2000 - 2999: 2305

2305-O2 SENSOR 1/1 SLOW RESPONSE





For a complete wiring diagram Consult Diagrams/Electrical.

Theory of Operation

The PCM monitors the exhaust gases for oxygen content and varies the rich/lean fuel mixture of the intake air fuel mixture to adjust the system. This diagnostic monitors the upstream O2 sensor circuit. The PCM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The PCM will turn off the MIL lamp diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
This diagnostic runs when the engine is running.

- Set Condition:
The PCM will illuminate the MIL lamp immediately when the diagnostic runs and fails.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview

Diagnostic Test

1. 02 1/1 HEATER CONTROL SUPPLY CIRCUIT OPEN




Disconnect the Oxygen sensor harness connector.
Remove the Engine control relay.

NOTE: Check connectors - Clean/repair as necessary, inspect for signs of Water intrusion in the connector.

Measure the resistance of the 02 1/1 HEATER CONTROL SUPPLY circuit between the O2 sensor harness connector and the Engine control relay connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 2

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. 02 1/1 HEATER CONTROL RETURN CIRCUIT OPEN




Measure the resistance of the 02 1/1 HEATER CONTROL RETURN circuit between the O2 sensor harness connector and the C2 PCM harness connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 3

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. 02 1/1 PUMP CURRENT CIRCUIT OPEN




Measure the resistance of the 02 1/1 pump current circuit between the O2 sensor harness connector and the C2 PCM harness connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 4

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. 02 1/1 RETURN CIRCUIT OPEN




Measure the resistance of the 02 1/1 return circuit between the O2 sensor harness connector and the C2 PCM harness connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 5

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. 02 1/1 PUMP CELL CURRENT TRIM CIRCUIT OPEN




Measure the resistance of the 02 1/1 pump cell current trim circuit between the O2 sensor harness connector and the C2 PCM harness connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 6

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. 02 1/1 SIGNAL CIRCUIT OPEN




Measure the resistance of the 02 1/1 signal circuit between the O2 sensor harness connector and the C2 PCM harness connector.
Is the resistance less than 10 Ohms?

Yes

- Go To 7

No

- Replace or repair the Wiring Harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. OXYGEN SENSOR




Measure resistance of the 02 sensor heater between the 02 HEATER CONTROL SUPPLY and 02 HEATER CONTROL RETURN circuits at the O2 sensor.
Is the resistance 3.2 +/- 0.8 ohms at ambient temperature?

Yes

- Replace the PCM.
- Replace and program the Powertrain Control Module Testing and Inspection
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace the sensor
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test