INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)
CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI NO. 2 FUSE)
CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - EFI NO. 2 FUSE)
DTC P0038 Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)
DTC P0057 Oxygen Sensor Heater Control Circuit Low (Bank 2 Sensor 2)
DTC P0058 Oxygen Sensor Heater Control Circuit High (Bank 2 Sensor 2)
DTC P0141 Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
DTC P0161 Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
Description DTC P0038 P0057 P0058 P0141 P0161
HINT:
- Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
- When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen (HO2) sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.
- The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The HO2 sensor heater circuit uses a relay on the +B side of the circuit.
DTC Code | DTC Detection Condition | Trouble Area |
P0037 P0057 | The Heated Oxygen (HO2) sensor heater (bank 1, 2 sensor 2) current is below 0.3 A (1 trip detection logic). |
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P0038 P0058 | The Heated Oxygen (HO2) sensor heater (bank 1, 2 sensor 2) current is higher than 2 A (1 trip detection logic). |
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P0141 P0161 | The cumulative heater resistance correction value exceeds the acceptable threshold (2 trip detection logic). |
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HINT:
- Bank 1 refers to the bank that includes the No. 1 cylinder.
- Bank 2 refers to the bank that does not include the No. 1 cylinder.
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.
Monitor description
The sensing portion of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature, and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor.
- Heated oxygen sensor heater range check (P0037, P0038, P0057 and P0058):
- The ECM monitors the current applied to the HO2 sensor heater to check the heater for malfunctions. If the current is below the threshold value, the ECM will determine that there is an open circuit in the heater. If the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
- Example:
- The ECM stores DTC P0038 or P0058 when the current in the HO2 sensor heater is higher than 2 A. Conversely, when the heater current is below 0.3 A, DTC P0037 or P0057 is stored.
- Example:
- The ECM monitors the current applied to the HO2 sensor heater to check the heater for malfunctions. If the current is below the threshold value, the ECM will determine that there is an open circuit in the heater. If the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
- Heated oxygen sensor heater performance (P0141 and P0161):
- After the accumulated heater ON time exceeds 100 seconds, the ECM calculates the heater resistance using the battery voltage and the current applied to the heater. If the resistance is above the threshold value, the ECM will determine that there is a malfunction in the HO2 sensor heater and store DTCs P0141 and P0161.
Wiring diagram
Inspection procedure
HINT:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
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Disconnect the heated oxygen (HO2) sensor connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
for Bank 1 Sensor 2 Tester Connection Condition Specified Condition 1 (HT1B) - 2 (+B) 20°C (68°F) 11 to 16 ? 1 (HT1B) - 4 (E2) Always 10 k? or higher for Bank 2 Sensor 2 Tester Connection Condition Specified Condition 1 (HT2B) - 2 (+B) 20°C (68°F) 11 to 16 ? 1 (HT2B) - 4 (E2) Always 10 k? or higher
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OK | |
2.CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)
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Measure the voltage according to the value(s) in the table below.
Standard Voltage:
for Bank 1 Sensor 1 Tester Connection Switch Condition Specified Condition C20-2 (+B) - Body ground Ignition switch ON 11 to 14 V for Bank 2 Sensor 1 Tester Connection Switch Condition Specified Condition C21-2 (+B) - Body ground Ignition switch ON 11 to 14 V
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OK | |
3.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
for LHD Tester Connection Condition Specified Condition C20-1 (HT1B) - C45-48 (HT1B) Always Below 1 ? C21-1 (HT2B) - C45-47 (HT2B) Always Below 1 ? for RHD Tester Connection Condition Specified Condition C20-1 (HT1B) - C46-48 (HT1B) Always Below 1 ? C21-1 (HT2B) - C46-47 (HT2B) Always Below 1 ? Standard Resistance (Check for Short):
for LHD Tester Connection Condition Specified Condition C20-1 (HT1B) or C45-48 (HT1B) - Body ground Always 10 k? or higher C21-1 (HT2B) or C45-47 (HT2B) - Body ground Always 10 k? or higher for RHD Tester Connection Condition Specified Condition C20-1 (HT1B) or C46-48 (HT1B) - Body ground Always 10 k? or higher C21-1 (HT2B) or C46-47 (HT2B) - Body ground Always 10 k? or higher
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OK | |
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4.INSPECT FUSE (EFI NO. 2)
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Remove the EFI NO. 2 fuse from the engine room relay block.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition EFI NO. 2 fuse Always Below 1 ?
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OK | |
5.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI NO. 2 FUSE)
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Remove the EFI NO. 2 fuse from the engine room relay block.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection Condition Specified Condition C20-2 (+B) - EFI NO. 2 fuse (2) Always Below 1 ? C21-2 (+B) - EFI NO. 2 fuse (2) Always Below 1 ? Standard Resistance (Check for Short):
Tester Connection Condition Specified Condition C20-2 (+B) or EFI NO. 2 fuse (2) - Body ground Always 10 k? or higher C21-2 (+B) or EFI NO. 2 fuse (2) - Body ground Always 10 k? or higher
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OK | |
6.CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - EFI NO. 2 FUSE)
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Remove the EFI NO. 2 fuse from the engine room relay block.
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Remove the integration relay from the engine room relay block.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection Condition Specified Condition EFI NO. 2 fuse (1) - 1B-4 Always Below 1 ? Standard Resistance (Check for Short):
Tester Connection Condition Specified Condition EFI NO. 2 fuse (1) or 1B-4 - Body ground Always 10 k? or higher
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OK | |
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