P0155 Code: Dodge Charger (2021-2023) - Causes, Symptoms & Fixes

Section 1 — Code Meaning and Severity

• Code: P0155
• Full definition: OBD-II diagnostic trouble code for O2 Sensor Heater Circuit Malfunction on Bank 2 Sensor 2 (the downstream oxygen sensor on the “Bank 2” side of the engine, after the catalytic converter).
• What it means: The heater element inside the Bank 2 Sensor 2 oxygen sensor is not heating properly, or the circuit that feeds that heater is open/shorted or otherwise not controlling heat as designed. The O2 sensor heater helps the sensor reach its operating temperature faster so it can provide accurate readings sooner.
• Severity and impact:
  • Emissions impact: Increases the chance of elevated emissions because the sensor may not reach proper operating temperature quickly.
  • Fuel economy and drivability: Flexibility in driving may be reduced; in many cases you’ll still drive normally, but fuel trims and catalyst efficiency might be affected until the sensor warms properly.
  • MIL: The check engine light (malfunction indicator lamp) is typically on, and the code will be stored.
  • Readiness: Emission readiness monitors may not complete until the issue is repaired and the system has cycled.

Data note: The provided data for 2021–2023 Dodge Charger shows no NHTSA owner complaints and no recalls in the database for this issue. No recalls found in NHTSA database.

Section 2 — Common Causes on Dodge Charger

• Faulty Bank 2 Sensor 2 O2 sensor itself (heater element failed or sensor degraded).
• Damaged, corroded, or loose wiring harness or connector for Bank 2 Sensor 2 heater circuit.
• Open or shorted fuse/relay feeding the O2 sensor heater circuit.
• Poor or floating sensor ground related to the downstream sensor.
• Wiring harness chafing or a damaged earth/ground path near the sensor.
• PCM/ECU output failure or a software fault affecting the heater control (less common, but possible).
• Exhaust leaks upstream or downstream of the sensor (false readings can appear and affect heater operation tests).

Note: In modern Chargers, Bank 2 Sensor 2 is the downstream sensor on the side opposite Bank 1. It’s less directly involved in air/fuel mix correction than the upstream sensors, but its heater circuit failure still triggers the P0155 fault.

Section 3 — Symptoms

• Check Engine Light (MIL) illuminated with code P0155 stored.
• Possible drop in fuel economy or slightly altered fuel trims once the vehicle adapts.
• In some cases, no obvious drivability symptoms other than the MIL; the vehicle may run normally if the sensor heater issue doesn’t affect catalytic efficiency significantly.
• Possible rough idle or hesitation only if the downstream sensor heater issue is accompanied by another fault in the exhaust or sensor system.
• O2 sensor-related diagnostic readiness monitors may be incomplete until the heater circuit fault is repaired.

Section 4 — Diagnostic Steps

Confirm and document

• Use a capable OBD-II scanner to confirm P0155 and record freeze-frame data, current fuel trims, engine temperature, and catalyst temperatures if your tool provides that.
• Check for any other codes stored (especially related O2 sensor codes such as P0135/P0141 for other banks, misfire codes, or catalyst codes).

Visual inspection

• Inspect the Bank 2 Sensor 2 downstream O2 sensor and its wiring harness for:
  • Visible damage, cuts, or chafing.
  • Corrosion on the connectors.
  • Loose or bent pins.
  • Signs of heat damage around the sensor or harness.

Check fuses and power supply

• Locate the fuse/relay box(es) that supply power to the O2 sensor heater circuit (often labeled for O2 sensors or heater circuits). Check for blown fuses or a faulty relay.
• If a fuse is blown, replace it and re-check the system. If the fuse blows again, there is likely a short or wiring problem.

Basic electrical test on the heater circuit

• With the ignition off, unplug Bank 2 Sensor 2 connector and inspect terminals.
• Use a digital multimeter (DVOM) to measure heater circuit resistance (across the heater element pins) and compare to the service spec. Typical O2 sensor heater resistance is in the low-ohm range (for many sensors roughly between 5–15 ohms, but consult the factory spec for your exact sensor). An open circuit (infinite resistance) or a very low/short condition indicates a failed sensor heater.
• Check for continuity and resistance in the heater circuit wiring from the sensor to the connector in the harness. Look for breaks, frayed wiring, or pin grounding where it should not be grounded.

Inspect grounding and reference signals

• Ensure the sensor ground path is solid. A high-impedance or intermittent ground can cause heater operation issues or sensor misbehavior.
• Inspect the vehicle’s engine ground straps and the sensor ground connection point for corrosion or looseness.

Sensor health assessment

• If the heater circuit shows correct resistance and wiring continuity, reinstall the sensor and monitor live data with the scan tool:
  • Start the engine and allow it to reach operating temperature.
  • Check the Bank 2 Sensor 2 heater status (if your tool shows “HEATER” or “HEATER ON”).
  • If the heater never turns on, or the sensor data remains erroneous, the sensor itself is likely faulty and should be replaced.
• If you have access to a second, known-good Bank 2 Sensor 2, you can swap temporarily to confirm fault isolation (do this only if you’re comfortable and have the right part).

