Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001GHB5
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 03/2019]
Title: 2ZR-FAE (ENGINE CONTROL): SFI SYSTEM: U011B; Lost Communication with Rocker Arm Control Module "A"; 2020 MY Corolla [01/2019 - 03/2019]

DTC

U011B

Lost Communication with Rocker Arm Control Module "A"

DESCRIPTION

The ECM and continuously variable valve lift controller assembly communicate via the CAN communication system.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

U011B

Lost Communication with Rocker Arm Control Module "A"

CAN communication stops (1 trip detection logic).

  • CAN communication circuit
  • Continuously variable valve lift controller assembly
  • ECM

Comes on

DTC stored

MONITOR DESCRIPTION

When between the ECM and the continuously variable valve lift controller assembly is a malfunction in the CAN communication, this DTC is stored and the MIL is illuminated.

MONITOR STRATEGY

Related DTCs

U011B: Lost communication with rocker arm control module verify communication

Required Sensors/Components (Main)

Continuously variable valve lift controller assembly

ECM

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.19 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

All of the following conditions are met

-

Battery voltage

10.5 V or higher

Ignition switch

ON

Command to rocker arm control module power

On

Rocker arm control module power supply line low voltage fail (P104A)

Not detected

Starter

Off

TYPICAL MALFUNCTION THRESHOLDS

Communication signal

Lost communication with rocker arm control module

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Start the engine and warm it up.
  3. Turn the Techstream on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the ignition switch off and wait for at least 30 seconds.
  6. Start the engine and idle it for 20 seconds.
  7. Turn the Techstream on.
  8. Clear the DTCs.
  9. Turn the ignition switch off and wait for at least 30 seconds.
  10. Start the engine and idle it for 20 seconds.
  11. Turn the ignition switch off and wait for at least 30 seconds.
  12. Turn the ignition switch to ON.
  13. Turn the Techstream on.
  14. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
  15. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  16. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  17. Input the DTC: U011B.
  18. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL

    • DTC judgment completed
    • System normal

    ABNORMAL

    • DTC judgment completed
    • System abnormal

    INCOMPLETE

    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
  19. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs.

    Click here 2020 MY Corolla [01/2019 - 03/2019]; 2ZR-FAE (ENGINE CONTROL): SFI SYSTEM: DTC CHECK / CLEAR

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When one of the following DTCs is output and the MIL is illuminated, actuator position learning is performed during the next trip. After the system returns to normal, actuator position learning is performed during the next trip and the MIL remains illuminated until learning is complete.

    Actuator position learning is performed when these DTCs are output.

    P1049, P104A, P1055, P2646, P2647, P2648, P2649, P264A, U011B

  • Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

  • When there is no power (+B) supplied to the continuously variable valve lift controller assembly, DTC U011B is stored. Also, if the SDWN circuit is open, power supply is stopped and DTC U011B is stored.
  • After performing repairs, perform the following procedure and check that DTCs are not output again.
  • After using the Techstream to perform minimum valve lift learning, keep the engine idling for 30 seconds to complete learning. Otherwise, the VALVEMATIC system may not operate normally, causing poor acceleration, etc.
  • Read Freeze Frame Data using the Techstream. The ECM records vehicle and driving condition information as Freeze Frame Data the moment a DTC is stored. When troubleshooting, Freeze Frame Data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF CONTINUOUSLY VARIABLE VALVE LIFT CONTROLLER ASSEMBLY)

(a) Disconnect the continuously variable valve lift controller assembly connector.

*a

Front view of wire harness connector

(to Continuously Variable Valve Lift Controller Assembly)

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

C116-1 (+B) - Body ground

Ignition switch ON

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (CONTINUOUSLY VARIABLE VALVE LIFT CONTROLLER ASSEMBLY - BATTERY)

OK

2.

CHECK HARNESS AND CONNECTOR (CONTINUOUSLY VARIABLE VALVE LIFT CONTROLLER ASSEMBLY - ECM)

(a) Disconnect the continuously variable valve lift controller assembly connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C116-4 (CAN+) - C77-31 (CAN+)

Always

Below 1 Ω

C116-2 (CAN-) - C77-32 (CAN-)

Always

Below 1 Ω

C116-3 (SDWN) - C77-136 (SDWN)

Always

Below 1 Ω

C116-4 (CAN+) or C77-31 (CAN+) - Body ground and other terminals

Always

10 kΩ or higher

C116-2 (CAN-) or C77-32 (CAN-) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

REPLACE CONTINUOUSLY VARIABLE VALVE LIFT CONTROLLER ASSEMBLY

(a) Replace the continuously variable valve lift controller assembly.

Click here 2020 MY Corolla [01/2019 - 03/2019]; 2ZR-FAE (ENGINE CONTROL): CONTINUOUSLY VARIABLE VALVE LIFT CONTROLLER: REMOVAL

HINT:

Perform "Inspection After Repair" after replacing the continuously variable valve lift controller assembly.

Click here 2020 - 2023 MY Corolla [01/2019 - 11/2022]; 2ZR-FAE (ENGINE CONTROL): SFI SYSTEM: INITIALIZATION

NEXT

4.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine and ECT > Clear DTCs

(e) Turn the ignition switch off and wait for at least 30 seconds.

NEXT

5.

PERFORM SIMULATION TEST

(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(b) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(c) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTC U011B is output

B

A

END

B

REPLACE ECM