MazicBay Diagnostics
MAZICBAYDiagnostics
FTC Reader Disclosure: When you purchase or register through links on our site, we may earn an affiliate commission at no extra cost to you. Read our Editorial & Advertising Policy.

P0155 on Hyundai Ioniq 5

O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Factory diagnostic protocol and troubleshooting wire for fault code P0155 specifically for the Hyundai Ioniq 5 (2022–2026, Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP)).

Verified OEM Telemetry & Field Repair Tree
Hyundai Ioniq 52022–2026
Hyundai Ioniq 5
EVDual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Ioniq 5 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 Hyundai Model:
Diagnose P0155 on Specific Ioniq 5 Model Year:

1. Symptoms of P0155 on Hyundai Ioniq 5

When the Engine Control Module (ECM/PCM) on your Hyundai Ioniq 5 (Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP)) logs fault code P0155, drivers commonly observe:

Check Engine Light on immediately after cold start on Hyundai Ioniq 5 (Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP))
Slightly increased cold-start emissions on Hyundai Ioniq 5 (Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP))
No major driving performance issues once engine reaches full operating temperature on Hyundai Ioniq 5 (Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP))
Hyundai Ioniq 5 OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower dash bezel near steering base. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Hyundai Ioniq 5

Historical warranty claims and technical repair bulletins for Hyundai Ioniq 5 point to the following failure distribution:

55%
Burnt-out heating element inside the Bank 2 Sensor 1 O2 sensor (Hyundai OEM Part)
25%
Blown O2 heater fuse in under-hood fuse block (Hyundai OEM Part)
12%
Corroded or broken heater power/ground wiring (Hyundai OEM Part)
8%
Faulty heater driver circuit in the PCM (Hyundai OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Hyundai Ioniq 5.

3. Step-by-Step DIY Repair Guide for Hyundai Ioniq 5

01
Check O2 Heater Fuse

Inspect the O2 HTR fuse in the engine fuse box with a test light or multimeter. on the Hyundai Ioniq 5 equipped with Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP).

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 Hyundai Ioniq 5 equipped with Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP).

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 Hyundai Ioniq 5 equipped with Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP).

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 Hyundai Ioniq 5 equipped with Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP).

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

Equipment for Diagnosing Hyundai Ioniq 5 (P0155)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

Hyundai Ioniq 5 OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Hyundai Ioniq 5.

$45 – $95 Prime
Check Fitment on Amazon
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.

$29.99 Prime
View on Amazon
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.

Compare OEM & Aftermarket Replacement Sensors for Hyundai Ioniq 5Verified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
Find Parts on Amazon
* As an Amazon Associate, MazicBay earns from qualifying purchases. Prices & availability subject to change.

Other Common Fault Codes on Hyundai Ioniq 5

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Hyundai Ioniq 5:

4. Hyundai Ioniq 5 P0155 FAQs

What causes code P0155 to trigger on a Hyundai Ioniq 5?

On the Hyundai Ioniq 5 (Dual Motor AWD (320HP) / Single Motor RWD (225HP) / Ioniq 5 N (641HP)), 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 Hyundai Ioniq 5?

On the Hyundai Ioniq 5, the 16-pin DLC diagnostic connector is located Driver side lower dash bezel near steering base. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Hyundai Ioniq 5 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.