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DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0129: Lost Communication with Brake System Control Module; DTC U0293: Lost Communication with HV ECU [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. RECONFIRM DTC OUTPUT 
    1. Reconfirm DTCs.

      HINT: 

      If the power management control ECU outputs only DTC U0129, troubleshoot DTC U0129 and check the branch circuit of sub bus 15.

      Result

      Result Proceed to
      The power management control ECU outputs DTC U0129 and other DTCs.
      (Techstream display: Hybrid Control)      		 A
      The power management control ECU outputs only DTC U0129.
      (Techstream display: Hybrid Control)      		 B

    B → See step   17 

    A: Go to next step 

  2. CHECK SUB BUS 15 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Measure the resistance according to the value(s) in the table below.
      GTY415451Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      H2-31 (CA3P) - H2-30 (CA3N) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω Below 54 Ω: Short circuit between bus lines
      70 Ω or higher: Open circuit in a main bus line
      H2-31 (CA3P) - H2-4 (E12) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANH ground short
      H2-30 (CA3N) - H2-4 (E12) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANL ground short
      H2-31 (CA3P) - H2-7 (AM21) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      H2-30 (CA3N) - H2-7 (AM21) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANL +B short
      TEXT IN ILLUSTRATION

      *a Component with harness connected
      (Power Management Control ECU)

      HINT: 

      • When the values are as specified, clear and recheck for DTCs. When no DTCs are output, check for malfunctions such as damage or improper connection of the relevant connectors.
      • If DTCs are output although the bus circuit is normal and DTCs were cleared, replace the power management control ECU.

      Result

      Result Proceed to
      OK A
      NG (Open circuit in CAN main bus line) B
      NG (Short circuit between bus lines) C
      • NG (Ground short)
      • NG (+B short)
      		 D

    B → See step   3 

    C → See step   6 

    D → See step   10 

    A → See step   14 

  3. CHECK FOR OPEN IN SUB BUS 15 MAIN LINES (POWER MANAGEMENT CONTROL ECU) 
    1. Disconnect the H2 power management control ECU connector.
      GTY415467Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H2-31 (CA3P) - H2-30 (CA3N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Power Management Control ECU)

    NG → See step   4 

    OK → See step   14 

  4. CHECK FOR OPEN IN SUB BUS 15 MAIN LINES (CAN NO. 1 J/C) 
    1. Reconnect the H2 power management control ECU connector.
    2. Disconnect the A62 CAN No. 1 junction connector.
      GTY413730Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      A62-2 (CANH) - A62-5 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω ECM
      A62-3 (CANH) - A62-6 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Power management control ECU
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to CAN No. 1 Junction Connector)
      *b to ECM
      *c to Power Management Control ECU

      Result

      Result Proceed to
      OK A
      NG (Open circuit in power management control ECU CAN main bus line) B
      NG (Open circuit in ECM CAN main bus line) C

    B → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - CAN NO. 1 J/C) 

    C → See step   5 

    A → REPLACE CAN NO. 1 JUNCTION CONNECTOR 

  5. CHECK FOR OPEN IN SUB BUS 15 MAIN LINES (ECM - CAN NO. 1 J/C) 
    1. Reconnect the A62 CAN No. 1 junction connector.
    2. Disconnect the A22 ECM connector.
      GTY407238Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A22-12 (CANP) - A22-25 (CANN) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM - CAN NO. 1 J/C) 

    OK → See step   15 

  6. CHECK FOR SHORT IN SUB BUS 15 LINES (POWER MANAGEMENT CONTROL ECU) 
    1. Disconnect the H2 power management control ECU connector.
      GTY415467Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H2-31 (CA3P) - H2-30 (CA3N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Power Management Control ECU)

    NG → See step   7 

    OK → See step   14 

  7. CHECK FOR SHORT IN SUB BUS 15 LINES (CAN NO. 1 J/C) 
    1. Reconnect the H2 power management control ECU connector.
    2. Disconnect the A62 CAN No. 1 junction connector.
      GTY419804Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      A62-1 (CANH) - A62-4 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Brake booster with master cylinder assembly (skid control ECU)
      A62-2 (CANH) - A62-5 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω ECM
      A62-3 (CANH) - A62-6 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Power management control ECU
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to CAN No. 1 Junction Connector)
      *b to Brake Booster with Master Cylinder Assembly (Skid Control ECU)
      *c to ECM
      *d to Power Management Control ECU

      Result

      Result Proceed to
      OK A
      NG (Short circuit between bus lines in power management control ECU CAN main bus line) B
      NG (Short circuit between bus lines in ECM CAN main bus line) C
      NG (Short circuit between bus lines in brake booster with master cylinder assembly (skid control ECU) CAN branch line) D

    B → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - CAN NO. 1 J/C) 

    C → See step   8 

    D → See step   9 

    A → REPLACE CAN NO. 1 JUNCTION CONNECTOR 

  8. CHECK FOR SHORT IN SUB BUS 15 LINES (ECM - CAN NO. 1 J/C) 
    1. Reconnect the A62 CAN No. 1 junction connector.
    2. Disconnect the A22 ECM connector.
      GTY407238Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A22-12 (CANP) - A22-25 (CANN) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM - CAN NO. 1 J/C) 

