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 Circuit Tests
1) DO NOT perform any CIRCUIT TEST unless specifically instructed by a procedure under QUICK TEST or SWITCH MONITOR TEST. Ensure all non-EEC related faults are corrected. FOLLOW EACH TEST STEP, IN ORDER, UNTIL FAULT IS FOUND. When more than one code is received, start with the first code displayed.
2) CIRCUIT TESTS check electrical circuits to ensure they are okay before replacing sensors or any other components. Always test circuits for continuity between sensor and ECA. Test all circuits for short to power, opens or short to ground.
3) DO NOT connect any test light, or measure voltage or resistance at ECA unless specified in testing procedure. DO NOT pierce wiring. If backprobing is specified, always backprobe harness side of connector; DO NOT probe connector side.
4) Isolate both ends of circuit and turn ignition off whenever checking for shorts or continuity, unless specified otherwise. Disconnect solenoids and switches before checking circuit continuity or energizing solenoids.
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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.