WOMS
U code network Medium severity

U1308 SCP (J1850) Invalid or Missing Data for Function Read Engine Torque

The OBD2 code U1308 SCP (J1850) Invalid or Missing Data for Function Read Engine Torque indicates that the vehicle's communication network is not receiving valid data regarding the engine torque, which may be due to a...

Definition

The OBD2 code U1308 SCP (J1850) Invalid or Missing Data for Function Read Engine Torque indicates that the vehicle's communication network is not receiving valid data regarding the engine torque, which may be due to a malfunction in the engine control module or issues with the data bus

Common causes

  • Faulty Engine Control Module (ECM)
  • Poor or damaged wiring/connectors
  • Malfunctioning sensors (e.g., throttle position sensor, mass air flow sensor)
  • Communication issues between modules
  • Corrupted data in the vehicle network
  • Low battery voltage or poor ground connections
  • Faulty or incompatible aftermarket components
  • Software issues or outdated firmware in the ECM

Common misdiagnoses

  • Faulty Engine Control Module (ECM)
  • Bad wiring or connectors
  • Faulty sensors (e.g., throttle position sensor, mass airflow sensor)
  • Communication issues in the CAN bus
  • Incorrectly calibrated or programmed ECM
  • Faulty transmission control module (TCM)
  • Issues with the vehicle's battery or charging system
  • Grounding problems
  • Faulty or corroded connectors in the data link
  • Software glitches or updates needed in the ECM

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Sometimes, related codes can provide more context for the issue

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors related to the engine control module (ECM) and any other modules that communicate over the SCP (J1850) bus

  3. 3. Look for Damage

    Look for frayed wires, corrosion, or loose connections that could disrupt communication

  4. 4. Check the Battery and Ground Connections

    Ensure that the battery is fully charged and that all ground connections are clean and secure. Poor grounding can lead to communication issues

  5. 5. Test the Communication Bus

    Use a scan tool to monitor the data on the SCP (J1850) bus. Check for any irregularities in the data stream

  6. 6. If possible, use an oscilloscope to check the signal integrity on the bus

  7. 7. Inspect the Engine Control Module (ECM)

    Ensure that the ECM is functioning properly. If the ECM is faulty, it may not send or receive data correctly

  8. 8. Check for any software updates or reprogramming that may be required for the ECM

  9. 9. Check for Intermittent Issues

    Sometimes, the issue may be intermittent. Pay attention to when the code appears (e.g., during specific driving conditions) and try to replicate the scenario

  10. 10. Look for Faulty Sensors

    The engine torque reading may depend on various sensors (e.g., throttle position sensor, mass airflow sensor). Check these sensors for proper operation and signal output

  11. 11. Perform a System Reset

    Clear the trouble codes and see if the code returns after a test drive. This can help determine if the issue is persistent or if it was a temporary glitch

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to your vehicle make and model that might address this specific code or related communication issues

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in your vehicle's make and model.Conclusion Troubleshooting OBD-II code U1308 involves a systematic approach to check for communication issues, inspect wiring and connections, and ensure that all related components are functioning correctly. By following these steps, you can narrow down the potential causes and work towards a resolution