Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM100000001GHAN
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 03/2019]
Title: 2ZR-FAE (ENGINE CONTROL): SFI SYSTEM: P104A; VALVEMATIC SDOWN Circuit; 2020 MY Corolla [01/2019 - 03/2019]

DTC

P104A

VALVEMATIC SDOWN Circuit

DESCRIPTION

The ECM turns the power supply to the continuously variable valve lift controller assembly on/off. Normally, when the ignition switch is ON, +B voltage is constantly supplied to the continuously variable valve lift controller assembly. However, when a malfunction is detected in the VALVEMATIC system, the ECM turns the power supply to the continuously variable valve lift controller assembly off. The power supply is turned on/off through the shutdown (SDWN) signal line between the ECM and continuously variable valve lift controller assembly.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P104A

VALVEMATIC SDOWN Circuit

Shutdown (SDWN) signal line has a short circuit to +B or ground (1 trip detection logic):

  • Shutdown (SDWN) signal line short circuit to +B: While the ignition switch is off, even though the CPU in the ECM requests shutdown (SDWN) signal Low, the monitor detects High
  • Short circuit (Short circuit to ground): While the ignition switch is ON, even though the CPU in the ECM requests shutdown (SDWN) signal High, the monitor detects Low
  • Short in continuously variable valve lift controller assembly circuit
  • ECM

Comes on

DTC stored

MONITOR DESCRIPTION

When the ignition switch is turned to ON, the ECM turns the shutdown (SDWN) signal on (High) which turns the continuously variable valve lift controller assembly power on. Also, when the ignition switch is off or during fail-safe mode, the shutdown (SDWN) signal is turned off (Low) which turns the continuously variable valve lift controller assembly power off.

The ECM electrically monitors if the shutdown (SDWN) signal is actually turned on/off by the output circuit of the CPU. If the power supply to the continuously variable valve lift controller assembly is not turned on/off according to the shutdown (SDWN) signal, the ECM will illuminate the MIL and store this DTC.

MONITOR STRATEGY

Related DTCs

P104A: Rocker arm control module power supply line range check (low voltage)

P104A: Rocker arm control module power supply line range check (high voltage)

Required Sensors/Components (Main)

Continuously variable valve lift controller assembly

ECM

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.15 seconds

MIL Operation

Immediate

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

Both of the following conditions is met

-

Battery voltage

8 V or higher

Starter

Off

TYPICAL MALFUNCTION THRESHOLDS

Low Voltage

Rocker arm control module power supply line output terminal voltage level

Low

High Voltage

Rocker arm control module power supply line output terminal voltage level

High

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.
  5. Turn the ignition switch off and wait for at least 30 seconds.
  6. Turn the ignition switch to ON and wait 5 seconds.
  7. Turn the ignition switch off and wait for at least 30 seconds.
  8. Turn the ignition switch to ON.
  9. Turn the Techstream on.
  10. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
  11. 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.
  12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  13. Input the DTC: P104A.
  14. 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.
  15. 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

HINT:

  • After performing repairs, perform the following procedures 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 ANY OTHER DTCS OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

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

(e) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result

Proceed to

DTC P104A is output

A

DTC P1049 is output at same time as DTC P104A

B
B

GO TO DTC CHART

A

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

C116-3 (SDWN) or C77-136 (SDWN) - Body ground and other terminals

Always

10 kΩ or higher
OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR