2003 R53, 240,000mi., simultaneously displayed codes PO340, PO445, PO037, and PO031. The last maintenance on that car was a water temp sensor and thermostat, but at least a thousand miles before the light came on. Can anyone help me troubleshoot this? The only step I can think of right now is to do resistance tests on each component. However, I'm stumped that all of them triggered simultaneously. Is there another component in common, like a fuse?

 

You have crankshaft position sensor (CPS), evap leak, and O2 sensor fault codes none of which should have been activated by your most recent maintenance. The CPS is the most labor-intensive repair. Evap leak could be the purge valve which is easy to replace or that code could also simply be the need for a new fuel cap that's not sealing properly. I would start with the CPS then the purge valve and retest your OBD II codes between replaced components. Honestly, with a quarter-million miles I'm surprised this is all you need to address.

 

Yeah I understand what you're saying. My question is more about the likelihood that all of these components failed simultaneously. I don't want to throw parts before confirming the cause. I've replaced my 02 sensors and purge valve within the last 20,000 miles or so and wheel speed sensors probably within the last 20 or 25,000. How can I check each component before replacing them?

 

I would clear the codes and test drive it and see if they all reset. A good manual that will help you trouble shoot each code is Mini Cooper Diagnosis Without Guesswork by Bentley Publishers. Ista D or ISTA + will read the codes, tell you whether they are active and give you a test plan to help diagnose them. Just my 2 cents.

 

how does the engine run, besides the codes?

 

Thanks for the advice! I’ll check the wiring and fuses.

 

Thanks. I'll look for that. I do have a decent code reader, which is helpful.

I replaced the camshaft sensor and that solved the hard start (it would take a two cycles of the key, always). I reset the codes and all four came back as soon as I started the car. It runs fine except for needing to turn over just a bit longer than it used to before starting.

 

Check fuse F03 as it supplies 12 volts to all those components

 

Interesting. Today I discovered clogged sunroof drains and water running down the A pillar onto the floor. I'll take a look tomorrow.

 

I already cleaned the bcm and the gauges connection and the connection on the fuse box need help I have the same problem can someone send me a link off video fixing it and I’m from Philippines mini cooper parts are hard to find

 

Turned out to be the fuse. Thanks!

 

which fuse? might help someone in the future

 

F03, which is under the hood and labeled on the fuse box cover.