Step 4.0 Computed Timing Check: Begin

Turn key OFF and wait 10 seconds. Activate self-test procedure (same as previous):

VOM: Jumper Self-Test Input (STI) single terminal pigtail to SIG RTN terminal at the Self-Test connector. See Figure.
STAR Tester: Latch the center button in the down position.
"Check Engine" or "Service Engine Soon" Light (MIL): Jumper Self-Test Input (STI) single terminal pigtail to SIG RTN terminal at the Self-Test connector. See Figure. Service Codes will be flashed on the Light.
Scan Tool: As described by scan tool manufacturer.

Start engine. The Engine Running (KOER) test will begin. Ignore all codes (ID Code, Dynamic Response Code, etc.) except for Code 98.

NOTE: If engine starts but stalls, or stalls during self-test, go to TEST S - SYSTEM CHECK , step 1).

NOTE: If KOER Code 98 is displayed, it indicates EEC-IV system is operating in Failure Mode Effects Management (FMEM) and DID NOT PASS KOEO On-Demand/Continuous Memory Self-Test. The Computed Timing Check cannot be performed accurately while in FMEM. Go back and repeat STEP 3.0: PERFORM KOEO SELF-TEST .

Check computed timing after the last code has been displayed. The timing will remain fixed for 2 minutes after the last code has been displayed, unless self-test is deactivated before then.

Computed timing, at the crankshaft, should equal the base timing (see vehicle emission decal) plus 20 degrees BTDC. This timing may vary 3 degrees (+/-).

Is computed timing is within specifications?:

Yes: Go to STEP 5.0: PERFORM ENGINE RUNNING (KOER) SELF-TEST
No: Go to TEST P - SPARK TIMING CHECK , step 2).