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P0155AcuraAcura MDX HubAll Acura P0155Medium Severity

P0155 on Acura MDX

O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Factory diagnostic protocol and troubleshooting wire for fault code P0155 specifically for the Acura MDX (2022–2026, 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)).

Verified OEM Telemetry & Field Repair Tree
Acura MDX2022–2026
Acura MDX
SUV3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
MDX SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$120 - $350 (DIY: $45 - $120)
Parts & Labor DIY
Check P0155 On Another Acura Model:
Diagnose P0155 on Specific MDX Model Year:

1. Symptoms of P0155 on Acura MDX

When the Engine Control Module (ECM/PCM) on your Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)) logs fault code P0155, drivers commonly observe:

Check Engine Light on immediately after cold start on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
Slightly increased cold-start emissions on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
No major driving performance issues once engine reaches full operating temperature on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
Acura MDX OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower dash assembly. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Acura MDX

Historical warranty claims and technical repair bulletins for Acura MDX point to the following failure distribution:

55%
Burnt-out heating element inside the Bank 2 Sensor 1 O2 sensor (Acura OEM Part)
25%
Blown O2 heater fuse in under-hood fuse block (Acura OEM Part)
12%
Corroded or broken heater power/ground wiring (Acura OEM Part)
8%
Faulty heater driver circuit in the PCM (Acura OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Acura MDX.

3. Step-by-Step DIY Repair Guide for Acura MDX

01
Check O2 Heater Fuse

Inspect the O2 HTR fuse in the engine fuse box with a test light or multimeter. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: Fuse Puller, Test Light
02
Test Heater Resistance on Bank 2 Sensor 1

Unplug the sensor connector and measure resistance between the two heater pins. An open circuit (infinite ohms / OL) confirms a dead internal heater. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: Digital Multimeter
03
Replace Bank 2 Upstream O2 Sensor

Remove faulty sensor and install a new OEM oxygen sensor with built-in heater. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: 22mm O2 Sensor Socket, Ratchet
04
Clear Codes and Perform Cold Start Verification

Clear DTCs and allow engine to cool down, then restart to confirm P0155 does not return. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Acura MDX (P0155)

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Direct-Fit Replacement Part

Acura MDX OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Acura MDX.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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Other Common Fault Codes on Acura MDX

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Acura MDX:

4. Acura MDX P0155 FAQs

What causes code P0155 to trigger on a Acura MDX?

On the Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)), P0155 is most frequently caused by Burnt-out heating element inside the Bank 2 Sensor 1 O2 sensor or Blown O2 heater fuse in under-hood fuse block.

Where is the OBD-II port located on my Acura MDX?

On the Acura MDX, the 16-pin DLC diagnostic connector is located Driver side lower dash assembly. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Acura MDX with code P0155?

Yes. The sensor will take longer to warm up, causing brief open-loop fuel delay on cold starts. Given that P0155 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.