Engine-Codes - Generic - U1000

U1000 Code - CAN Communication Line Signal Malfunction

- Code Popularity: 36,809 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC U1000?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Controller Area Network (CAN) communication harness is open or shorted
  • Faulty Engine Control Module (ECM)
  • Poor harness ground connection.

Code Tech Notes





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How to Fix the DTC U1000?

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 pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the U1000 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the U1000 Code Mean?

The Controller Area Network (CAN) is a standard bus system in vehicles that enables the connection of automotive devices without the need for a host computer. The exchange of operating information and commands among devices is facilitated by pre-programmed information about the required message exchange on the serial data circuits. Communication is carried out using two dedicated wires, known as CAN high and CAN low, with both lines carrying 2.5V when the CAN bus is in idle mode. During the transmission of data bits, the CAN high line increases to 3.75V while the CAN low drops to 1.25V, creating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when the Engine Control Module (ECM) is not transmitting or receiving CAN communication signals for 2 seconds or more.

U1000 Code - CAN Communication Line Signal Malfunction

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Code U1000 Information for Specific Makes

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