Test Pin Identification

The purpose of the Octane Adjust Shorting Bar is to provide optimum spark advance for the fuel used. If vehicle engine detonates (spark knock), remove Octane Shorting Bar. This retards spark advance about 3 to 4 degrees. If vehicle continues to detonate, use fuel with a higher octane rating.

1) Code 57/341: Inspect Octane Adjust In-Line Connector  Code 57/431 indicates Octane Adjust Shorting Bar is not in, or OCT ADJ circuit is open. Turn ignition off and wait 10 seconds. Inspect Octane Adjust in-line connector. If shorting bar has been removed, return to QUICK TEST for complete diagnosis. If shorting bar is in place, go to next step.

2) Check Octane Adjust Circuit Continuity  There should be continuity from OCT ADJ circuit, through in-line connector and shorting bar, to SIG RTN circuit. Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector; inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 46 and OCT ADJ test pin at breakout box. If resistance is less than 5 ohms, replace ECA. Remove breakout box and rerun QUICK TEST. If resistance is greater than 5 ohms, repair open OCT ADJ circuit, shorting bar or SIG RTN circuit. Remove breakout box and rerun QUICK TEST.

3) Check For Code 11  Start engine and let idle at operating temperature. Turn ignition off and wait 10 seconds. Enter KOEO SELF-TEST. If Code 11 or 111 is present, go to next step. If Code 11 or 111 is not present, use higher octane fuel or check for other possible causes for Code 57/341; for all other codes, return to QUICK TEST.

4) Verify In-Line Shorting Bar Is Installed  Turn ignition off and wait 10 seconds. Inspect Octane Adjust in-line connector. If shorting bar is installed, go to next step. If shorting bar is not installed, go to step 7).

5) Verify Drive Concern  Turn ignition off and wait 10 seconds. Locate and remove shorting bar. Test drive vehicle to verify complaint. If symptom is present, go to next step. If symptom is not present, EEC is okay; testing is complete.

6) Rerun KOEO SELF-TEST  Verify engine is at normal operating temperature. Turn ignition off and wait 10 seconds. Enter KOEO SELF-TEST. If Code 57 or 341 is present, use higher octane fuel; testing is complete. If Code 57 or 341 is not present, go to next step.

7) Check Octane Adjust Circuit For Short To Ground  Turn ignition off and wait 10 seconds. Install breakout box and leave ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between OCT ADJ circuit at in-line connector and test pins No. 40 and 60 at breakout box.

If resistance is less than 10 k/ohms, repair short circuit; remove breakout box and rerun QUICK TEST. If each resistance is greater than 10 k/ohms, use higher octane fuel. If fuel is okay, replace ECA, remove breakout box and rerun QUICK TEST.