Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code Output
Correct test results for system are dependent on the correct operation of several related non-EEC-IV components and systems. It may be necessary to correct faults in these areas before EEC-IV will pass QUICK TEST .
Verify that vehicle has been properly prepared. See PREPARATION and EQUIPMENT HOOK-UP under DIAGNOSTIC PROCEDURE . To start SELF-TEST, turn ignition on. DO NOT depress throttle during test. Observe and record all service codes.
- If engine does not start, go to CIRCUIT TEST A step 2). If KEY ON/ENGINE OFF code and continuous memory indicate code 11 (pass), go to TIMING CHECK .
- If any KEY ON/ENGINE OFF code is displayed with continuous memory code 11, KEY ON/ENGINE OFF SELF-TEST indicates a fault. Record codes and see TEST RESULTS & ACTION TO TAKE in this article.
- If any KEY ON/ENGINE OFF codes or any continuous memory codes are displayed indicates a fault. Record codes, but DO NOT repair continuous memory codes at this time. KEY ON/ENGINE OFF and ENGINE RUNNING SELF-TEST codes MUST be repaired first. See TEST RESULTS & ACTION TO TAKE in this article.
- If KEY ON/ENGINE OFF code 11 (pass), is displayed with ANY continuous memory code (except code 15), continuous memory indicates a fault. Record codes, but DO NOT repair continuous memory codes at this time. KEY ON/ENGINE OFF and ENGINE RUNNING SELF-TEST codes MUST be repaired first. Go to TIMING CHECK .
- If KEY ON/ENGINE OFF code 11 (pass), is displayed and continuous memory code 15 is displayed, go to CIRCUIT TEST NN , step 11). If NO CODES are displayed, repeat SELF-TEST and verify that no service codes are present. If no service codes present, go to CIRCUIT TEST NN , step 1).
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.