P0135
Category: Powertrain
Urgency:
Warning Severity
P0135: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
Code P0135 indicates that the internal heating element of the upstream Oxygen Sensor (Bank 1 Sensor 1) is not heating up to operating temperature fast enough.
Common Symptoms of P0135
- • Check Engine Light on
- • Engine takes longer to enter closed-loop fuel management
- • Increased fuel consumption and tailpipe emissions
Root Causes for Code P0135
- • Burnt out internal heater element inside the O2 sensor
- • Blown O2 sensor heater fuse or relay
- • Damaged or melted wiring harness near exhaust manifold
- • Corroded connector pins
Step-by-Step DIY Diagnostic & Inspection Guide
1
Check the O2 sensor heater fuse in the engine fuse box.
2
Measure resistance (ohms) across the heater pins of the sensor.
3
Replace Bank 1 Sensor 1 Oxygen Sensor if heater is open circuit.
Estimated Repair Costs
Replacement Parts:
$45 - $160
Shop Diagnostic / Labor:
$60 - $140
Total Estimated Cost:
$105 - $300
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