DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:P1631

DTC Code DTC Name
P1631 Communication Error from ECM to VSC

DESCRIPTION

The ECM sends signals such as A/T information signals, dynamic radar cruise control operation signals and brake operation demand signals to the skid control ECU when the dynamic radar cruise control is operating. The ECM is the only component that has a function to store and output DTCs in the dynamic radar cruise control system. Therefore, if the skid control ECU detects a communication error from the ECM, it sends a malfunction signal back to the ECM.

DTC No. Detection Item DTC Detection Condition Trouble Area
P1631 Communication Error from ECM to VSC While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating (vehicle-to-vehicle distance control mode), if the ECM continuously receives a logical error signal from the skid control ECU for approximately 1 second or more.

  • Communication circuit

  • Skid control ECU (brake actuator assembly)*1

  • Skid control ECU (master cylinder solenoid)*2

  • ECM

*1: for Vacuum brake booster

*2: for Hydraulic brake booster

CAUTION / NOTICE / HINT

Note


  • Before replacing the ECM, refer to Service Bulletin.

  • First check the CAN communication system by following How to Proceed with Troubleshooting. After checking that there are no malfunctions in the CAN communication system, proceed with troubleshooting.

    Click here

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Using the GTS, check that the CAN communication system is functioning normally.

      OK
      CAN communication system is functioning normally.

      Tech Tips

      Refer to CAN Bus Check for the CAN communication system.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    GO TO CAN COMMUNICATION SYSTEM Click here

    OK

  2. REPLACE ECM


    1. Replace the ECM with a new one.

      for 1GR-FE: Click here

      for 1KD-FTV: Click here

      for 1GD-FTV: Click here

      for 2TR-FE: Click here

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR DTCs


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Clear the DTCs.

      Click here

    4. Make sure that the DTC detection conditions are met.

      Tech Tips

      If the detection conditions are not met, the malfunction cannot be detected.

    5. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC P1631 is not output A
      DTC P1631 is output B

    A

    END

    B

    REPLACE SKID CONTROL ECU for Vacuum Brake Booster: Click here
    REPLACE SKID CONTROL ECU for Hydraulic Brake Booster (for LHD): Click here
    REPLACE SKID CONTROL ECU for Hydraulic Brake Booster (for RHD): Click here