The QX4 is a midsize SUV manufactured by Nissan for its Infiniti luxury division. The QX4 was marketed during model years 1997 to 2003. When you turn on the vehicle, the "Check Engine" light should come on momentarily, then turn off after a few seconds. If the light doesn't turn off on its own, it could indicate there's a problem with your QX4's engine system. It is possible to reset the "Check Engine" light without taking your Infiniti QX4 to the repair shop.
Connect your Infiniti Qx4 to a second-generation onboard diagnostics, or OBDII, scanning tool to access the trouble codes stored within your vehicle's computer system. These trouble codes will be able to tell you -- or a repair shop -- exactly what is causing the Check Engine light to turn on. If you don't own an OBDII scanning tool, take your car to a auto parts retail chain like Auto Zone. Such stores will scan the trouble codes on your car for free.
Research the trouble codes that the scanning tool generates. Find them in your vehicle's manual or online. One helpful website is OBD-Codes.com. Some codes may suggest a malfunction with the "Check Engine" light. Others may point to a more serious problem that you should have addressed by a certified Infiniti repair shop. Do not attempt to reset the Check Engine light if the OBDII scanner generates this type of trouble code. Instead, take the SUV to an Infiniti-certified shop.
Follow the directions on your OBDII scanner to erase all the trouble codes from your car's system. This step will vary depending on the brand and model of your scanner. Employees at auto parts chain stores like AutoZone and Checkers may be able to assist with this step, or clear the codes from your car's system for you using an OBDII scanner. OBDII scanners typically have a function to turn off the instrument panel Check Engine light. Ask about this, or move to Step 4.
Disconnect your vehicle's battery to reset the Check Engine light. Leave it disconnected for 30 minutes.
Reconnect your vehicle to the battery. Turn the ignition on and see if the Check Engine light comes on as well. (You'll have to reset the clock and radio presets.)
Call a local Infiniti repair shop if the Check Engine light still comes on after you tried disconnecting the battery. A "Check Engine" light that won't turn off could indicate a serious problem with your engine that requires immediate attention.
