P0155 Code: Dodge Durango (2021-2024) - Causes, Symptoms & Fixes

Here is a comprehensive diagnostic guide for P0155 on 2021–2024 Dodge Durango. This guide follows the provided real NHTSA data: there are no owner complaints and no recalls found in the NHTSA database for this issue on these model years. Data limitations are noted where relevant.

CODE MEANING AND SEVERITY

• Code: P0155
• Full definition: O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
• Where it applies: Bank 2 Sensor 2 is the downstream oxygen sensor located after the catalytic converter on the second bank of cylinders.
• What it means: The heater element inside the downstream O2 sensor (Bank 2 Sensor 2) is not operating as intended. The heater helps the sensor reach operating temperature quickly so its readings are accurate sooner after startup.
• Severity:
  • Emissions/driveability impact: Moderate. Without a functioning heater, the sensor heats more slowly, which can delay accurate readings from the downstream sensor and may cause the PCM to run in non-ideal/open-loop behavior for longer or trigger emissions-related codes.
  • MIL/ownership impact: Likely fuel economy may degrade slightly and an MIL will set. Other related codes (e.g., P0420 Catalyst Efficiency) could appear if the downstream sensor readings are consistently thrown off, but P0155 itself is the heater fault.
• Data note: No recalls found in NHTSA for this issue on 2021–2024 Durango. No owner complaints were reported in the provided data.

COMMON CAUSES ON DODGE DURANGO

• Faulty Bank 2 Sensor 2 heater element (the sensor itself is bad).
• Damaged or corroded wiring harness to Bank 2 Sensor 2 heater circuit (pin damage, insulation wear, heat exposure near the exhaust).
• Faulty or blown fuse/relay powering the O2 sensor heater circuit.
• Bad or corroded sensor connector (pins not making good contact).
• Ground or power supply issue for the heater circuit (poor grounding, voltage drop).
• PCM or software glitch (rare; typically resolved with sensor replacement or updates).
• Secondary issues that can accompany: exhaust leaks or catalytic converter issues can complicate downstream sensor readings, though they do not cause the heater circuit fault themselves.

SYMPTOMS

• Check Engine Light (MIL) with P0155 stored.
• Downstream O2 sensor data not heating properly; slower warm-up of Bank 2 Sensor 2 readings in live data.
• Possible minor drop in fuel economy or slight hesitation during cold starts (less immediate sensor correction).
• Possible subsequent codes (less common) related to catalyst efficiency (P0420 or P0430) if downstream readings stay abnormal.

Note: Some test vehicles may not exhibit obvious drivability problems beyond the MIL; the key symptom is the diagnostic fault and slower sensor heating.

DIAGNOSTIC STEPS

Tools you’ll want:

• OBD-II scan tool with live data
• Digital multimeter (DMM) or oscilloscope for voltage/current and resistance tests
• Back-probe tool or pin-probe kit for O2 sensor connector
• Basic hand tools (wrenches, sockets) and O2 sensor wrench
• Safety gear (gloves, eye protection)

Step-by-step:

Confirm and document

• Read the code with your scanner and note any related codes (P0420, P0430, etc.).
• Check freeze-frame data to understand engine conditions when the code was stored.
• Confirm Bank 2 Sensor 2 is indeed the downstream sensor after the catalytic converter on the second bank.

Visual inspection

• Inspect the Bank 2 Sensor 2 harness and connector for signs of heat damage, oil/wax contamination, corrosion, pin bending, or loose connections.
• Check for exhaust system leaks upstream of the sensor that may skew readings (a leak can cause sensor readings to be inaccurate, though it won’t fix a heater fault).

Check fuses and power supply

• Locate the fuse(s) and/or fusible links for the O2 sensor heater circuits. Check that the fuses are intact.
• If a fuse is blown, replace it and re-test. If it blows again, there’s a short or a sensor issue.

Electrical tests on the sensor heater circuit

• With ignition on (engine off) or at key-on engine-run, back-probe the Bank 2 Sensor 2 heater circuit to verify voltage is present when it should be (often ~12V through the heater circuit; check service manual for exact pin). If voltage is absent, there’s a circuit power issue or a blown fuse/relay.
• Measure resistance of the O2 sensor heater element itself (two heater terminals). Typical healthy heater resistance is in the single-digit to low tens of ohms range (roughly 5–20 ohms, depending on sensor). If the resistance is infinite (open) or very low (short), the heater is faulty.
• If you have access to live data that shows the heater status, verify the heater status changes from OFF to ON as the sensor warms up. If the heater never engages, the circuit or sensor is suspect.

Inspect and test wiring and connector

• Look for damaged insulation, pin corrosion, bent pins, or misalignment in the connector.
• Disconnect the sensor, inspect the harness pins in the connector, clean if necessary (avoid exposing the sensor to cleaning sprays while connected).
• Reattach securely; corrosion or moisture can mimic a heater fault.

Decide on replacement vs repair

• If the heater circuit is consistently open/short and voltage is not reaching the heater, replace the sensor Bank 2 Sensor 2.
• If the heater shows proper resistance and voltage, recheck for intermittent faults or a PCM issue. If all wiring checks out, you may still need to replace the sensor due to internal heater failure not detectable by simple resistance tests.

Post-repair testing

• Clear codes and drive the vehicle under normal conditions to allow the exhaust to reach operating temperature.
• Use live data to confirm Bank 2 Sensor 2 is heating normally and reaching operating temperature quickly.
• Re-scan to ensure the P0155 code does not return.

