P0155 Code: Honda Civic (2022-2024) - Causes, Symptoms & Fixes

No recalls found in NHTSA database

No owner complaints found for this make/model/year/issue combination in the provided data.

Note: This diagnostic guide combines general OBD-II knowledge with typical Honda Civic 2022–2024 behavior. The exact sensor bank mapping can vary by engine configuration. P0155 is a heated O2 sensor fault in the OBD-II code set, commonly described as an O2 Sensor Heater Circuit Malfunction.

CODE MEANING AND SEVERITY

• Code: P0155

• Full description: O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

• What it means in plain terms: The heating element inside the oxygen sensor (the heater) on Bank 2 Sensor 1 is not functioning as it should. The heater helps the sensor reach operating temperature quickly for accurate readings. A heater fault can cause slow catalyst warm-up, elevated emissions, and degraded fuel economy.

• Severity on a 2022–2024 Honda Civic: Moderate. The MIL (Check Engine) is typically illuminated. Persistent issues can cause reduced fuel economy, potential emissions failures, and delayed readiness of onboard diagnostics. Usually not an immediate safety risk, but navigation to a fix is advised to avoid long-term catalyst or engine inefficiency.

• Important note about bank sensor naming on a Civic: For inline-4 Hondas (like many Civics), the exact bank/sensor labeling can differ by engine type and market. P0155 is defined in the OBD-II standard as a Bank 2 Sensor 1 heater issue, but the physical sensor location may map differently on a specific 2022–2024 Civic. A proper repair relies on confirming the actual sensor referenced by the vehicle’s service data and scan tool.

COMMON CAUSES ON HONDA CIVIC

• Faulty O2 sensor heater element: The sensor itself has failed or the heater inside has burned open or shorted.
• Damaged or corroded wiring/connector to the O2 sensor heater circuit: Broken insulation, heat damage near the exhaust, or loose connectors.
• Blown fuse or problem in the heater circuit power/ground feed: A fuse protecting the heater circuit could be blown; a relay or PCM output could be the issue.
• Wiring harness chafing or grounding issues: Short to ground or open circuit due to harness wear.
• Exhaust leaks upstream of the sensor: Leaks can cause incorrect readings and fault the sensor’s heater circuit logic.
• PCM/ECU control issue: Less common, but the engine computer can fail to power the heater circuit correctly.
• Sensor location confusion or mixed diagnostics: In some Civics, multiple O2 sensors exist (upstream and downstream). A fault could be misattributed if the wrong sensor is tested.
• Contamination or exposure to excessive heat: Sensor failure can be accelerated by heat, oil, coolant, or fuel contamination.

SYMPTOMS

• Check Engine Light (MIL) illuminated with P0155 stored or pending.
• Deteriorated fuel economy or performance symptoms (mild hesitation, slight roughness) as the sensor fails to heat quickly enough.
• Possible elevated emissions test readings or failure (catalyst efficiency issue could follow if not addressed).
• Inconsistent OBD readiness monitors (some monitors may not complete until the sensor heats properly).
• No obvious mechanical noise; symptoms are mostly related to sensor readings, fuel mixture, and emissions.

DIAGNOSTIC STEPS

Note: Safety first. Work with the engine cool and follow proper electrical safety. If you’re not comfortable, seek a professional.

A. Confirm the code and data

• Use a capable scan tool to verify P0155 and capture freeze-frame data.
• Check for related codes (P0150–P0154, P0130–P0135, or P0030–P0034 family) to understand if other O2 sensor circuits or heater controls are affected.
• Review readiness monitors. If the heater-related monitors aren’t ready, don’t prematurely replace parts.

B. Visual inspection

• Inspect the O2 sensor(s) and wiring near the exhaust for obvious signs of heat damage, abrasion, or corrosion at the connector.
• Look for oil or coolant contamination around the sensor that could foul readings or heater circuits.
• Check for exhaust leaks around the sensor, which can affect readings and sensor operation.

C. Electrical checks (heater circuit)

• Identify which O2 sensor the code references (Bank 2 Sensor 1 in the code, but verify with service data for your exact Civic engine).
• Check fuses: Locate and inspect the fuse(s) associated with the O2 sensor heater circuit. Replace if blown.
• Inspect the connector and wiring harness:
  • Look for melted insulation, broken wires, or corrosion at the sensor connector.
  • Disconnect and reseat the connector; look for bent pins.
• Power/ground check:
  • With the engine off, back-probe the heater circuit wires to verify presence of a power supply (12V) and a solid ground when commanded.
  • With the engine at operating temperature, monitor the heater circuit current/voltage using a DMM or scan tool. In a healthy circuit, the PCM should power the heater and you should see voltage being supplied to the heater coil when the engine is starting/at operating temp.
• Continuity and resistance check (sensor removed):
  • Remove the O2 sensor and measure the heater element resistance across the heater terminals. Compare to the OEM/spec figure if available (typical heater resistances for O2 sensors are in a low-ohm range; a circuit open or very high resistance indicates a bad sensor).
  • If resistance is within spec but no voltage is present at the heater harness under commanded heating conditions, suspect wiring/PCM control as the issue.
• Sensor swap test (optional, if you have a known-good spare sensor):
  • Swap Bank 2 Sensor 1 with a known-good sensor to see if the DTC clears or transfers. If it goes away, the original sensor is failing.

