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P0135

Overview

Code

P0135

Code Type

P

Code Class

P0

System

Engine, Emissions

Severity Level

Low

Emissions Related

true

Drivability Impact

Minor

Diagnostic Protocol

OBD2

Freeze Frame Useful

true

Code Definition

Diagnostic trouble code P0135 indicates a malfunction in the oxygen sensor heater circuit for Bank 1 Sensor 1

Symptoms

Check Engine Light illuminated; Delayed closed-loop operation

Overview applies to this diagnostic code.

Affected Systems

On This Page

  • Code Definition

  • Symptoms

  • Affected Systems

  • Possible Causes

  • Diagnostic Steps

  • Drive Safety Notes​

More Resources

The heater circuit helps the oxygen sensor reach operating temperature quickly

Possible Causes

Faulty oxygen sensor heater; Wiring or fuse issues

Diagnostic Steps

1 Confirm the fault code; 2 Inspect heater circuit wiring and fuse; 3 Measure heater resistance; 4 Replace the oxygen sensor if heater is faulty

Drive Safety Notes

Driving is safe, but emissions may increase during cold starts

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