Notes:

• When testing, avoid contaminating the oxygen sensor if you remove it (do not spray lubricants or cleaners on the sensor tip).
• If you replace the sensor, install with proper torque (often around 18–22 ft-lbs for many O2 sensors; check the service manual for Durango specifics) and apply anti-seize to the threads only if specified by the sensor manufacturer.

RELATED CODES

• Other P015x family codes (Bank 2 sensors) that can appear:
  • P0150: O2 sensor circuit malfunction (Bank 2 Sensor 1)
  • P0151: O2 sensor heater circuit malfunction (Bank 2 Sensor 1)
  • P0152: O2 sensor circuit high voltage (Bank 2 Sensor 1)
  • P0153: O2 sensor circuit low voltage (Bank 2 Sensor 1)
  • P0154: O2 sensor heater circuit malfunction (Bank 2 Sensor 1/2 variants vary by vehicle)
• Catalyst/engine monitoring related codes that may appear if downstream readings are consistently out of spec:
  • P0420: Catalyst System Efficiency Below Threshold (Bank 1)
  • P0430: Catalyst System Efficiency Below Threshold (Bank 2)

Note: Exact mappings for P015x can be vehicle-specific; refer to the Dodge Durango service information for your exact VIN if available.

REPAIR OPTIONS AND COSTS (2025 prices)

Prices are estimates for typical US-market labor and parts. Actual costs vary by region, shop rate, and parts choice (OEM Mopar vs. aftermarket).

• Option A: Replace Bank 2 Sensor 2 (O2 sensor)

  • Parts: Aftermarket sensor roughly $30–$120; OEM Mopar sensor roughly $100–$250.
  • Labor: About 0.6–1.2 hours depending on access (or 1–1.5 hours at some shops).
  • Estimated total: $90–$250 (aftermarket parts) or $260–$520 (OEM Mopar).

• Option B: Repair or replace wiring/connector for Bank 2 Sensor 2 heater circuit

  • Parts: Connector/wiring repair kit or harness section typically $20–$150.
  • Labor: About 0.5–2.0 hours depending on access and whether harness repair is straightforward or involves rerouting.
  • Estimated total: $100–$350.

• Option C: Fuse/relay replacement (if the issue is a blown fuse or relay)

  • Parts: Typically $0–$20.
  • Labor: Minimal; many shops won’t charge more than 0.5 hours.
  • Estimated total: $0–$60.

• Option D: PCM/ECU-related fault (rare)

  • Parts: PCM replacement or reprogramming can be $300–$1,200+ depending on whether a used or remanufactured unit is used and whether programming is needed.
  • Labor: 1–4 hours.
  • Estimated total: $400–$1,800.

• Notes on cost:

  • Replacing the sensor is typically the most cost-effective first step if the rest of the system checks out.
  • If the fault persists after sensor replacement, re-check wiring and seals; consider deeper diagnostics for PCM or catalytic issues.
  • Taxes and shop fees vary by location.

DIY vs PROFESSIONAL

• DIY-friendly scenarios:

  • You’re comfortable with locating and replacing a downstream O2 sensor.
  • You can safely disconnect the battery, access the sensor, remove the old sensor, and install the new one with the proper torque.
  • You can perform basic electrical tests (voltage, resistance) with a multimeter and interpret live data.

• When to go professional:

  • Access to the sensor is difficult (tight space, high exhaust components) or you don’t have the right tools (O2 sensor wrench, back-probing tools).
  • You’re not comfortable diagnosing electrical circuits or interpreting live data and freeze-frame data.
  • After sensor replacement, the code returns or there are related codes indicating catalytic or PCM issues.
  • If wiring or connector repairs are required in hard-to-reach areas, a professional shop is recommended.

• DIY considerations:

  • Use proper safety precautions (cool engine, protective gloves).
  • If you’re replacing the sensor, consider replacing both the upstream and downstream sensors if you’re already under the exhaust, but evaluate based on symptoms and cost.
  • After replacement, clear codes and test drive to verify the fix; recheck for future fault codes.

PREVENTION

• Regular sensor maintenance:
  • Use quality fuel and keep fuel system clean to minimize sensor contamination and corrosion.
  • Replace O2 sensors at manufacturer-recommended intervals or earlier if symptoms arise (downstream sensors often last longer; many owners see 60k–120k miles, depending on driving conditions).
• Address exhaust system issues promptly:
  • Fix any exhaust leaks upstream of Bank 2 Sensor 2, as leaks can affect readings and sensor operation.
• Protect electrical connections:
  • Ensure connectors are clean, dry, and free of corrosion; avoid exposure to water and salt at the connector.
• Quality parts:
  • Prefer OEM Mopar or high-quality aftermarket sensors designed for your Durango to reduce premature failure.
• Driving habits:
  • Occasional highway driving helps keep the exhaust system hot enough to prevent sensor deposits; cold-start heavy operation can stress sensors.
• Diagnostics:
  • If a sensor replacement does not fix P0155, re-check the entire circuit for possible shorts/opens and consider wiring harness wear near heat sources.

Recalls

• No recalls found in NHTSA database for this issue on 2021–2024 Dodge Durango based on the provided data.

Data limitations

• The guidance above is based on the provided NHTSA data indicating no owner complaints and no recalls for this model/year/issue combination. There are no official complaint statistics to cite for this specific code in this data. General diagnostic steps and repair costs reflect common industry practice for P0155 on modern Dodge/Chrysler vehicles and are augmented with typical Durango maintenance expectations. If you want the most precise diagnostic steps or component specs for your exact VIN, consult the factory service manual or a Dodge dealer.