Inspect heated oxygen sensor (heater resistance)
Check terminal voltage (+B OF HO2 sensor)
Inspect integration no.1 relay (EFI)
Check harness and connector (HO2 sensor - integration relay)
Check harness and connector (HO2 sensor - ECM)
Check whether DTC output recurs
DTC P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
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)
Description
- Refer to DTC P0136 .
HINT:
- When any of these DTCs is 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 engine 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 current is below 0.3 A (1 trip detection logic). |
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| P0038 P0058 | The Heated Oxygen (HO2) sensor heater current is higher than 2 A (1 trip detection logic). |
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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 O2 sensor heater to check the heater for malfunctions. If the current is below the threshold value, the ECM determines that there is an open circuit in the heater. If the current is higher than the threshold value, the ECM determines that there is a short circuit in the heater. The ECM constantly monitors the current applied to the heater. If the ECM detects an open or short circuit, the ECM turns the MIL on and stores a DTC. If a malfunction is detected, the ECM cuts off the current applied to 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.
Wiring diagram
CONFIRMATION DRIVING PATTERN
These DTCs are stored when the engine idles for 110 seconds or more.
Inspection procedure
HINT:
- Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
- 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.
- Bank 1 refers to the bank that includes the No. 1 cylinder*. *: The No. 1 cylinder is the cylinder which is farthest from the transmission.
- 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.
| 1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE) |
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Disconnect the C20 or C56 heated oxygen (HO2) sensor connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition 1 (HT1B) - 2 (+B) 20°C (68°F) 11 to 16 ? 1 (HT1B) - 4 (E1) Always 10 k? or higher 1 (HT2B) - 2 (+B) 20°C (68°F) 11 to 16 ? 1 (HT2B) - 4 (E1) Always 10 k? or higher
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| OK | |
| 2.CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR) |
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Disconnect the C20 or C56 HO2 sensor connector.
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Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection Switch Condition Specified Condition C20-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V C56-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V Result Result Proceed to NG A OK B
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| A | |
| 3.INSPECT INTEGRATION NO.1 RELAY (EFI) |
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Remove the integration relay from the engine room relay block.
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Inspect the EFI MAIN fuse.
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Remove the EFI MAIN fuse from the integration relay.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition EFI MAIN fuse Always Below 1 ? -
Reinstall the EFI MAIN fuse.
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Inspect the EFI relay.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition 1C-1 - 1B-4 No battery voltage applied to terminals 1B-2 and 1B-3 10 k? or higher Battery voltage applied to terminals 1B-2 and 1B-3 Below 1 ?
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| OK | |
| 4.CHECK HARNESS AND CONNECTOR (HO2 SENSOR - INTEGRATION RELAY) |
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Check the 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:
Tester Connection Condition Specified Condition EFI NO. 2 fuse Always Below 1 ? -
Reinstall the EFI NO. 2 fuse.
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Disconnect the C20 or C56 HO2 sensor connector.
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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:
Tester Connection Condition Specified Condition C20-2 (+B) - 1B-4 Always Below 1 ? C56-2 (+B) - 1B-4 Always Below 1 ? C20-2 (+B) or 1B-4 - Body ground Always 10 k? or higher C56-2 (+B) or 1B-4 - Body ground Always 10 k? or higher
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| OK | |
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| 5.CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM) |
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Disconnect the C20 or C56 HO2 sensor connector.
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Disconnect the C45 ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition C20-1 (HT1B) - C45-45 (HT1B) Always Below 1 ? C56-1 (HT2B) - C45-44 (HT2B) Always Below 1 ? C20-1 (HT1B) or C45-45 (HT1B) - Body ground Always 10 k? or higher C56-1 (HT2B) or C45-44 (HT2B) - Body ground Always 10 k? or higher
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| OK | |
| 6.CHECK WHETHER DTC OUTPUT RECURS |
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Connect the intelligent tester to the DLC3.
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Turn the engine switch on (IG).
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Turn the tester on.
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Clear DTCs .
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Start the engine.
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Allow the engine to idle for 2 minutes or more.
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Enter the following menus: Powertrain / Engine and ECT / DTC.
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Read DTCs.
Result Result Proceed to No DTC is output A P0037, P0038, P0057 and/or P0058 are output B
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| A | |
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