U1102 – OBD-II DTC

OBD-II DTC U1102 – SCP (J1850) Invalid or Missing Data for Primary Id

DTC U1102 meaning

DTC U1102 refers to a diagnostic trouble code indicating “Invalid or Missing Data for Primary Id” 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 suggests that the vehicle’s control module is unable to receive valid data from another module, which may affect various vehicle functions.

DTC U1102 symptoms

Common symptoms associated with DTC U1102 may include:

• Illumination of the Check Engine Light (CEL)
• Loss of communication with certain vehicle modules
• Erratic or non-functional vehicle features (e.g., power windows, radio)
• Possible performance issues or reduced engine power

DTC U1102 causes

Several factors can lead to the occurrence of DTC U1102, including:

• Faulty or damaged wiring and connectors in the communication network
• Malfunctioning control modules (e.g., PCM, BCM)
• Corrupted software or firmware in one of the modules
• Issues with the vehicle’s battery or charging system
• Interference from aftermarket devices or modifications

DTC U1102 seriousness

The seriousness of DTC U1102 can vary depending on the specific vehicle and the systems affected. While it may not cause immediate safety concerns, it can lead to:

• Inability to use certain vehicle features
• Potential for further diagnostic trouble codes to appear
• Increased difficulty in diagnosing other issues due to communication failures

How to diagnose DTC U1102

To diagnose DTC U1102, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC U1102.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the wiring and connectors related to the affected modules for damage or corrosion.
4. Test the affected control modules for proper operation.
5. Verify the vehicle’s battery and charging system are functioning correctly.
6. Check for software updates or reprogramming needs for the control modules.

How to fix DTC U1102 step-by-step instructions

To fix DTC U1102, follow these steps:

1. Inspect and repair any damaged wiring or connectors in the communication network.
2. Replace any faulty control modules as necessary.
3. Update or reprogram the software in the affected modules if required.
4. Ensure the vehicle’s battery and charging system are in good condition.
5. Clear the DTC using an OBD-II scanner and test drive the vehicle to see if the code returns.

How to erase DTC U1102

To erase DTC U1102, 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 ensure the code does not reappear.

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