Computed Timing Check

Turn ignition off. Connect timing light. Using jumper wire or test equipment, activate KOER SELF-TEST. If engine starts and stalls (or stalls during self-test), go to CIRCUIT TEST S. Start engine, and check for following:

• If Code 98 or 998 is displayed, EEC-IV system is operating in Failure Mode Effects Management (FMEM). Vehicle cannot be diagnosed in KOER SELF-TEST; rerun KOEO SELF-TEST.
• Check computed timing after last service code has been displayed. Timing will remain fixed for 2 minutes after last code has been retrieved unless self-test is deactivated.
• Computed timing, at crankshaft, should equal base timing (see vehicle emission decal) plus 20 degrees BTDC. This timing may vary 3 degrees (+/-). If computed timing is within specification, perform KOER SELF-TEST. If timing is not within specification, go to step 2) of CIRCUIT TEST PA (TFI), of CIRCUIT TEST PB (DIS) or of CIRCUIT TEST PC (EDIS).