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So I've had an intermittent CEL for about 2 weeks and I just pulled the codes and the KOER codes left me scratching my head and I'm looking for where to go with it.
Truck is a 97 F250HD with 351/5sp
KOEO results:
13 RPM Unable to reach lower limit self test
33 EGR Valve position sensor Circuit
KOER
17 RPM Below Self test limit, set too low
25 knock sensor not detected during testing
38 Idle track switch circuit open
The truck has 130k on it and I could see possibly the EGR given that it'll sputter once in a great while and the CEL only seems to come on when running the a/c or hvac. Any direction is appreciated! Thanks!
If they are 3-digit codes, I'm guessing the KOER codes were
172 - Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S
and
538 - System did not receive "goose" test.
This confused me with my '88... I thought it would be 2-digit codes but they were 3-digit codes. I'm not sure what determines which kind of codes a truck has.
So if I have an '88 with a ZF5 and am getting 3-digit codes, someone probably replaced the computer at some point?
Would say so.
You need to check the drawing number on it.
Its the big number that starts with something like E8 or F3. It would start with a E or an F.
You should be able to see the number without taking it out.
Yeah truck is obd 1 and its a manual tranny. I used a code reader to get it and the way it pulsed out seemed to be for 2the digit codes. Ill run it again to make sure.
Well 538 is operator error so we will forget that one.
172 is a CM code and it says that the system indicates lean.
This would be your MIL flashing in the cluster.
Possible causes: