'99 RR engine fault codes P0172 and P0175

[greghaugen]

Ok all;

Now that my previous problem is solved (thanks again), here is my next puzzler. A few months ago the "Service Engine Soon" light came on. Using RovacomLite I found the following fault codes:

THE MOTRONIC FAULT CODE MEMORY CONTAINS CODES FOR THE FOLLOWING CURRENT FAULTS -:

P0175 = MIXTURE ADAPTION FACTOR FRA BANK 2 DRIVE CYCLE C, WHICH HAS OCCURED 13 TIMES</B>
(SIGNAL TOO HIGH, THE FAULT IS CURRENTLY PRESENT, THIS FAULT CAUSES MIL LAMP ACTIVATION, THE FAULT HAS BEEN DETERMINED AS INTERMITTENT).

P0172 = MIXTURE ADAPTION FACTOR FRA BANK 1 DRIVE CYCLE C, WHICH HAS OCCURED 17 TIMES</B>
(SIGNAL TOO HIGH, THE FAULT IS CURRENTLY PRESENT, THIS FAULT CAUSES MIL LAMP ACTIVATION, THE FAULT HAS BEEN DETERMINED AS INTERMITTENT).



When I check these in the shop manual it seems that the fuelling is intermittently too rich causing the system to have to go full lean which causes the above errors. Being that there were no other faults such as oxygen sensors, etc, I tried to logically deduce what would cause the system to receive too much fuel and have to compensate by going full lean and the only thing I could think of was that the purge valve on the EVAPS system was faulty and would dump the fuel vapor load into the combustion system inappropriately. This is a 4.0 with the Bosch system and the advanced EVAPS.

BTW, I cleared the codes once, had the light come back on in a few days with the same errors, tried clearing a second time but the light wouldn't go off, and just now successfully cleared them again and the light is still off after a 15 minute drive.

Thanks;

Greg

[theberke]

did you ever find out about the codes?

David
Los Angeles, CA
99 P38 - Bosch

[Emmanuel]

Hi, I have a 2000 Ford Explorer XLS and it currently displaying codes P1309, Misfire Monitor AICE Chip Fault, P0172, System too Rich (Bank 1) and P0175, System too Rich (Bank 2). I tried disconnecting the battery and all these codes came back. Do you think these issues are related? I was thinking it's a Mass Air Flow Sensor. Any thoughts?
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[Les Parker]

Not sure about the Explorer info.
Could be you are not on the correct web site !

Best of luck in your quest for data.