KOER codes need help
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KOER codes need help
<TABLE><TBODY><TR><TD vAlign=top width="100%">91 explorer eb
KOEO codes are clear, I actually cleared them last week while trying to diagnose this overdrive problem.
KOER codes 21 77 74
I need a little help with these codes. All the code sheets i have say there should be 3 digit codes not 2 digit codes. Whats up with that??
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KOEO codes are clear, I actually cleared them last week while trying to diagnose this overdrive problem.
KOER codes 21 77 74
I need a little help with these codes. All the code sheets i have say there should be 3 digit codes not 2 digit codes. Whats up with that??
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Joined: Dec 2001
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From: UT
Your '91 is the only year 4.0 that outputs 2 digit codes. I don't know whose code sheets you're using, but there are a lot of code lists out there (especially on the internet) that don't know which applications output which type of code.
KOER 21 is usually from performing the KOER test on a cold engine. The computer expects the ECT output to be above a certain point (probably something like 180 F) during the KOER test. If it's cold, you can get a KOER 21
KOER 77 and 74 are almost always operator error. I don't know whose instructions you are using, but it seems there are a lot of KOER instructions out there that don't fully explain the test protocol. Just after engine id is output, you need to press on the brake to actuate the BOO switch, which almost always resolves the 74. Later in the test, when the "goose pulse" is given, you need to "goose" the throttle to resolve the 77.
Check those items and repeat the KOER test.
KOER 21 is usually from performing the KOER test on a cold engine. The computer expects the ECT output to be above a certain point (probably something like 180 F) during the KOER test. If it's cold, you can get a KOER 21
KOER 77 and 74 are almost always operator error. I don't know whose instructions you are using, but it seems there are a lot of KOER instructions out there that don't fully explain the test protocol. Just after engine id is output, you need to press on the brake to actuate the BOO switch, which almost always resolves the 74. Later in the test, when the "goose pulse" is given, you need to "goose" the throttle to resolve the 77.
Check those items and repeat the KOER test.
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