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Home >> Fiat >> 2017 >> 124 Spider Classica, Standard Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 ((Aw6R31 Automatic Transmission Control Module (TCM) - Electrical Diagnostics)) >> DTC Troubleshooting >> U1408-00 Implausible Brake Signal Received >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR THE PRESENCE OF ERRORS 
    1. Go to Key-OFF condition, then ON (engine off or on).
    2. Connect the diagnosis equipment and check for related errors.

      Are there any other errors?

      Yes 

      • Proceed as indicated by the diagnosis equipment to resolve other errors.
      • Go to Step  2.

      No 

      • Go to Step  2.
  2. CHECK TRANSMISSION CONTROL MODULE WIRING 
    1. Go to Key-OFF condition.
    2. Disconnect the Transmission Control Module and Anti-lock Brake System (ABS) Module connectors.
    3. Check whether the terminals of the Transmission Control Module and Anti-lock Brake System (ABS) Module are disconnected, damaged or corroded.

      Are terminals disconnected, damaged or corroded?

      Yes 

      • Repair or replace the connector or the terminals.
      • Go to Step  8.

      No 

      • Go to Step  3.
  3. CHECK POWER SUPPLY OF ANTI-LOCK BRAKE SYSTEM (ABS) MODULE 
    1. Ensure correct power supply of Anti-lock Brake System (ABS) Module.

      Is the power supply correct?

      Yes 

      • Go to Step  4.

      No 

      • Restore correct power supply.
      • Go to Step  8.
  4. CHECK POWER SUPPLY OF TRANSMISSION CONTROL MODULE 
    1. Check correct power supply of Automatic Transmission Module.

      Is the power supply correct?

      Yes 

      • Go to Step  5.

      No 

      • Restore correct power supply.
      • Go to Step  8.
  5. CHECK WIRING OF CAN NETWORK BETWEEN ANTI-LOCK BRAKE SYSTEM (ABS) MODULE AND TRANSMISSION CONTROL MODULE 
    1. Check for the presence of an open circuit on the wiring on CAN network between Anti-lock Brake System (ABS) Module and Transmission Control Module.

      Is there an open circuit on the CAN network?

      Yes 

      • Remove the open circuit.
      • Go to Step  8.

      No 

      • Go to Step  7.
  6. CHECK WIRING OF CAN NETWORK BETWEEN ANTI-LOCK BRAKE SYSTEM (ABS) MODULE AND TRANSMISSION CONTROL MODULE 
    1. Check correct insulation of the CAN network wiring between Anti-lock Brake System (ABS) Module and Transmission Control Module.

      Incorrect CAN network insulation?

      Yes 

      • Restore the correct insulation.
      • Go to Step  8.

      No 

      • Go to Step  7.
  7. CHECK CORRECT OPERATION OF THE ANTI-LOCK BRAKE SYSTEM (ABS) MODULE 
    1. Check correct operation of Anti-lock Brake System (ABS) Module.

      Is the Anti-lock Brake System (ABS) Module working correctly?

      Yes 

      • Go to Step  8.

      No 

      • Replace the Anti-lock Brake System (ABS) Module.
      • Go to Step  8.
  8. CHECK CORRECT OPERATION OF AUTOMATIC TRANSMISSION MODULE 
    1. Perform the Transmission Control Module error deletion procedure.
    2. Start the engine.
    3. Heat engine and gearbox.
    4. Drive the vehicle with automatic transmission selector in D position and ensure that the gear is shifted from the first to the sixth.
    5. Check whether there is a fault.

      Is the error still present?

      Yes 

      • Replace the Automatic Transmission Module.

      No 

      • End of diagnosis.