DTC P0135/21 Oxygen (A/F) Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) |
| DTC No. | DTC Detection Condition | Trouble Area |
| P0135/21 | Open or short in heater circuit of oxygen sensor for 0.5 seconds or more |
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| 1.INSPECT HEATED OXYGEN SENSOR |
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Disconnect the H6 sensor connector.
Measure the resistance of the sensor.
| Tester Connection | Condition | Specified Condition |
| 1 (HT) - 2 (+B) | 20°C (68°F) | 5 to 10 Ω |
| 1 (HT) - 4 (E) | - | 10 kΩ or higher |
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| OK | |
| 2.CHECK WIRE HARNESS (+B VOLTAGE) |
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Disconnect the H6 heated oxygen sensor connector.
Turn the ignition switch ON.
Measure the voltage of the wire harness side connector.
| Tester Connection | Specified Condition |
| H6-2 (+B) - Body ground | 9 to 14 V |
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| NG | |
| 3.INSPECT INTEGRATION RELAY (MAIN RELAY) |
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Remove the integration relay from the engine room junction block (Click here).
Measure the voltage of the MAIN relay.
| Tester Connection | Condition | Specified Condition |
| 1J-5 - Body ground | Ignition switch ON | 10 to 14 V |
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| OK | |
| 4.CHECK WIRE HARNESS (HEATED OXYGEN SENSOR - ECM, MAIN RELAY) |
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Disconnect the H6 sensor connector.
Disconnect the E12 ECM connector.
Disconnect the 1J connector from the engine room junction block (Click here).
Measure the resistance of the wire harness side connectors.
| Tester Connection | Specified Condition |
| H6-1 - E12-1 (HT1A) | Below 1 Ω |
| H6-2 (+B) - 1J-5 | Below 1 Ω |
| H6-1 or E12-1 (HT1A) - Body ground | 10 kΩ or higher |
| H6-2 (+B) or 1J-5 - Body ground | 10 kΩ or higher |
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| OK | |
| 5.CHECK IF DTC OUTPUT RECURS |
Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and turn the tester ON.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the DTCs.
| Display (DTC output) | Proceed to |
| No output | A |
| Heated oxygen sensor circuit DTCs | B |
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| A | ||
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