P0135 - O2 Sensor Heater Circuit Bank 1 Sensor 1
P0135 is a generic powertrain diagnostic trouble code indicating O2 Sensor Heater Circuit Bank 1 Sensor 1. It relates to the Fuel & Air Metering system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Fuel & Air Metering |
| Fault Index | 35 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0135 mean?
The engine computer has detected a malfunction in the heater circuit of the Bank 1 Sensor 1 oxygen sensor. The internal heater warms the sensor to operating temp quickly.
Severity Level & Driveability Details
Severity: Moderate
The sensor takes too long to warm up, keeping the engine in open loop for longer, which increases fuel consumption and emissions.
Common Symptoms of P0135
- Malfunction indicator lamp (MIL) turns on due to O2 sensor heater failure.
- Lower fuel economy on short trips.
Typical Causes for P0135
- Failed internal heating element in the O2 sensor.
- Blown O2 sensor heater fuse.
- Corroded sensor connector or wiring.
Diagnostic and Troubleshooting Steps
Measure resistance across the O2 sensor heater terminals using a digital multimeter. A normal heater has 5-20 ohms. An infinite resistance (open circuit) confirms the internal heater is burnt out.
Typical Repairs and Fixes
- Replacing the Bank 1 Sensor 1 oxygen sensor to resolve heater coil failure.
- Replacing a blown O2 heater circuit fuse.
- Repairing wiring damage.
Sensor Location & Parts Involved
The oxygen sensor is located in the exhaust pipe, either upstream (Sensor 1) or downstream (Sensor 2) of the catalytic converter.
Clearing Code & Recurrence
Clear the code using an OBD2 scanner and perform a drive cycle to reset the monitors.
Emissions & Smog Inspection Impact
Can cause rich running (excess carbon monoxide and hydrocarbons) or lean running (excess nitrogen oxides).
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Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- EPA Emissions OBD Guide
- SAE J2012 specifications
Frequently Asked Questions about P0135
What does the Bank 1 Sensor 1 O2 sensor heater code P0135 mean?
The engine control module logged P0135 after detecting a fault specifically in the oxygen sensor heater circuit for Bank 1, Sensor 1. The heater circuit is responsible for rapidly warming the O2 sensor to its operating temperature (~600°F) upon cold start.
Is it safe to drive with the Bank 1 Sensor 1 O2 sensor heater code P0135 active?
Yes, but engine fuel efficiency will decrease until the sensor is replaced.
How much does it cost to repair a Bank 1 Sensor 1 O2 sensor heater code P0135 fault?
Replacement parts cost $80-$200. Labor to replace the sensor is $70-$150 depending on rust and access.
What are the common causes of the Bank 1 Sensor 1 O2 sensor heater code P0135?
Trigger conditions for the Bank 1 Sensor 1 O2 sensor heater code P0135 include: Failed oxygen sensor heater circuit for Bank 1 Sensor 1 (typically a burned-out internal heater element)., Corroded wiring or loose electrical connector at the sensor plug., Blown O2 sensor circuit fuse..
Can I clear the check engine light for Bank 1 Sensor 1 O2 sensor heater code P0135?
Clear the code using an OBD2 scanner and perform a drive cycle to reset the monitors.
Will the Bank 1 Sensor 1 O2 sensor heater code P0135 cause an inspection failure?
Can cause rich running (excess carbon monoxide and hydrocarbons) or lean running (excess nitrogen oxides).