Topic: CEL List recently, weird codes

[DeepBlueGXP]

92k Miles.  Check Engine Light came on, reset and they returned in about 50 miles.  Thought is was the tune because U0303 seemed to be for a TCM for an Auto and since I have a manual, I figured it was a software burp, so I reloaded the tune.  No joy, 50 miles later and same codes.  Then I loaded an older tune, same thing.  Then I went back to stock to see if it was something to do with the tune.  Again, 50 miles later the codes popped.  I'll move the #1 to another position to see if I have a bad coil.  Any ideas?

P2188 Fuel Trim System Rich at Idle
P0300 General Misfire
P0301 Misfire Cylinder 1
U0303 Software Not compatible with transfer case module
BOFE? Unknown

[Sol Asylum]

A bad plug or coil could easily explain the first three codes.  That U0303 is odd, maybe a bad connector  .  Is BOFE a code you got?

[2kwk4u]

Just to be certain, have you tried pulling the codes with a different code scanner yet?

I remember when my Saturn VUE started throwing funky codes that made no sense (like auto trans codes - as it is a manual also).  It drove me nuts for months until I tried a different scanner.  All the while, it was truly only one code.  The gasked on my gas cap had gone bad.  New gas cap and a code reset took care of the problem when all was said and done.

[Arabas]

Any chance the battery is going bad and throwing random codes?

[miller11386]

I agree with SA

definitely move the coil and see what happens... maybe try fresh plugs if you haven't replaced them in a while? Check the wiring to the coils and see how it looks. maybe a bad loose connector is giving you grief.

[LatinVenom]

I would also try a different scanner as mentioned.

[DeepBlueGXP]

I pulled them with my Dashhawk.  Yes BOFE was a code too.

[scanner]

P0300 and P0301 need to be your targets. A good scantool will be able to read the freeze frame and failure record which will give the driving and EMS conditions at the time the DTC set.  That is if there is misfire on cylinder 1 at idle and P0300 set at the same or another e-rpm and ECT.

P2188 conditions are good to check too since it signals too rich at idle. Check for anything that can effect MAP & MAF data or fuel pressure.  If the idle is so rich that misfire starts you will get the package you describe.

U0303 is not needed on your vehicle so the scantool is suspect, this applies to the "BOFE" too.  There is no DTC with "O", assuming this is a simple typo consider this, all DTC are B,C,P or U followed by a 0,1,2,or 3 followed three digit hexadecimal number. So if we consider B0, B1, B2, or B3 with 0FE they too do not apply. 

How does the engine run? Start there and use the EMS parameteric data and DTCs with failure record data to diagnose.