U1247 – SCP (J1850) Invalid or Missing Data for Primary Id

The ODBII code U1247 SCP (J1850) indicates that there is invalid or missing data for the primary identifier in the vehicle’s communication network, which may affect the operation of certain systems.

The severity of ODBII code U1247 is moderate.

Common Causes For: U1246 SCP (J1850) Invalid or Missing Data for Primary Id

• Faulty or damaged wiring/connectors
• Malfunctioning or disconnected sensors
• Issues with the vehicle’s communication network
• Faulty PCM (Powertrain Control Module)
• Corrupted or missing data in the vehicle’s software
• Low battery voltage or poor electrical connections
• Interference from aftermarket devices or modifications

Common misdiagnosis for U1247 SCP (J1850) Invalid or Missing Data for Primary Id

• Faulty wiring or connectors
• Defective control modules
• Incorrectly programmed or updated software
• Issues with the vehicle’s battery or charging system
• Problems with the communication network (CAN bus)
• Sensor malfunctions
• Intermittent electrical issues
• Grounding problems

Common Troubleshooting Steps

The OBD-II code U1247 indicates an issue with the SCP (Serial Communication Protocol) on the J1850 bus, specifically related to invalid or missing data for the primary ID. This can be caused by various factors, including communication issues between modules, wiring problems, or faulty components. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Addressing other codes may resolve the U1247 code.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors associated with the J1850 bus. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors on the modules that communicate over the J1850 bus.
• Check Battery Voltage: Ensure that the vehicle’s battery is fully charged and that the voltage is within the normal range (typically 12.4 to 12.6 volts). Low voltage can cause communication issues.
• Test the Communication Bus: Use a multimeter or an oscilloscope to check the voltage levels on the J1850 bus. You should see a specific voltage pattern when the vehicle is running.
• If you have access to a scan tool that can monitor live data, check for communication between modules.
• Inspect Modules: Identify the modules that communicate over the J1850 bus (e.g., PCM, BCM, ABS module). Check for any signs of failure or damage.
• If possible, perform a module reset or reprogramming if the module is suspected to be faulty.
• Check for Ground Issues: Ensure that all ground connections related to the communication network are secure and free of corrosion. Poor grounding can lead to communication failures.
• Look for Intermittent Issues: If the code is intermittent, try to replicate the conditions under which the code appears. This may help identify specific triggers.
• Perform a Network Test: If available, use a professional scan tool to perform a network test. This can help identify which module is not communicating properly.
• Check for Software Updates: Check if there are any software updates available for the vehicle’s modules. Sometimes, manufacturers release updates to fix communication issues.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the U1247 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known fixes.1
• Replace Faulty Components: If a specific module is identified as faulty, replace it. If wiring issues are found, repair or replace the damaged wiring.1
• Clear Codes and Test Drive: After performing repairs, clear the codes and take the vehicle for a test drive to see if the code returns.Conclusion If the issue persists after following these steps, it may be necessary to consult a professional technician with experience in automotive electronics and communication systems. They may have access to specialized diagnostic tools and resources to further diagnose the problem.