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.
1990 Isuzu Impulse AutomaticFACTORY OEM SERVICE PROCEDURE
Oxygen (O2) Sensor Test
- Start engine and warm to operating temperature. Ensure vehicle is operating in closed loop. Unplug O[I2] sensor connector at sensor.
- Using Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, connect DVOM (on voltmeter scale) between ground and oxygen sensor connector (sensor side).
- Place a short jumper wire in sensor lead (computer side). While holding jumper wire in one hand, alternately touch negative battery terminal and then positive terminal with other hand. DO NOT TOUCH sensor lead directly to battery.
- Monitor DVOM reading. When negative battery terminal is touched, oxygen sensor output voltage should increase (up to one volt). When positive battery terminal is touched, oxygen sensor output voltage should drop (as low as .1 volt). If oxygen sensor does not respond as indicated, replace sensor.
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.