WOMS
P code powertrain Medium severity

P1704 Digital TRS Failed to Transition States in KOEO / KOER

The OBD2 code P1704 indicates that the Transmission Range Sensor (TRS) has failed to transition between states during Key On Engine Off (KOEO) or Key On Engine Running (KOER) tests, suggesting a potential issue with the...

Definition

The OBD2 code P1704 indicates that the Transmission Range Sensor (TRS) has failed to transition between states during Key On Engine Off (KOEO) or Key On Engine Running (KOER) tests, suggesting a potential issue with the sensor or its circuit

Common causes

  • Faulty Transmission Range Sensor (TRS)
  • Poor electrical connections or wiring issues
  • Malfunctioning Powertrain Control Module (PCM)
  • Incorrectly adjusted or misaligned transmission components
  • Low transmission fluid levels or fluid contamination
  • Faulty or damaged transmission control solenoids
  • Software issues or updates needed in the PCM
  • Mechanical issues within the transmission itself

Common misdiagnoses

  • Faulty Transmission Control Module (TCM)
  • Defective Transmission Range Sensor (TRS)
  • Wiring or connector issues
  • Low transmission fluid levels
  • Faulty engine control module (ECM)
  • Incorrectly adjusted or misaligned shift linkage
  • Malfunctioning neutral safety switch
  • Transmission internal issues

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are other issues present

  2. 2. Inspect the Transmission Range Sensor

    Visual Inspection: Check the transmission range sensor for any physical damage, corrosion, or loose connections

  3. 3. Connector Check

    Ensure that the electrical connector to the sensor is secure and free of dirt or corrosion

  4. 4. Test the Transmission Range Sensor

    Resistance Check: Use a multimeter to measure the resistance of the sensor according to the manufacturer's specifications. Compare the readings to the expected values

  5. 5. Voltage Check

    With the ignition on, check the voltage at the sensor connector to ensure it is receiving the correct voltage

  6. 6. Inspect Wiring and Connectors

    Check the wiring harness and connectors for any signs of wear, fraying, or damage. Look for any shorts or open circuits that could affect the sensor's operation

  7. 7. Check for Ground Issues

    Ensure that the transmission range sensor has a good ground connection. A poor ground can lead to erratic sensor readings

  8. 8. Perform KOEO and KOER Tests

    Key On Engine Off (KOEO): With the engine off, turn the key to the "on" position and observe the sensor's readings. The sensor should transition states correctly (e.g., from Park to Reverse)

  9. 9. Key On Engine Running (KOER)

    Start the engine and repeat the observation. The sensor should still transition states correctly

  10. 10. Inspect the Transmission Control Module (TCM)

    If the sensor and wiring are in good condition, the issue may lie with the TCM. Check for any software updates or known issues with the TCM for your specific vehicle model

  11. 11. Check for Mechanical Issues

    Inspect the transmission for any mechanical issues that could affect the operation of the range sensor, such as linkage problems or internal transmission faults

  12. 12. Clear Codes and Test Drive

    After performing repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns

  13. 13. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission issues and OBD-II diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1704 code