U1055 – OBD-II DTC

OBD-II DTC U1055 – SCP (J1850) Invalid or Missing Data for Primary Id

DTC U1055 meaning

DTC U1055 refers to a communication error within the vehicle’s network, specifically indicating “Invalid or Missing Data for Primary Id.” This code is associated with the SCP (Standard Corporate Protocol) communication protocol, which is used in some General Motors vehicles. The error suggests that the vehicle’s control modules are unable to receive or interpret the necessary data from a primary module, leading to potential issues in vehicle performance and diagnostics.

DTC U1055 symptoms

Common symptoms associated with DTC U1055 may include:

• Illumination of the check engine light
• Loss of communication with certain modules
• Erratic behavior of vehicle systems
• Inability to read data from the vehicle’s diagnostic system
• Potential performance issues, such as stalling or reduced power

DTC U1055 causes

Several factors can lead to the occurrence of DTC U1055, including:

• Faulty wiring or connectors in the communication network
• Defective control modules
• Corrosion or damage to the connectors
• Software issues within the control modules
• Interference from aftermarket devices or modifications

DTC U1055 seriousness

The seriousness of DTC U1055 can vary depending on the specific symptoms and the vehicle’s overall condition. While it may not immediately affect drivability, it can lead to more significant issues if left unaddressed. It is essential to diagnose and resolve the underlying problem to ensure proper vehicle operation and prevent further complications.

How to diagnose DTC U1055

To diagnose DTC U1055, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the DTC.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the wiring and connectors related to the affected control modules.
4. Test the affected control modules for proper operation.
5. Verify the integrity of the SCP communication network.
6. Check for software updates or reprogramming needs for the control modules.

How to fix DTC U1055 step-by-step instructions

To fix DTC U1055, follow these step-by-step instructions:

1. Perform a visual inspection of the wiring and connectors for damage or corrosion.
2. Repair or replace any damaged wiring or connectors.
3. Test the affected control modules to ensure they are functioning correctly.
4. If necessary, reprogram or update the software of the control modules.
5. Clear the DTC using an OBD-II scanner.
6. Test drive the vehicle to ensure the code does not return.

How to erase DTC U1055

To erase DTC U1055, 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 code has been cleared.

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