P0135
O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
Description
O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1). This powertrain diagnostic trouble code covers the engine, the fuel and ignition systems, emission control and the transmission.
OBD Codes Details
Possible Causes
Faulty sensor, intake leak, clogged fuel filter, weak fuel pump, damaged wiring
Solution
Check for intake leaks, inspect and clean the sensor, measure fuel pressure, compare live data against the expected range
Symptoms
- Check engine light illuminated
- No noticeable drivability symptoms in most cases
- Longer engine warm-up before closed-loop operation
- Slightly reduced fuel economy
- Failed emissions test
Diagnostic Recommendations
- Check O2 sensor heater fuse and relay
- Test heater circuit resistance at the sensor connector
- Inspect wiring for heater circuit damage or corrosion
- Verify battery voltage reaches the heater circuit
- Replace O2 sensor if heater circuit is open or shorted
Repair Cost Estimate
- O2 sensor replacement: $150-400
- Fuse/relay replacement: $10-40
- Wiring repair: $80-200
- Diagnostic scan: $80-150
- Total diagnostic and repair: $150-600
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
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