For 1990-2009 cars
Engine Controls Components
Heated Oxygen Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. If the average response time is too slow, a DTC will set.

A lean to rich transition is determined when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean transition is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is most likely defective and should be replaced.

### Conditions for Setting the DTC

• | DTCs P0100, P0107, P0108, P0116, P0117, P0118, P0131, P0132, P0134, P0135, P0171, P0172, P0174, P0175, P0410, P1114, P1115, P1133, not set.

• | Fuel system operating in Closed Loop.

• | Engine speed between 1000 RPM and 1700 RPM.

• | Engine Air Flow between 12 grams per second and 28 grams per second.

• | EVAP Canister purge duty cycle less than 100%.

• | Lean to rich (Below 300 mV to above 600 mV) response average time is greater than 110 Milliseconds or 150 milliseconds if the vehicle is equipped with an L99 engine.

• | Rich to lean (Above 600 mV to below 300 mV) response average time is greater than 110 Milliseconds or 150 milliseconds if the vehicle is equipped with an L99 engine.

• | Above conditions are met for 100 seconds

### Action Taken When the DTC Sets

• | The PCM will illuminate the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.

• | The PCM will record operating conditions at the time the diagnostic fails. The first time the diagnostic fails, this information will be stored in Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the operating conditions at the time of failure will be written to Freeze Frame and the Failure record will be updated.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

• | A last test failed (Current DTC) will clear when the ignition is cycled and the diagnostic runs and does not fail.

• | A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• | PCM battery voltage is interrupted.

• | Using a Scan tool.

### Diagnostic Aids

• | A malfunction in the HO2S heater circuits will cause a DTC to set. Check HO2S heater circuits for intermittent opens/connections.

• | An oxygen supply inside the HO2S is necessary for proper operation. This supply of oxygen is provided through the HO2S wires. All HO2S wires and connections should be inspected for breaks or contamination. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5).

• | Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed. For intermittents, refer to Symptoms .

### Test Description

Number(s) below refer to step numbers on the diagnostic table.

1. Determines if the fault is present. This test may take 5 minutes for the diagnostic to run. For any test that requires probing the PCM or a component harness connector, must use the Connector Test Adapter Kit J 35616-A. Using this kit will prevent damage to the harness connector terminals.

2. When DTCs P0133 and P0153 are set at the same time, is good indication that a fuel contamination problem is present.

3. An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.

4. Checks whether a good ground circuit is available.

5. Checks the integrity of the signal circuit to the PCM.

6. Checks the integrity of the signal circuit to the PCM.

7. Certain RTV silicone gasket materials give off vapors that can contaminate the HO2S. There is also a possibility of silicone contamination caused by silicone in fuel. If it appears that the sensors are contaminated by silicone and all silicone sealant is a none silicone base, advise customer to try a different fuel company. A fuel filler restrictor missing, indicates leaded fuel may have been used.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Important: If any DTCs are set (Except P0153), refer to those DTCs before proceeding with this diagnostic table.

1. Install the scan tool.
2. Start the and idle engine until normal operating temperature is reached.
3. Operate vehicle within parameters specified under Conditions for setting the DTC in the supporting text.
4. Using the scan tool, monitor FAIL THIS IGN. under DTC Info.

Does the scan tool indicate DTC P0133 test failed?

--

Go to Step 3

Go to Diagnostic Aids

3 | Did the scan tool also indicate P0153 test failed? | -- | Go to Step 8 | Go to Step 4
4 |

1. Perform Exhaust System Leak Test. Refer to Exhaust System (6F). After Exhaust System Leak Test has been performed, return to this diagnostic.
2. If an exhaust leak is found, repair as necessary.

Was an exhaust leak isolated?

--

Go to Step 2

Go to Step 5

5 | Visually/physically inspect the following items:

• | Ensure that the Bank 1 HO2S 1 is securely installed.

• | Check for corrosion on terminals.

• | Check terminal tension (at Bank 1 HO2S 1 and at the PCM).

• | Check for damaged wiring.

Was a problem found in any of the above areas?

--

Go to Step 9

Go to Step 6

6 |

1. Disconnect Bank 1 HO2S 1 and jumper HO2S low (PCM side) signal circuit to ground.
2. Using the scan tool, monitor Bank 1 HO2S 1 voltage on the Engine 1 Data List.

Does the scan tool indicate voltage within the specified values?

375 mV-525 mV

Go to Step 7

Go to Step 10

7 |

1. Jumper Bank 1 HO2S 1 high and low (PCM side) signal circuits to ground.
2. Using the scan tool, monitor Bank 1 HO2S 1 voltage.

Does the scan tool indicate voltage below specified value?

200 mV

Go to Step 12

Go to Step 11

8 | Important: Before replacing a sensor, the cause of the contamination must be determined and corrected. Check for the following conditions:

• | Fuel contamination.

• | Use of improper RTV sealant.

• | Engine oil/coolant consumption.

Replace the affected Heated Oxygen sensor. Refer to Heated Oxygen Sensor Replacement .

Is the action complete?

--

Go to Step 13

--

9 | Repair condition as necessary. Is the action complete? | -- | Go to Step 13 | --
10 | Repair open Bank 1 HO2S 1 low signal circuit or grounded Bank 1 HO2S 1 high signal circuit. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5). Is the action complete? | -- | Go to Step 13 | --
11 | Repair open Bank 1 HO2S 1 high signal circuit or faulty PCM connections. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5). Is the action complete? | -- | Go to Step 13 | --
12 | Replace Bank 1 HO2S 1. Refer to Heated Oxygen Sensor Replacement . Is the action complete? | -- | Go to Step 13 | --
13 |

1. Using the scan tool, select DTC, Clear Info.
2. Start the engine and idle at normal operating temperature.
3. Select DTC, Specific, then enter the DTC number which was set.
4. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 14

Go to Step 2

14 | Using the scan tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK