Diagnostic Aids

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware that following non-EEC related areas may be cause of problem:

• Technician testing EEC system did not perform brief Wide Open Throttle (WOT) after Dynamic Response Code.
• Mechanical engine components are faulty.
• Engine did not go more than 2000 RPM during WOT.

This test is only intended to diagnose:

• Throttle movement (minimum 3/4 throttle).
• RPM increase is greater than 2000 RPM.

If throttle is snapped open briefly, WOT test may not be passed. Ensure throttle is depressed fully to WOT and engine speed exceeds 2000 RPM.

1)  Code 77/538 Displayed: System Failed To Recognize WOT Test - Rerun KOER SELF-TEST as follows.

• Start engine.
• Activate KOER SELF-TEST.
• Observe ID Code 2 (Code 0 with STAR tester).
• Observe Dynamic Response Code 1 (Code 0 with STAR tester).
• Perform brief WOT.
• Testing is complete; KOER code output begins.

If Code 77/538 is still displayed and engine speed was more than 2000 RPM, replace ECA and rerun QUICK TEST  . If engine speed was not more than 2000 RPM, check throttle for binding and repair as necessary. If Code 77/538 is no longer present, vehicle has passed dynamic response test. Service other codes as necessary.