D. Other checks

• Verify there are no exhaust leaks before or around the sensor that could cause abnormal readings or misinterpretation of heater status.
• If you replaced the sensor or repaired wiring and the code persists, a PCM/ECU fault or software issue could be involved; reflash or reprogramming may be required per dealer/service data.

E. After repair verification

• Clear codes and test drive to ensure the code does not return.
• Check OBD readiness monitors again to verify all monitors complete successfully.

RELATED CODES

• O2 sensor family and heater circuit codes:
  • P0150–P0154: O2 Sensor Heater Malfunction on various sensors/banks
  • P0130–P0135: O2 Sensor Circuit Malfunction / Reference voltage / Sensor voltage (Bank 1 Sensor 1, etc.)
  • P0030–P0034: O2 Sensor Heater Control Circuit (various banks/sensors)
• Other related emissions codes to watch after fix:
  • P0420: Catalyst System Efficiency Below Threshold
  • P0430: Catalyst System Efficiency Below Threshold (Bank 2)
• These related codes can appear if the O2 sensor heater fault affects catalytic efficiency or if the readings were consistently off.

REPAIR OPTIONS AND COSTS (2025 PRICES)

Prices are approximate and vary by region, shop rate, and whether OEM or aftermarket parts are used.

• O2 sensor replacement (Bank 2 Sensor 1 — or the affected sensor):
  • Parts: $40–$200 (aftermarket sensors; OEM typically higher)
  • Labor: 0.5–1.5 hours
  • Total estimate: $150–$350 (independent shop); dealers may charge $250–$450 all-in.
• O2 sensor wiring/connector repair:
  • Parts: minimal (fuse, wiring if needed)
  • Labor: 0.3–1.0 hours
  • Total estimate: $50–$200 (depending on extent of harness repair)
• Fuse/relay replacement for heater circuit:
  • Parts: $0–$20
  • Labor: minimal
  • Total estimate: $0–$60
• PCM/ECU issues or software reflash/reprogramming:
  • Parts: $0–$400 (used/repair; dealer may charge more)
  • Labor/Programming: $150–$600
  • Total estimate: $300–$1000 (depending on whether reflashing suffices)
• If catalytic converter or other emissions components are implicated due to prolonged rich/lean conditions:
  • Catalytic converter replacement is significantly more expensive and may range from $800–$2,500 (parts plus labor), depending on OEM/aftermarket and vehicle specifics.
• DIY approach (potential savings):
  • Sensor replacement: parts $40–$150; you save labor but must supply your own time and appropriate tools.
  • Cautions: Correct sensor torque specification, anti-seize usage (if included by OEM), and proper sensor wiring handling.

DIY VS PROFESSIONAL

• DIY feasibility:
  • Replacing an O2 sensor is a common DIY task for someone with basic automotive tools (socket/wrench set, oxygen sensor socket, electrical cleaner, multimeter if testing).
  • Pros: Cost savings, quick turnaround for a straightforward sensor replacement.
  • Cons: Getting the correct sensor type and bank mapping for your exact Civic model is essential; improper installation can cause leaks or sensor failure.
• When to see a professional:
  • If you’re not comfortable diagnosing the heater circuit (fuse/PCM wiring, harness reliability, back-probing a live heater circuit, high-temperature environment near exhaust), seek a professional.
  • If you’ve replaced the sensor and the DTC persists, a professional with factory scan tools can verify PCM outputs and confirm wiring integrity or perform a controlled component swap to identify a faulty sensor vs. ECU issue.
  • If you suspect a PCM/ECU fault or dealer-level programming is required, you should go to a dealer or shop with Honda-specific software.

PREVENTION

• Regular, quality maintenance:
  • Replace O2 sensors according to Honda’s maintenance schedule or OEM recommendations; many Civics use O2 sensors that last 60k–100k miles but can fail earlier in harsh conditions.
• Keep exhaust system intact:
  • Repair exhaust leaks promptly; leaks can cause erroneous O2 sensor readings and heater control faults.
• Protect sensor wiring:
  • Inspect and protect O2 sensor wiring harnesses from heat and abrasion, especially where the harness passes near the exhaust manifold or heat shields.
• Use superior fuel and engine care:
  • Use quality fuels and maintain the air and fuel delivery system to minimize sensor contamination and stress.
• Monitor and address codes promptly:
  • If P0155 appears, address the root cause quickly to prevent catalyst inefficiency or excessive emissions, which can lead to failed emissions tests and potential warranty implications.

If you’d like, I can tailor this guide to your exact Civic variant (engine code, trim, and whether your car has Bank 1/Bank 2 labeling present in your service data) to more precisely map P0155 to the correct sensor location and provide step-by-step DIY instructions with torque specs and wiring diagrams.