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.
1993 Infiniti G20 AutomaticFACTORY OEM SERVICE PROCEDURE
System Test
- Start engine, and warm to operating temperature. Check Idle speed. If idle speed is excessive, disconnect IACV-AAC valve harness connector, idle speed should drop. If idle speed does not drop, check for battery voltage at IACV-AAC connector terminal "A" (Gray wire on G20, Green/Yellow wire on J30, Red wire on Q45). If battery voltage is present, go to next step. If battery voltage is not present, check fuses and harness for open circuit.
- Turn ignition off. Disconnect ECM harness Connector. Check harness continuity between IACV-AAC connector terminal "B" (Light Blue wire on G20, Blue wire on J30, Brown/White wire on Q45) and ECM. (Terminal 113 on G20, terminal 4 on J30 or terminal 111 on Q45). Continuity should exist. If continuity does not exist, repair wire as necessary.
- If harness tests okay, test IACV-AAC valve and inspect ECM connector terminal pins.
NOTE:
On Q45, see ADJUSTMENTS
article in the ENGINE PERFORMANCE Section for testing and adjustment of fast idle cam.
IDLE SPEED SYSTEM INPUT SIGNALS
| Application | Model Usage | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| A/C Clutch Signal | G20, (1) J30 & (1) Q45 | ||||||||
| Mass Airflow Sensor | Q45 | ||||||||
| Battery Voltage | G20, J30 & Q45 | ||||||||
| Crankshaft Position Sensor | G20, J30 & Q45 | ||||||||
| Engine (Coolant) Temperature | G20, J30 & Q45 | ||||||||
| Ignition (START) Signal | G20, J30 & Q45 | ||||||||
| Neutral Switch | (2) G20 | ||||||||
| Park/Neutral (Inhibitor) Switch | G20, (3) J30 & (4) Q45 | ||||||||
| Power Steering Pressure Switch | G20, J30 & Q45 | ||||||||
| Throttle Position Sensor | G20, J30 & Q45 | ||||||||
| Closed Throttle Position Switch | J30 & Q45 | ||||||||
| Vehicle Speed Sensor | G20, J30 & (3) Q45 | ||||||||
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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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