CAN Communication Bus Fault


Table of contents

U1900 FORD Possible Causes

  • Faulty / intermittent ignition switch connections
  • CAN Bus wiring intermittently open/shorted to power or ground
  • Faulty / intermittent connection at PCM
  • Faulty electrical connections at ABS Control Module
  • Faulty electrical connections at the instrument cluster
  • Poor connections at the trailer brake controller/trailer connector

How do I fix code U1900 FORD?

  Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.

Tech Notes

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Cost of diagnosing the U1900 FORD code

  The cost of diagnosing the U1900 FORD code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

When is the code detected

  When the PCM, Brake Controller and Instrument Cluster are unable to communicate with each other at any time while the ignition switch is turned to the “Run” position, code U1900 sets in memory.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Amber ABS (Anti-lock Brakes) Light ON
  • Wrench Light On

U1900 FORD Description

  The Anti-ock Brakes System (ABS) module, the Powertrain Control Module (PCM), and the instrument cluster communicate over the Controller Area Network (CAN) Bus. This is a high-speed bus communication system and is not fault tolerant, which means any type of intermittent/loose connection between these 3 controllers will cause communication to stop. When the PCM, ABS module and instrument cluster are unable to communicate with each other at any time while the ignition switch is turned on, code U1900 will set.

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