Description

LF control unit power supply voltage low input

Detection condition

• Start stop unit power supply circuit voltage of 8.5 V or more or less than 16.5 V and LF control unit power supply circuit voltage of 5 V or more or less than 8.5 V are detected for 5 s or more.

Fail-safe function

• Inhibits the door lock/unlock control using the advanced keyless entry system.

Possible cause

• LF control unit connector or terminal malfunction

• Malfunction between battery positive terminal and LF control unit terminal A

• LF control unit malfunction

• Start stop unit malfunction

Step

Inspection

Action

1

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

• Disconnect the LF control unit connector.

• Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 4.

2

• Always reconnect all disconnected connectors.

• Reconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

• Measure the voltage at the LF control unit terminal A (wiring harness-side).

• Is the voltage 5 V or more or less than 8.5 V?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and LF control unit terminal A.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a malfunction.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Inspect the wiring harness between battery positive terminal and LF control unit terminal A (wiring harness-side).

• If there is any malfunction:

• Repair or replace the wiring harness.

• If there is no malfunction:

• Replace the LF control unit.

  (See LF CONTROL UNIT REMOVAL/INSTALLATION.)

Go to Step 4.

No

Go to the next step.

3

• Inspect the LF control unit.

  (See LF CONTROL UNIT INSPECTION.)

• Is the LF control unit normal?

Yes

Go to the next step.

No

Replace the LF control unit, then go to the next step.

(See LF CONTROL UNIT REMOVAL/INSTALLATION.)

4

• Always reconnect all disconnected connectors.

• Reconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

• Clear the DTC for the advanced keyless entry system using the M-MDS.

  (See CLEARING DTC [ADVANCED KEYLESS ENTRY SYSTEM].)

• Switch the ignition ON (engine off) and wait for 5 s or more.

• Retrieve the advanced keyless entry system DTCs using the M-MDS.

  (See DTC INSPECTION [ADVANCED KEYLESS ENTRY SYSTEM].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the start stop unit.

  (See START STOP UNIT REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

5

• Are any other DTCs displayed?

Yes

Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [ADVANCED KEYLESS ENTRY SYSTEM].)

No

DTC troubleshooting completed.