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.
How To Use The Diagnostic Chart And Inspection Procedure
- CONNECTOR CONNECTION AND TERMINAL INSPECTION
- For troubleshooting, diagnostic trouble code (DTC) charts or problem symptom table are provided for each circuit with detailed inspection procedures in this article.
- When component parts, wire harnesses and connectors of each circuit are found to be normal in troubleshooting, the problem is most likely in the ECU. Accordingly, if diagnosis is performed without the problem symptoms occurring, refer to Step 8 to replace the ECU. Always confirm that the problem symptoms are occurring, or proceed with inspection while using the symptom simulation method.
- The instructions "Check wire harness and connector" and "Check and replace ECU" which appear in the inspection procedure are common and applicable to all DTCs. Follow the procedure outlined below whenever these instructions appear.
OPEN CIRCUIT:
An open circuit the result of a disconnected wire harness, a faulty contact in the connector, a connector terminal pulled out, etc.
NOTE:- A wire is rarely broken in its middle. Most problem occur at the wire ends. Carefully check the connectors of sensors and actuators.
- Faulty contacts could be due to the rusting, contamination, and/or deformation of connector terminals. In some cases: 1) simply disconnecting and reconnecting the connectors will fix the problem, or 2) even though no abnormality is found in the wire harness or connector, the problem disappears after the check (meaning the cause was most likely in the wire harness or connectors).
SHORT CIRCUIT:
A short circuit could be the result of contact between the wire harness and the body ground or a short circuits switch.
NOTE: When there is a short circuit between the wire harness and body ground, check thoroughly it wire harness is caught in the body or is clamped properly. - CONNECTOR HANDLING
When inserting tester probes into a connector, insert them from the rear of the connector. When necessary, use mini test leads. For water resistant connectors which cannot be accessed from behind, take good care not to deform the connector terminals.
- CONTINUITY CHECK (OPEN CIRCUIT CHECK)
- Disconnect the connectors at both ECU and sensor sides.
- Measure the resistance between the applicable terminals of the connectors.
Resistance: 1 Ω or less
NOTE: Measure the resistance while lightly shaking the wire harness vertically and horizontally.
NO RELATED
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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.