2
- Start the engine.
- Allow the engine to reach operating temperature. Refer to Scan Tool Data List .
- Operate the engine at 1,500 RPM for 30 seconds.
- Observe the HO2S 1 voltage parameter with a scan tool.
- Is the HO2S 1 voltage parameter varying above and below the specified range? 300-600 mV
Yes: Go to Step 3
No: Go to Step 4
3
- Observe the Freeze Frame/Failure Records for this DTC.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- Did the DTC fail this ignition?
--
Yes: Go to Step 4
No: Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
4
- Turn OFF the ignition.
- Disconnect the heated oxygen sensor (HO2S) 1.
- Turn ON the ignition, with the engine OFF.
- Observe the HO2S 1 voltage parameter with a scan tool.
- Is the HO2S 1 voltage parameter less than the specified value? 100 mV
Yes: Go to Step 6
No: Go to Step 5
5
- Is the HO2S 1 voltage parameter more than the specified value? 800 mV
Yes: Go to Step 7
No: Go to Step 9
6
- Test the HO2S 1 high signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 8
7
Important: The sensor may be damaged if the circuit is shorted to a voltage source.
- Test the HO2S 1 high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 16
8
- Test the HO2S 1 high signal circuit for a short to the HO2S low signal circuit or to the HO2S heater low control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 16
9
- Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 1 harness connector on the engine harness side and a good ground.
- Observe the HO2S 1 voltage parameter with a scan tool.
- Is the HO2S 1 voltage parameter less than the specified value? 100 mV
Yes: Go to Step 10
No: Go to Step 12
10
- Remove the jumper wire from the previous step.
- Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 1 harness connector on the engine harness side and the low signal circuit of the HO2S 1 harness connector on the engine harness side.
- Observe the HO2S 1 voltage parameter with a scan tool.
- Is the HO2S 1 voltage parameter less than the specified value? 100 mV
Yes: Go to Step 13
No: Go to Step 11
11
- Test the HO2S 1 low signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 14
12
- Test the HO2S 1 high signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 14
13
- Test for an intermittent and for a poor connection at the HO2S 1. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 15
14
- Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
- Did you find and correct the condition?
--
Yes: Go to Step 17
No: Go to Step 16
15
Notice: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in the Preface section.
Important: The HO2S may be damaged due to contamination. Prior to replacing the HO2S inspect for the following sources of contamination:
• A silicon contaminated HO2S
• Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
• Engine oil consumption--Refer to Oil Consumption Diagnosis in Engine Mechanical.
• Engine coolant consumption--Refer to Loss of Coolant in Engine Cooling.
- Replace the HO2S 1. Refer to Heated Oxygen Sensor 1 Replacement .
- Did you complete the replacement?
--
Yes: Go to Step 17
--
16
- Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
- Did you complete the replacement?
--
Yes: Go to Step 17
--
17
- Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- Did the DTC fail this ignition?
--
Yes: Go to Step 2
No: Go to Step 18
18
- Observe the Capture Info with a scan tool.
- Are there any DTCs that have not been diagnosed?
--
Yes: Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information
No: System OK