Codes 536 and 538, Key On Engine Running. What Could be the Cause?

[OVERKILL700HP]

This was on a 94 X in the Key on Engine Running position.
Codes 536 and 538.
What could be causing these codes?
All information helpful.
Thanks ahead.

 

[Runnin'OnEmpty]

Code 536 - BOO switch circuit failure or not activated during self-test.

Code 538 - Insufficient RPM change during Dynamic Response Test.

Most likely, these codes are because the brake pedal wasn't depressed, and the throttle wasn't advanced during the test.....

I'd say everything's OK, and you can ignore these codes, assuming there's no MIL/CEL lit.

 

[MrShorty]

As noted those codes are almost always a result of operator error during the KOER test. You likely missed pushing the brake pedal after engine id was output and missed the dynamic response test (aka goose test) just before the codes are output.

 

[OVERKILL700HP]

Thanks guys.
I appreciate it.