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.
1998 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE
Start Signal System Test
- Turn ignition switch to START position. Measure voltage between ground and appropriate PCM harness connector terminal. See START CIRCUIT WIRE COLOR & PCM TERMINAL IDENTIFICATION table for wire color. See Figure . Battery voltage should be present in START position only. Zero volts should be present in any other ignition switch position.
- If voltage is not as specified, check fuse No. 33 (7.5 amp) on I30, fuse No. 34 (15-amp) on Q45, in fuse box. If fuse is okay, repair circuit between PCM and fuse box. If voltage is as specified, check PCM terminals, harness, and harness connector terminals for damage or corrosion. Repair as necessary.
START CIRCUIT WIRE COLOR & PCM TERMINAL IDENTIFICATION
| Application | PCM Terminal No. (Wire Color) |
|---|---|
| I30 | 20 (Brown/White) |
| Q45 | 80 (Light Blue) |
Factory Service Tools
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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.
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