CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0127

DTC Code DTC Name
U0127 Lost Communication with Tire Pressure Monitor Module

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U0127 No communication from the tire pressure warning ECU and receiver continues.

  • Tire pressure warning ECU and receiver branch wire or connector

  • Power source circuit of tire pressure warning ECU and receiver

  • Tire pressure warning ECU and receiver

WIRING DIAGRAM

A01NI80E04

INSPECTION PROCEDURE

Note


  • Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the power switch off before inspecting CAN bus wires for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.

      Tech Tips

      If CAN MS bus DTC U1002 is output from the main body ECU (Intelligent tester display: Main Body), troubleshoot for U1002 and check for malfunctions in the CAN MS bus circuit.

      Result
      Result Proceed to
      U1002 is not output from main body ECU (Intelligent tester display: Main Body) A
      U1002 is output from main body ECU (Intelligent tester display: Main Body) B

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  2. CHECK FOR OPEN IN CAN BUS WIRES (TIRE PRESSURE WARNING ECU AND RECEIVER BRANCH WIRE)


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. A01NK5BE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Disconnect the tire pressure warning ECU and receiver connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      F118-3 (CANP) - F118-6 (CANN) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (TIRE PRESSURE WARNING ECU AND RECEIVER BRANCH WIRE)

    OK

  3. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)


    1. A01NK5BE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      F118-4 (GND) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)

    OK

  4. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Connect the cable to the negative (-) auxiliary battery terminal.

    2. Turn the power switch on (IG).

    3. A01NK5BE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      F118-1 (IG) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

    REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER Click here