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Need some code help


Well-Known Member
April 30, 2006
Reaction score
City, State
Lawrence, Kansas
Year, Model & Trim Level
94 Explorer Sport
OK, so I had to try out my new scanner!!!!

These are all KOEO codes:
124 TPS high
172 lean bank 1
173 rich bank 1
176 lean bank 2
542 fuel pump secondary circuit failure
I think the last one is in continous memory.
I cleared the codes and got a a code
But I still get this code 542, How do I clear the continous memory again?

I think the first thing to do is figure out how the scanner is distinguishing between KOEO and CM codes. I've never used a scanner; I'm only familiar with the "poor man's" method (see my notes on pulling EEC-IV codes thread). 172, 173 and 176 all have to be CM codes (or KOER codes, but it doesn't look like you've tried the KOER test), because the O2 sensor(s) can't be tested with the engine off. My code list suggests that a 124 also has to be a CM code. 542 can be either a KOEO code or a CM code or both. This suggests to me that the 542 you are seeing is actually a KOEO code. KOEO codes, as hard faults, aren't stored in memory, nor can they be "cleared," except by repairing the fault that is triggering them.

So, the first thing to do would be to get a feel for how the scanner distinguishes between KOEO and CM codes (some scanners output a code 10 for the separator pulse) so you can positively tell which is which.
Then, if I've correctly deduced the scenario, figure out the cause of the KOEO 542.