U1254 – OBD-II DTC

OBD-II DTC U1254 – SCP (J1850) Invalid or Missing Data for Network Control

DTC U1254 meaning

DTC U1254 refers to a diagnostic trouble code indicating “Invalid or Missing Data for Network Control” in vehicles equipped with the On-Board Diagnostics II (OBD-II) system. This code is specifically related to the SCP (Serial Communication Protocol) using the J1850 communication standard. It signifies that the vehicle’s control modules are unable to communicate properly, often due to missing or corrupted data from one or more modules on the network.

DTC U1254 symptoms

Common symptoms associated with DTC U1254 may include:

• Illumination of the Check Engine Light (CEL)
• Loss of communication with certain control modules
• Erratic or non-functional vehicle features (e.g., power windows, radio)
• Performance issues such as stalling or poor acceleration
• Diagnostic tools unable to read data from the vehicle

DTC U1254 causes

Several factors can lead to the triggering of DTC U1254, including:

• Faulty or damaged wiring in the communication network
• Defective control modules (e.g., PCM, BCM)
• Corroded or loose connectors
• Software issues or bugs in the control modules
• Interference from aftermarket devices or modifications

DTC U1254 seriousness

DTC U1254 can be considered a moderate to serious issue. While it may not immediately affect the vehicle’s drivability, it can lead to further complications if left unaddressed. The inability to communicate with certain modules can result in the loss of critical vehicle functions, potentially compromising safety and performance.

How to diagnose DTC U1254

To diagnose DTC U1254, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1254.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the vehicle’s wiring and connectors related to the communication network for damage or corrosion.
4. Test the affected control modules for proper operation.
5. Verify the integrity of the SCP network by checking voltage and ground signals.
6. Consult the vehicle’s service manual for specific diagnostic procedures related to the control modules.

How to fix DTC U1254 step-by-step instructions

To fix DTC U1254, follow these steps:

1. Repair or replace any damaged wiring or connectors found during the diagnosis.
2. Replace any faulty control modules identified in the diagnostic process.
3. Update the software in the control modules if necessary.
4. Clear any stored trouble codes using an OBD-II scanner.
5. Perform a test drive to ensure the issue is resolved and the Check Engine Light does not reappear.

How to erase DTC U1254

To erase DTC U1254, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn the ignition key to the “On” position without starting the engine.
3. Access the scanner’s menu and select the option to clear or erase trouble codes.
4. Confirm the action and wait for the scanner to complete the process.
5. Disconnect the scanner and start the vehicle to verify that the Check Engine Light is off.

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