P2273-O2 SENSOR 2/2 SIGNAL STUCK RICH
P2273-O2 SENSOR 2/2 SIGNAL STUCK RICH
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For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The downstream O2 Sensor is located in the exhaust path behind the Catalytic Converter, is monitored for proper response to assure optimum Catalytic Converter efficiency. The downstream O2 Sensor response monitor is intended to diagnose a downstream O2 Sensor that is not moving or stuck in a voltage window and to insure accurate information for catalyst monitor diagnosis.
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When Monitored:
With the engine running, vehicle speed above 96 kph (60 mph), throttle open for a minimum of 120 seconds, ECT greater than 70°C (158°F), Catalytic Converter temperature greater than 600°C (1112°F) and downstream Oxygen Sensor in a rich state. During a decel fuel shutoff event, the downstream Oxygen Sensor should switch from rich to lean within a specific time.
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Set Condition:
The Powertrain Control Module (PCM) monitors the downstream O2 Sensor. If the PCM does not detect a rich to lean switch within a specific time during a decel fuel shutoff event, the monitor will fail. Two trip fault. Three good trips to turn off the MIL.
Possible Causes |
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| OXYGEN SENSOR WIRING OR CONNECTORS |
| (K243) O2 SENSOR 2/2 SIGNAL CIRCUIT |
| (K904) O2 SENSOR 2/2 RETURN CIRCUIT |
| O2 SENSOR 2/2 |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
1. DIAGNOSTIC TROUBLE CODE (DTC) IS ACTIVE
| 1. | Start the engine and allow it to reach operating temperature. |
When the engine is operating, do
not stand in direct line with the fan. Do not put your hands near
the pulleys, belts or fan. Do not wear loose clothing. Failure to
follow these instructions may result in possible serious or fatal
injury.
WARNING:
| NOTE: | It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set. |
| 2. | With the scan tool, read the active DTCs. |
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
2. CHECKING THE OXYGEN SENSOR OPERATION
| NOTE: | Check for signs of contaminants that may have damaged the O2 Sensor, such as contaminated fuel, unapproved silicone, oil and coolant. |
| 1. | Perform the diagnostic procedure for CHECKING THE OXYGEN SENSOR OPERATION. (Refer to 29 - Non-DTC Diagnostics/Drivability - Gas - Diagnosis and Testing) . |
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Go To 3
3. POWERTRAIN CONTROL MODULE (PCM)
| 1. | Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 Sensor 2/2 and the Powertrain Control Module (PCM). |
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. (Refer to 08 - Electrical/8E - Electronic Control Modules/MODULE, Powertrain Control - Removal) .
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).