    OK → See step   15 

  9. CHECK FOR SHORT IN SUB BUS 15 LINES (BRAKE BOOSTER WITH MASTER CYLINDER - CAN NO. 1 J/C) 
    1. Reconnect the A62 CAN No. 1 junction connector.
    2. Disconnect the A24 brake booster with master cylinder assembly (skid control ECU) connector.
      GTY409773Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A24-35 (CA2H) - A24-34 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Brake Booster with Master Cylinder Assembly (Skid Control ECU))

    NG → REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) 

    OK → See step   16 

  10. CHECK FOR SHORT IN SUB BUS 15 LINES (CAN NO. 1 J/C) 
    1. Disconnect the A62 CAN No. 1 junction connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY406732Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition Purpose Connected to
      A62-1 (CANH) - H29-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short Brake booster with master cylinder assembly (skid control ECU)
      A62-4 (CANL) - H29-4 (CG)
      A62-2 (CANH) - H29-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short ECM
      A62-5 (CANL) - H29-4 (CG)
      A62-3 (CANH) - H29-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short Power management control ECU
      A62-6 (CANL) - H29-4 (CG)
      A62-1 (CANH) - H29-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short Brake booster with master cylinder assembly (skid control ECU)
      A62-4 (CANL) - H29-16 (BAT)
      A62-2 (CANH) - H29-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short ECM
      A62-5 (CANL) - H29-16 (BAT)
      A62-3 (CANH) - H29-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short Power management control ECU
      A62-6 (CANL) - H29-16 (BAT)
      TEXT IN ILLUSTRATION

      *1 DLC3 - -
      *a Front view of wire harness connector
      (to CAN No. 1 Junction Connector)      		 *b to Brake Booster with Master Cylinder Assembly (Skid Control ECU)
      *c to ECM *d to Power Management Control ECU

      HINT: 

      • It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 15 inspection.
      • Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 15 inspection.

      Result

      Result Proceed to
      OK A
      • NG (Ground short in power management control ECU CAN main bus line)
      • NG (+B short in power management control ECU CAN main bus line)
      		 B
      • NG (Ground short in ECM CAN main bus line)
      • NG (+B short in ECM CAN main bus line)
      		 C
      • NG (Ground short in brake booster with master cylinder assembly (skid control ECU) CAN branch line)
      • NG (+B short in brake booster with master cylinder assembly (skid control ECU) CAN branch line)
      		 D

    B → See step   11 

    C → See step   12 

    D → See step   13 

    A → REPLACE CAN NO. 1 JUNCTION CONNECTOR 

  11. CHECK FOR SHORT IN SUB BUS 15 LINES (POWER MANAGEMENT CONTROL ECU - CAN NO. 1 J/C) 
    1. Disconnect the H2 power management control ECU connector.
      GTY415470Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Purpose Specified Condition
      H2-31 (CA3P) - H2-4 (E12) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH ground short 200 Ω or higher
      H2-30 (CA3N) - H2-4 (E12)
      H2-31 (CA3P) - H2-7 (AM21) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH +B short 6 kΩ or higher
      H2-30 (CA3N) - H2-7 (AM21)

      HINT: 

      • It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 15 inspection.
      • Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 15 inspection.
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to Power Management Control ECU)

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - CAN NO. 1 J/C) 

    OK → See step   14 

  12. CHECK FOR SHORT IN SUB BUS 15 LINES (ECM - CAN NO. 1 J/C) 
    1. Disconnect the A22 ECM connector.
      GTY419264Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Purpose Specified Condition
      A22-12 (CANP) - D24-16 (E1) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH ground short 200 Ω or higher
      A22-25 (CANN) - D24-16 (E1)
      A22-12 (CANP) - A22-1 (BATT) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH +B short 6 kΩ or higher
      A22-25 (CANN) - A22-1 (BATT)

      HINT: 

      • It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 15 inspection.
      • Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 15 inspection.
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)

    NG → REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM - CAN NO. 1 J/C) 

    OK → See step   15 

  13. CHECK FOR SHORT IN SUB BUS 15 LINES (BRAKE BOOSTER WITH MASTER CYLINDER - CAN NO. 1 J/C) 
    1. Disconnect the A24 brake booster with master cylinder assembly (skid control ECU) connector.
      GTY399812Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Purpose Specified Condition
      A24-35 (CA2H) - A24-28 (GND) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH ground short 200 Ω or higher
      A24-34 (CA2L) - A24-28 (GND)
      A24-35 (CA2H) - A24-15 (BS) Cable disconnected from negative (-) auxiliary battery terminal Inspection for CANH +B short 6 kΩ or higher
      A24-34 (CA2L) - A24-15 (BS)

      HINT: 

      • It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 15 inspection.
      • Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 15 inspection.
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Brake Booster with Master Cylinder Assembly (Skid Control ECU))

    NG → REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) 

    OK → See step   16 

  14. REPLACE POWER MANAGEMENT CONTROL ECU. Refer to  REMOVAL [08/2013 - ] 
  15. REPLACE ECM. Refer to  REMOVAL [08/2013 - ] 
  16. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [08/2013 - ] 
  17. GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC. Refer to  DTC U0129: Lost Communication with Brake System Control Module [08/2013 - ]  
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