The heated oxygen sensor (HO2S) is a sensor used to detect the oxygen content in the exhaust. The powertrain control module (PCM) supplies the sensor with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The sensor varies the voltage based on the oxygen content in the exhaust. When the exhaust stream is lean, more oxygen, the sensor produces a low voltage signal. When the exhaust stream is rich, indicating less oxygen, the sensor produces a high voltage signal. The PCM monitors the HO2S signal during Closed Loop. To correct for rich or lean conditions, the PCM adjusts the injector pulse width.
• | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0155, P0201-P0208, P0300, P0410, P0440, P0442, P0443, P0446, P0449, P1153, P1415, P1416, or P1441 are not set. |
• | The engine speed is between 1,200-2,800 RPM. |
• | The throttle position (TP) angle is more than 3 percent. |
• | The mass air flow (MAF) is between 15-35 g/s. |
• | The system voltage is between 9-18 volts. |
• | The coolant temperature is more than 75°C (167°F). |
• | The engine run time is more than 202 seconds (approximately 3.5 minutes). |
• | Closed Loop fuel is enabled. |
• | The exhaust gas recirculation (EGR) flow diagnostic test is not active. |
• | The secondary air injection (AIR) diagnostic test is not active. |
• | The catalyst diagnostic test is not active. |
• | The transmission is not in Park, Reverse, or Neutral. |
• | The above conditions are met for 3 seconds. |
HO2S bank 2 sensor 1 lean-to-rich average transition response time during the sample period was more than 219 milliseconds.
or
HO2S bank 2 sensor 1 rich-to-lean average transition response time during the sample period was more than 219 milliseconds.
or
The oxygen (O2) sensor voltage is between 325-625 mV.
• | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
• | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
• | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
• | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
• | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
• | Clear the MIL and the DTC with a scan tool. |
Notice: Do not solder heated oxygen sensor wires. Soldering the wires will result in the loss of the air reference to the sensor. Refer to Engine Electrical for proper wire and connection repair techniques.
Notice: Use the connector test adapter kit J 35616-A for any test that
requires probing the following items:
• The PCM harness connectors • The electrical center fuse/relay cavities • The component terminals • The component harness connector
Check for the following conditions:
• | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
• | Inspect the wiring harness for damage--If the harness appears OK, observe the scan tool while moving the connectors and the wiring harnesses that are related to the HO2S bank 2 sensor 1 sensor. A change in the display will indicate the location of the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections in Wring Systems. |
• | For intermittent conditions, refer to Symptoms - Engine Controls . |
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.
The numbers below refer to the step numbers on the diagnostic table.
When the system is operating correctly the HO2S voltage should toggle above and below the specified values.
The specified value is what is measured on a correctly operating system.
The specified value is what is measured on a correctly operating system.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
Important: If any other DTCs are set except the HO2S DTCs, refer to other DTCs first before proceeding with this table.
Does the voltage vary outside the specified values? | 325-625 mV | Go to Step 3 | Go to Step 4 | |||||||
3 |
Does the scan tool indicate that DTC P0153 is current? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
4 | Inspect for the following conditions:
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 5 | ||||||
Does the voltage measure near the specified value? | 450 mV | Go to Step 6 | Go to Step 8 | |||||||
Does the voltage measure near the specified value? | 0 mV | Go to Step 9 | Go to Step 7 | |||||||
7 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
8 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
9 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 | ||||||
10 |
Notice: Contamination of the oxygen sensor can result from the use of an inappropriate RTV sealant (not oxygen sensor safe) or excessive engine coolant or oil consumption. Remove the HO2S and visually inspect the portion of the sensor exposed to the exhaust stream in order to check for contamination. If contaminated, the portion of the sensor exposed to the exhaust stream will have a white powdery coating. Silicon contamination causes a high but false HO2S signal voltage (rich exhaust indication). The control module will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem. Eliminate the source of contamination before replacing the oxygen sensor. Important: Determine the cause of the contamination before replacing the sensor.
Did you complete the replacement? | -- | Go to Step 13 | -- | ||||||
11 | Test for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | ||||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | ||||||
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 | ||||||
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |