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.
Test QD: Step 1
1) Codes 71 or 72: Check For Electrical Noise Sources Continuous Memory Code 72 indicates that power to the ECA was interrupted sometime during the last 40 warm-up cycle. A Continuous Code 71 indicates that sometime during the past 40 warm-up cycles, the ECA software requested a re-initialization or review of previous drive sequence data. This process could result in a driveability complaint. Possible causes for this fault or complaint are:
- Vehicle power interrupted to ECA
- Spark plug wires incorrectly routed too close to ignition
- High tension wire shielding removed
- Electrical, radio, or motor static noise
- Test Pin No. 20 (case ground) not grounded to chassis
- Open diodes on A/C or ISC relay
Turn key off. Ensure that EEC-IV wiring and components are more than 2" (50 mm) away from secondary ignition wires and ignition coil. Make sure that EEC-IV wiring and components are more than 4" (100 mm) away from distributor, ignition coil, and starter motor and its wiring. If these items are correct, go to next step. If not, correct as necessary and repeat QUICK TEST.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.