Grand Cherokee
NOTE:
For circuit identification and wiring diagram, see WIRING DIAGRAMS article. After each repair procedure has been completed, reconnect all components. Perform TEST VER-5
under VERIFICATION TESTS to ensure system is functioning properly.
- Turn ignition on, with engine off. Using scan tool, actuate HO2S HEATER TEST. Wait 2 minutes for HO2S voltages to stabilize. Using scan tool, read HO2S signal voltage. If voltage is one volt or less on all HO2S, stop actuation test. No problem is indicated at this time. Test is complete. If voltage is more than one volt at any HO2S, stop actuation test and go to next step.
- Turn ignition off. Disconnect suspect HO2S connector that has voltage of more than one volt. See HEATED OXYGEN SENSOR LOCATION (GRAND CHEROKEE) table. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, using scan tool actuate HO2S HEATER TEST. Measure voltage between ground and power input circuit at suspect HO2S connector. See IDENTIFYING POWER INPUT CIRCUIT TO HO2S HEATER (GRAND CHEROKEE) table. If voltage is more than 10 volts, stop actuation test and go to next step. If voltage is 10 volts or less, repair open in power input circuit to HO2S. See WIRING DIAGRAMS article.
- Measure resistance between ground and Black wire at suspect HO2S connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in HO2S heater ground circuit (Black wire).
- At this time, suspected HO2S heater is assumed to be defective. Replace HO2S.
HEATED OXYGEN SENSOR LOCATION (GRAND CHEROKEE)
| Application | Location | ||
|---|---|---|---|
| 1/1 HO2S | |||
| Calif. | |||
| 4.0L | In Front Exhaust Manifold | ||
| 4.7L | In Driver's Side Exhaust Downpipe, In Front Of Catalytic Converter | ||
| Federal | In Exhaust Downpipe, In Front Of Catalytic Converter | ||
| 1/2 HO2S | |||
| Calif. | |||
| 4.0L | In Front Exhaust Pipe, Below Front Mini-Catalytic Converter | ||
| 4.7L | In Exhaust Pipe, Behind Left Catalytic Converter | ||
| Federal | In Exhaust Downpipe, Behind Catalytic Converter | ||
| 2/1 HO2S | |||
| Calif. | |||
| 4.0L | In Rear Exhaust Manifold | ||
| 4.7L | Passenger's Side Exhaust Downpipe, In Front Of Catalytic Converter | ||
| 2/2 HO2S | |||
| Calif. | |||
| 4.0L | In Rear Exhaust Pipe, Below Front Mini-Catalytic Converter | ||
| 4.7L | In Exhaust Pipe, Behind Passenger's Side Catalytic Converter | ||
IDENTIFYING POWER INPUT CIRCUIT TO HO2S HEATER (GRAND CHEROKEE)
| Application | Wire Color | |
|---|---|---|
| 1/1 HO2S | ||
| Calif Models | Violet/White | |
| Federal Models | Orange/Dark Green | |
| 1/2 HO2S | ||
| Calif Models | Violet/Orange | |
| Federal Models | Orange/Dark Green | |
| 2/1 HO2S | ||
| Calif Models | Violet/White | |
| 2/2 HO2S | ||
| Calif Models | Violet/Orange | |