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
Feedback System
- Start engine, and warm it to operating temperature. Ensure idle speed and timing are adjusted to specification. Increase engine speed to about 2000 RPM for 2 minutes under no-load condition. Using a small screwdriver, turn diagnostic mode selector screw on ECM.
- With mode selector screw turned fully clockwise for at least 2 seconds, inspection lights will begin to flash. Turn screw fully counterclockwise. This switches ECM to Mode II, which is used to monitor exhaust gas sensor feedback signals.
- With engine speed at 2000 RPM for 2 minutes, LED should flash at least 5 times during a 10-second period. If sensor does not respond as indicated and no other faults which may affect air/fuel mixture are indicated by ECM self-diagnostic system, use a voltmeter to verify input signals to ECM are correct. If input signals are correct, replace oxygen sensor. If input signals are not correct, replace ECM.
- J30 and Q45 use 2 oxygen sensors. When Mode II is first entered, left bank oxygen sensor is being monitored. To change to right bank monitoring (with engine running), turn diagnostic mode selector screw on ECM fully clockwise. Wait at least 2 seconds. Turn selector lever fully counterclockwise. Repeat step 2).
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.