LEMON Manuals: Even more car manuals for everyone
Home >> Jeep >> 2000 >> Cherokee Classic, 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self Diagnostics >> Diagnostic Tests >> DTC P0155: 2/1 O2 Sensor Heater Failure (4.0L With CALIF. Emissions) >> Testing

DTC P0155: 2/1 O2 Sensor Heater Failure (4.0L With CALIF. Emissions): Testing

NOTE: 2/1 HO2S is located in rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.
  1. Turn ignition on. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is displayed and displayed count is "0", go to next step. If DTC SPECIFIC GOOD TRIP counter is not displayed or displayed count is not "0", go to step  6 .
  2. Turn ignition off. Disconnect 2/1 HO2S connector. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Dark Green wire at 2/1 HO2S connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in power circuit to 2/1 HO2S heater. See WIRING DIAGRAMS article.
  3. Turn ignition off. Measure resistance between chassis ground and Black wire at 2/1 HO2S connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire between 2/1 HO2S and ground. See WIRING DIAGRAMS article.
  4. Measure resistance between Dark Green wire and Black wire at 2/1 HO2S connector (component side). If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, replace 2/1 HO2S.
  5. At this time, PCM is assumed to be defective. Replace PCM.
  6. It is assumed that there is an intermittent problem with wiring harness and/or connectors. Visually inspect all related connectors and wiring harness for any possible problems. Also, check for any related technical service bulletins.
scientia non olet · About LEMON Manuals