugging test was sufficient evidence to warrant replacing the sensor.

And if you're really lucky, the other codes will also be cleared.

 

Whelp, I put in a new Bosch MAF and nothing has changed. I cleared codes, took a drive, and they're all back. I had a hunch the MAF wasn't going to do it.

Now what? Smoke test?

Mark

 

https://bmwfault.codes/

 

Between the MAF sensor connector and DME, test the 4 MAF sensor wires for an open or short to ground.

Do the same for the 2 MAP thermostat wires.

Also verify that the wire colors in the circuit diagrams match your sensor wires. In some cases, it's possible to plug a connector into the wrong sensor.

 

Thanks, I'll give that a try. The MAF being good and these codes all happening at once would indicate a problem with wiring. If the wiring is good then it would be the DME I guess.

Mark

 

 

The white wire at the MAF tested as short to ground, and after testing the MAP wires (neither short to ground) and fiddling around, the white wire is no longer short to ground. I don't recognize the symbol for the white wire in the MAF, but it doesn't look like a ground.

I haven't tested anything for continuity because I need more info to find the right pins/sockets on the DME side of the harness. What's the best wiring diagram source? I don't want to get scammed. Know anything about this site? https://portal-diagnostov.com/en/router/?page_s=415003

Thanks,

Mark

 

 

 

MAP thermostat
X60231 pins
14 (black, ground for engine temperature sensor), 17 (orange, output 12V terminal 15), 32 (yellow, input for engine temperature sensor signal), 49 (white, input characteristic map thermostat signal)

MAF sensor
X60231 pins
9 (white, ground), 40 (blue, input intake air temp signal), 41 (orange, output 12V terminal 15)
X60232 pin
14 or 18? (yellow, hot-film air mass meter signal)

 

Thanks, this is what I need.

Mark

 

Good luck with the fix! Crossing my fingers for some bad sensor wires rather than a bad DME.

 

Whelp (and I don’t mean puppies),

All the wires test good — no open, no short to ground, and the two grounds are good. Looking like the DME.

Mark

 

Sorry to hear this outcome, but your results and conclusion are hard to refute.

 

Whelp! (And I don't mean puppies.)

I sent the DME out to be tested and it's bad. I STUPIDLY didn't take any pics before sending it so I don't have any of the numbers from the unit. The company still has it and wants $999 minus the $150 testing fee I already paid to clone to a donor. I'm tempted to get a donor and clone it myself with the software that's available in the hopes of saving some $$$ and to learn a thing or two. The dealer tells me the part number is 12148652746. That's all I know, but in doing research everyone uses the Bosch part # number or the unit version number to guarantee it'll work. How do I guarantee I get the correct donor? It's a '13 JCW, N18 with manual trans, comfort access, build date 10/2012. This number is listed for my car on RealOEM, as far as I can tell.

Thanks,

Mark

 

^Which number?

Verify the part # by entering your VIN here. Then navigate to ENGINE ELECTRICAL SYSTEM>CONTROL UNITS to look up the original and updated part #s.

Also ask the company in possession of your DME to send you pictures of your DME and labels?

 

This is the number the dealer gave me:12148652746. It’s in my post. I had also checked Realoem which shows the same number. So I guess that’ll do it, all the other numbers on the DME notwithstanding. In all the pics I’ve seen they don’t have the BMW part number.

mark

 

I sent it out and it tested bad ($149). They wanted a total of $999 (including the testing fee) to get a donor dme and clone it. I declined, and bought a donor for $175 and sent it to be cloned for $90. In my research I learned all about the various part numbers. I also found a lot of lousy information out there. Go figure. Fascinating…. Waiting for it to come back.

 

Given your available options, I likely would have done the same. Good luck!

 

Somehow I missed this message. It's enormously helpful. Thanks,

 

I installed the new (cloned used) DME and now it's throwing codes for no signal from the EGS transmitter (003BDD, 003BE1, 003BD8) which is for an automatic car. Mine is a manual. I understand you can get these codes if you have a DSC module from an automatic in a manual car, which I don't. What gives? Is the DME different too? Does it need to be coded for the type of transmission? The part numbers were listed as compatible.

Mark

 

Incorrect vehicle configuration data = re-code replacement DME for your 2013 JCW.