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U0073 on RAM: Symptoms, Causes & Fix

Control Module Communication Bus A Off

Official technical diagnostic wire for fault code U0073 specifically affecting RAM vehicles (1500, 2500, 3500, TRX).

Sensor Voltage Ref
0.1V – 5.0V Ref
RAM Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$150 - $850 (DIY: $40 - $200)
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your RAM Model for U0073:

5 Models Available
RAM 15002020–2026
RAM 1500Truck • 3.0L Hurricane Twin-Turbo I6 (420HP/540HP) / 5.7L HEMI V8 eTorque / 3.6L Pentastar
U0073 Fix & DLC Location
RAM 25002020–2026
RAM 2500Truck • 6.7L Cummins Turbo-Diesel I6 (420HP / 1,075 lb-ft) / 6.4L HEMI V8 (410HP)
U0073 Fix & DLC Location
RAM ProMaster2020–2026
RAM ProMasterVan • 3.6L Pentastar V6 (280HP) / 3.0L EcoDiesel (174HP)
U0073 Fix & DLC Location
RAM 35002020–2026
RAM 3500Truck • 6.7L High-Output Cummins Turbo-Diesel (420HP / 1,075 lb-ft torque / Dual Rear Wheel)
U0073 Fix & DLC Location
RAM 1500 TRX2021–2024
RAM 1500 TRXTruck • 6.2L Supercharged HEMI V8 (702HP / 650 lb-ft / Bilstein Black Hawk e2)
U0073 Fix & DLC Location

1. Common Symptoms on RAM Vehicles

When RAM Engine Control Modules (ECM) trigger fault code U0073, drivers typically report:

StabiliTrak / Traction / ABS / Engine warning lights lit on RAM Powertrains
Transmission shifting harshly or refusing to shift out of 2nd gear on RAM Powertrains
No communication with TCM, ABS, or BCM on RAM Powertrains
Engine may refuse to crank on RAM Powertrains

2. Root Causes on RAM Engines

Historical diagnostic claims across RAM engines point to the following failure distribution:

55%
Loose or corroded ground connection on transmission or frame (RAM OEM Part)
25%
Faulty Transmission Control Module (TCM) or ABS module pulling bus down (RAM OEM Part)
12%
Poor connection at large body-to-chassis pass-through harness connector (RAM OEM Part)
8%
Aftermarket accessory (remote starter, GPS tracker, cheap OBD scanner) broadcasting invalid data (RAM OEM Part)

3. Step-by-Step Fix Protocol for RAM

01
Unplug All Aftermarket OBD-II Devices

Remove any aftermarket insurance dongles, GPS trackers, or scan tools plugged into the DLC port. on RAM engines.

Required Tool: None
02
Inspect Frame and Transmission Ground Straps

Inspect braided ground straps on engine and transmission. Clean all contact surfaces to bare metal. on RAM engines.

Required Tool: Wire Brush, Sockets
03
Perform Full Vehicle Network Topology Scan

Scan all modules on vehicle. Note which modules are online and which are offline to pinpoint the break in the network daisy-chain. on RAM engines.

Required Tool: Full-System OBD-II Diagnostic Scanner
04
Check Terminating Resistance (60 Ohms)

Verify 60 ohms across Pins 6 and 14 with battery disconnected. on RAM engines.

Required Tool: Multimeter
05
Clear All System DTCs & Road Test

Clear DTCs from all modules and road test to verify error-free network transmission. on RAM engines.

Required Tool: Scan Tool
Recommended Parts & Testing Tools

Equipment for Diagnosing RAM (U0073)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

RAM OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

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

$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 RAMVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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4. RAM U0073 Frequently Asked Questions

What does code U0073 mean on a RAM?

On RAM vehicles, U0073 indicates that the Engine Control Module (ECM) detected control module communication bus a off. This typically points to Loose or corroded ground connection on transmission or frame or Faulty Transmission Control Module (TCM) or ABS module pulling bus down.

Can I continue driving my RAM with code U0073?

No. Bus is shut down due to excessive transmission errors, leaving vehicle in unpredictable limp mode. Because this code carries a Critical severity rating on RAM powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code U0073 on a RAM?

Estimated DIY parts cost ranges from $150 - $850 (DIY: $40 - $200), while professional shop repairs at an authorized RAM dealership or independent specialist typically range from $180 to $380 including diagnostic labor.