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U1900 Mercury Code - CAN Communication Bus Fault

- Code Popularity: 4,607 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC U1900 Mercury?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other 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
⚠ Does your Mercury have Safety Recalls? → Check here

How to Fix the DTC U1900 Mercury?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

This is typically a false/intermittent code. It can occur if:
Someone hooks up a scanner to the OBDII port while the ignition is on or while the engine is idling.
A trailer brake system is installed improperly/incorrectly on a truck with ABS (anti-lock brakes).

Search for U1900 Mercury Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1900 Mercury code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to 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.

What are Code Possible Symptoms?

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

Code U1900 Mercury 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.

OBDII Code U1900 Mercury - CAN Communication Bus Fault - AutoCodes.com
U1900 Mercury Code - CAN Communication Bus Fault

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Code U1900 Mercury comments

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