U1900 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
First diagnose U1900 code
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 terminals.
U1900 Tech NotesThis 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).
Cost of diagnosing the U1900 code
Labor: 1.0The cost of diagnosing the U1900 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 U1900 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.
U1900 Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Amber ABS (Anti-lock Brakes) Light ON
- Wrench Light On
U1900 DescriptionThe 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.
U1900 More InformationNeed more information on how to fix the U1900 code?
Get Access to Factory Service Manuals
U1900 Information for specific makes
Need more help?Get the U1900 code diagnosed by a professional: Find a repair shop in your area
U1900 CommentsHelp us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the U1900 code? Have you replaced any parts?
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