Exhaust and related systems

• Check for exhaust leaks upstream of Bank 2 Sensor 2. An exhaust leak can affect readings and the sensor’s heater behavior perception on some vehicles.
• Verify there are no other O2 sensor fault codes or upstream sensor issues that could be masking/compounding the problem.

After repair verification

• Clear codes with the scanner.
• Drive the vehicle through a reasonable drive cycle to allow readiness monitors to complete.
• Re-scan to ensure P0155 does not return.

Note: If the PCM/ECU is suspected, this is a more involved diagnosis and typically requires dealer-level tools and procedures. It’s far less common than a faulty sensor or harness issue.

Section 5 — Related Codes

• P0135, P0136, P0139 – O2 sensor heater circuit and signal issues for Bank 1 (or Bank 1 Sensor 1/2) may appear if the related sensor circuits are affected.
• P0141, P0146 – O2 sensor heater circuit issues for Bank 1 Sensor 2 or Bank 2 Sensor 2.
• P0154, P0156 – Other Bank 2 O2 sensor heater or signal problems.
• P0138, P0150–P0156 series – General O2 sensor circuit faults that can appear alongside or be confused with P0155 during diagnostics.

Section 6 — Repair Options and Costs (2025 Prices)

Note: Prices vary by region, shop, and whether you use OEM or aftermarket parts. The figures below are typical ranges you might see in 2025.

• Bank 2 Sensor 2 O2 sensor replacement (sensor only)

  • Parts: $60–$250 (OEM or aftermarket; OEM typically at the higher end)
  • Labor: 0.5–1.5 hours
  • Total: roughly $150–$400

• O2 sensor harness/connector repair or replacement

  • Parts: $20–$100 (if only harness/connector need replacing)
  • Labor: 0.5–1.0 hours
  • Total: roughly $100–$250

• O2 sensor heater circuit fuse/relay repair

  • Parts: $5–$30
  • Labor: 0.1–0.5 hours
  • Total: roughly $20–$150 (depending on whether there’s any wiring diagnosis required)

• Wiring harness repairs (if harness is chafed or damaged)

  • Parts: $10–$60 (insulation, heat shrink, connectors)
  • Labor: 1.0–2.0 hours
  • Total: roughly $100–$350

• PCM/ECU fault (less common)

  • Parts: $0–$600 (depending on whether reprogramming or replacement is needed)
  • Labor: 1.0–2.0 hours (plus software/diagnostic time)
  • Total: roughly $150–$1200

• Notes on cost

  • Labor rates vary widely by shop and region; dealers typically charge more than independent shops.
  • If the sensor is replaced under a warranty or extended warranty, your out-of-pocket cost could be much lower or zero.

Section 7 — DIY vs Professional

• DIY suitability

  • Good candidate if you’re comfortable with basic electrical testing, have a multimeter, and can safely access the O2 sensor and wiring.
  • Pros: Lower cost, learning experience, you control the parts quality.
  • Cons: Air/fuel sensor systems are part of emissions control; incorrect diagnostics or improper reassembly can lead to further issues or misreadings. Heated sensors reach high temperatures; take appropriate safety precautions and disconnect the battery when performing electrical tests.

• Professional suitability

  • Recommended for most owners, especially if you don’t have the right tools or if multiple codes are present.
  • Pros: Accurate diagnosis, proper testing of sensor heater circuits, verification of readiness monitors, and assurance that the issue is truly fixed.
  • Cons: Higher cost.

• DIY checklist (quick)

  • Verify no other codes or misfire symptoms.
  • Visually inspect wiring and connectors for Bank 2 Sensor 2.
  • Check fuse/relay for the heater circuit.
  • Measure heater resistance with a DVOM; verify proper continuity to the harness.
  • If wiring is OK and heater resistance is within spec, replace the Bank 2 Sensor 2 and re-test.
  • Clear codes and perform drive cycle to confirm.

Section 8 — Prevention

• Use good-quality fuel and maintain the exhaust system to avoid deposits that affect O2 sensor readings.
• Fix exhaust leaks promptly; leaks can cause false sensor readings and affect heater operation testing.
• Keep sensor connectors clean and dry. Use dielectric grease on connectors if appropriate (and per service guidelines) to resist corrosion.
• Inspect wiring harnesses for abrasion, especially where the harness runs near heat shields or moving components; repair damaged insulation promptly.
• Replace O2 sensors per the manufacturer’s recommended interval or when a fault is diagnosed; using an appropriate sensor type (OEM vs. quality aftermarket) helps ensure proper performance.
• When fueling or performing maintenance, avoid contaminating the exhaust with oil or coolant, which can contaminate sensors and skew readings.
• After any repair, clear codes, perform a complete drive cycle, and verify that the readiness monitors complete successfully.

Data notes and limitations

• The current data block provided with your request shows no official NHTSA complaints and no recalls for the Dodge Charger (2021–2023) relating to P0155. Therefore, this guide does not reference any specific recalls or TSBs from that data source.
• This guide relies on general OBD-II and O2 sensor knowledge, applied to the Dodge Charger platform. Exact fuse locations, sensor part numbers, and service procedures can vary by engine option and production date. Always check the vehicle’s service manual or a dealership for model-year-specific details.
• If you have a dealer or certified technician, they can retrieve OEM service information, wiring diagrams, and the exact electrical specs for Bank 2 Sensor 2 on your specific Charger configuration.