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.

U0104 on Hyundai Elantra

Lost Communication with Cruise Control Module

Factory diagnostic protocol and troubleshooting wire for fault code U0104 specifically for the Hyundai Elantra (2020–2026, 2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP)).

Verified OEM Telemetry & Field Repair Tree
Hyundai Elantra2020–2026
Hyundai Elantra
Sedan2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Elantra SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Not Recommended
Low urgency level
Est. Repair Cost
$100 - $450 (DIY: $0 - $150)
Parts & Labor DIY
Check U0104 On Another Hyundai Model:
Diagnose U0104 on Specific Elantra Model Year:

1. Symptoms of U0104 on Hyundai Elantra

When the Engine Control Module (ECM/PCM) on your Hyundai Elantra (2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP)) logs fault code U0104, drivers commonly observe:

Adaptive Cruise Control (ACC) disabled on Hyundai Elantra (2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP))
Pre-Collision System warning light on on Hyundai Elantra (2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP))
Check Engine Light on on Hyundai Elantra (2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP))
Hyundai Elantra OBD-II Port Location
The 16-pin diagnostic connector is located Behind fuse cover panel on driver left knee dashboard. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Hyundai Elantra

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

55%
Blocked or dirty front radar sensor in grille/bumper (Hyundai OEM Part)
25%
Blown radar module fuse (Hyundai OEM Part)
12%
Faulty radar cruise control module (Hyundai OEM Part)
8%
Misaligned radar sensor following minor bumper bump (Hyundai OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Hyundai Elantra.

3. Step-by-Step DIY Repair Guide for Hyundai Elantra

01
Clean Front Radar Sensor in Grille

Clean snow, ice, mud, or dead bugs off front radar emblem. on the Hyundai Elantra equipped with 2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP).

Required Tool: Microfiber Towel
02
Check ACC / Radar Fuse

Verify power feed to radar sensor. on the Hyundai Elantra equipped with 2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP).

Required Tool: Test Light
03
Perform Radar Aiming Calibration

Execute optical/radar alignment procedure if bumper was removed. on the Hyundai Elantra equipped with 2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP).

Required Tool: Calibration Target, Scan Tool
04
Clear Trouble Codes

Clear DTCs and test cruise on highway. on the Hyundai Elantra equipped with 2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP).

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

Equipment for Diagnosing Hyundai Elantra (U0104)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

Hyundai Elantra OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

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

$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 ElantraVerified 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 Elantra

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

4. Hyundai Elantra U0104 FAQs

What causes code U0104 to trigger on a Hyundai Elantra?

On the Hyundai Elantra (2.0L Smartstream (147HP) / 1.6L Turbo (N Line 201HP) / 2.0L Turbo (Elantra N 276HP)), U0104 is most frequently caused by Blocked or dirty front radar sensor in grille/bumper or Blown radar module fuse.

Where is the OBD-II port located on my Hyundai Elantra?

On the Hyundai Elantra, the 16-pin DLC diagnostic connector is located Behind fuse cover panel on driver left knee dashboard. 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 Elantra with code U0104?

Yes. Normal driving is unaffected, but Adaptive Cruise Control will not engage. Given that U0104 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.