P0055 medium Severity

P0055: HO2S Heater Resistance (Bank 1, Sensor 3)

May not immediately affect drivability; can reduce fuel economy and increase emissions

Overview

P0055 indicates a fault in the heated oxygen sensor heater circuit resistance for Bank 1, Sensor 3, often due to electrical issues or sensor failure

Common Symptoms

  • Check Engine Light illuminated
  • Decreased fuel economy
  • Delayed cold start
  • Increased exhaust emissions
  • Possible rough idle

Most Common Causes

Faulty heated oxygen sensor (Bank 1, Sensor 3) high

Internal heater element failure or incorrect resistance detected

Damaged or corroded wiring/connectors in heater circuit high

Open or short in wiring can lead to out-of-spec resistance

Blown fuse or faulty relay supplying heater circuit medium

Power supply interruptions can trigger the code

PCM/ECM driver fault low

Rare but possible internal controller issue

Diagnostic Steps

  1. Confirm presence of P0055 code with an OBD-II scanner
    Expected: P0055 code stored; possible related codes
    Interpretation: Verify that the code is current and not historical
  2. Visually inspect wiring and connectors for Bank 1 Sensor 3 heater circuit
    Expected: No frayed wires, corrosion, or loose connections
    Interpretation: Damaged wiring/connectors often cause resistance faults
  3. Check fuses and relays related to the oxygen sensor heater circuit
    Expected: Fuse intact; relay functioning
    Interpretation: Blown fuse or bad relay can interrupt heater supply
  4. Measure heater resistance with a multimeter at the sensor
    Expected: Resistance within manufacturer spec
    Interpretation: Out-of-spec reading indicates heater or wiring fault
  5. Test for proper voltage at sensor heater connector with ignition on
    Expected: Battery voltage present per OEM spec
    Interpretation: Lack of voltage suggests supply circuit issue

Repair Solutions

Replace oxygen sensor Bank 1 Sensor 3 medium
Estimated Cost: $100 - $250

Typical repair when internal heater is defective

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $200

Cost varies with extent of wiring damage

Replace blown fuse or faulty relay easy
Estimated Cost: $5 - $50

Simple electrical part replacement

PCM/ECM repair or replacement hard
Estimated Cost: $500 - $1500

Only after all other causes are ruled out

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming oxygen sensor replacement solves code without checking wiring or power supply

Frequently Asked Questions

Technical definition of P0055 OBD-II Code

Technically, the P0055 code represents HO2S Heater Resistance (Bank 1, Sensor 3). It usually points to a fault within the Emissions.

Can P0055 cause engine damage?

This is a medium priority issue. May not immediately affect drivability; can reduce fuel economy and increase emissions

Symptoms associated with DTC P0055

Drivers often report: Check Engine Light illuminated, Decreased fuel economy, Delayed cold start when this code is present.

Why is my car throwing a P0055 code?

The most common causes are: Faulty heated oxygen sensor (Bank 1, Sensor 3), Damaged or corroded wiring/connectors in heater circuit, Blown fuse or faulty relay supplying heater circuit.

Is P0055 expensive to fix?

Expect to pay around $50 if the issue is a Replace blown fuse or faulty relay, but up to $1500 if the PCM/ECM repair or replacement needs replacement.

What cars are affected by the P0055 code?

This is a universal code. You might see P0055 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

User Comments (0)

Share your experience or ask a question about this code.

Be the first to share your experience with P0055!