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U0104RAMRAM 2500 HubAll RAM U0104Low Severity

U0104 on RAM 2500

Lost Communication with Cruise Control Module

Factory diagnostic protocol and troubleshooting wire for fault code U0104 specifically for the RAM 2500 (2020–2026, 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP)).

Verified OEM Telemetry & Field Repair Tree
RAM 25002020–2026
RAM 2500
Truck6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
2500 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 RAM Model:
Diagnose U0104 on Specific 2500 Model Year:

1. Symptoms of U0104 on RAM 2500

When the Engine Control Module (ECM/PCM) on your RAM 2500 (6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP)) logs fault code U0104, drivers commonly observe:

Adaptive Cruise Control (ACC) disabled on RAM 2500 (6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP))
Pre-Collision System warning light on on RAM 2500 (6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP))
Check Engine Light on on RAM 2500 (6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP))
RAM 2500 OBD-II Port Location
The 16-pin diagnostic connector is located Driver footwell below steering column near parking brake. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on RAM 2500

Historical warranty claims and technical repair bulletins for RAM 2500 point to the following failure distribution:

55%
Blocked or dirty front radar sensor in grille/bumper (RAM OEM Part)
25%
Blown radar module fuse (RAM OEM Part)
12%
Faulty radar cruise control module (RAM OEM Part)
8%
Misaligned radar sensor following minor bumper bump (RAM OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for RAM 2500.

3. Step-by-Step DIY Repair Guide for RAM 2500

01
Clean Front Radar Sensor in Grille

Clean snow, ice, mud, or dead bugs off front radar emblem. on the RAM 2500 equipped with 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP).

Required Tool: Microfiber Towel
02
Check ACC / Radar Fuse

Verify power feed to radar sensor. on the RAM 2500 equipped with 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP).

Required Tool: Test Light
03
Perform Radar Aiming Calibration

Execute optical/radar alignment procedure if bumper was removed. on the RAM 2500 equipped with 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP).

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

Clear DTCs and test cruise on highway. on the RAM 2500 equipped with 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP).

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

Equipment for Diagnosing RAM 2500 (U0104)

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Direct-Fit Replacement Part

RAM 2500 OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for RAM 2500.

$45 – $95 Prime
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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.

$29.99 Prime
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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.

Compare OEM & Aftermarket Replacement Sensors for RAM 2500Verified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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Other Common Fault Codes on RAM 2500

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the RAM 2500:

4. RAM 2500 U0104 FAQs

What causes code U0104 to trigger on a RAM 2500?

On the RAM 2500 (6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP)), 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 RAM 2500?

On the RAM 2500, the 16-pin DLC diagnostic connector is located Driver footwell below steering column near parking brake. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my RAM 2500 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.