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.
2004 Infiniti Q45FACTORY OEM SERVICE PROCEDURE
With GST
- Start engine and warm it up to normal operating temperature.
- Set voltmeter probes between ECM terminal 114 [HO2S1 (B1) signal] or 115 [HO2S1 (B2) signal] and ground. See Figure.
- Check the following with engine speed held at 2,000 RPM constant under no-load.
- The voltage should go above 0.70V at least once.
- The voltage should go below 0.21V at least once.
- If NG, go to Diagnostic Procedure .
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.