Test NTC-8A - Checking Oxygen Sensor (O2S) Heater
WARNING: This page is about a different car, the 1995 Jeep Wrangler, 1995 Jeep Grand Cherokee, and 1995 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform TEST NTC-1A
before proceeding with this test. For connector terminal identification, see CONNECTOR IDENTIFICATION
at beginning of article. For wiring diagrams, see WIRING DIAGRAMS
at the end of this article. Perform TEST VER-2A
after each repair.
- Turn ignition on. Using scan tool, actuate Automatic Shutdown (ASD) fuel system actuator test. Wait at least 2 minutes for O2S voltage to stabilize. Using scan tool, read O2S sensor voltage. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, O2S is okay and test is complete.
- Disconnect O2S 4-pin connector and ensure connector is clean and not damaged. With ASD fuel system actuator test still running and scan tool in voltmeter mode, check voltage at O2S 4-pin connector terminal No. 4, fused ignition switch output, (Dark Green/White wire on XJ body, Dark Green/Orange wire on YJ body, or Orange/Dark Blue wire on ZJ body). If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in fused ignition switch output circuit between O2S 4-pin connector terminal No. 4 and splice.
- Using scan tool stop ASD fuel system actuator test. Using scan tool in ohmmeter mode, check resistance O2S 4-pin connector terminal No. 3, heater ground, (Black/Tan wire on XJ and ZJ or Black wire on YJ). If resistance is more than 5 ohms, repair open in heater ground circuit. If resistance is less than 5 ohms, replace O2S.