Description

Start stop unit power supply voltage (terminal 1A) low input

Detection condition

• Start stop unit power supply circuit voltage (terminal 1A) of 5V or more, less than 8.5 V is detected for 5 s or more.

Fail-safe

• The door lock and unlock may not operate using the advanced keyless entry system. (With advanced keyless entry system)

• The door lock and unlock may not operate using the keyless entry system. (With keyless entry system)

• When starting the engine, it may be necessary to use the method for starting the engine when the transmitter battery is dead.

Possible cause

• DTCs are stored in the PCM.

• Battery malfunction

• Generator malfunction

• Start stop unit connector or terminal malfunction

• Malfunction between battery positive terminal and start stop unit terminal 1A

• Start stop unit malfunction

Step

Inspection

Action

1

• Retrieve the PCM DTCs using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0)].)

• Are any DTCs displayed?

Yes

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

(See DTC TABLE [PCM (SKYACTIV-G 2.0)].)

No

Go to the next step.

2

• Inspect the battery.

  (See BATTERY INSPECTION.)

• Is the battery normal?

Yes

Go to the next step.

No

Recharge or replace the battery, then go to Step 6.

(See BATTERY RECHARGING.)

(See BATTERY REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

3

• Inspect the generator.

  (See GENERATOR INSPECTION [SKYACTIV-G 2.0].)

• Is the generator normal?

Yes

Go to the next step.

No

Replace the generator, then go to Step 6.

(See GENERATOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)

4

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Disconnect the start stop 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 6.

5

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Display PID VPWR_B1 using the M-MDS.

  (See PID/DATA MONITOR INSPECTION [START STOP UNIT].)

• Is the voltage B+?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and start stop unit terminal 1A.

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 battery positive terminal and start stop unit terminal 1A.

• If there is any malfunction:

• Repair or replace the wiring harness.

• If there is no malfunction:

• Replace the start stop unit.

  (See START STOP UNIT REMOVAL/INSTALLATION.)

Go to the next step.

6

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the start stop unit using the M-MDS.

  (See CLEARING DTC [START STOP UNIT].)

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

• Retrieve the start stop unit DTCs using the M-MDS.

  (See DTC INSPECTION [START STOP UNIT].)

• 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.

7

• Are any other DTCs displayed?

Yes

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

(See DTC TABLE [START STOP UNIT].)

No

DTC troubleshooting completed.