DTC U3003:16

DC-DC converter system: power supply voltage low input

DETECTION CONDITION

• The following condition is met for a continuous 5 s period:

• DC-DC converter terminal 4A voltage: 8 V or less

FAIL-SAFE FUNCTION

• Not applicable

POSSIBLE CAUSE

• PCM DTC or pending code is stored.

• Battery malfunction

• DC-DC converter connector or terminals malfunction

• Malfunction in the following fuses:

• STARTER 250 A fuse

• MAIN 200 A fuse

• Short to ground in wiring harness between battery positive terminal and DC-DC converter terminal 4A

• Open circuit in wiring harness between battery positive terminal and DC-DC converter terminal 4A

• Generator malfunction

• DC-DC converter malfunction

STEP

INSPECTION

ACTION

1

• Verify related Service Bulletins and/or on-line repair information availability.

• Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

• If the vehicle is not repaired, go to the next step.

No

Go to the next step.

2

• Switch the ignition off, then ON (engine off).

• Retrieve the PCM DTCs using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].)

• Are any DTCs present?

Yes

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

(See DTC TABLE [SKYACTIV-G 2.5].)

No

Go to the next step.

3

• Inspect the battery.

  (See BATTERY INSPECTION [SKYACTIV-G 2.5].)

• Is there any malfunction?

Yes

Recharge or replace the battery, then go to Step 9.

(See BATTERY RECHARGING [SKYACTIV-G 2.5].)

(See BATTERY REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Go to the next step.

4

• Switch the ignition off.

• Disconnect the negative battery cable.

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

• Disconnect the service plug.

  (See SERVICE PLUG DISCONNECTION/CONNECTION [i-ELOOP].)

• Disconnect the DC-DC converter connector.

• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the connector and/or terminals, then go to Step 9.

No

Go to the next step.

5

• Remove the following fuses:

• STARTER 250 A fuse

• MAIN 200 A fuse

• Inspect the following fuses:

• STARTER 250 A fuse

• MAIN 200 A fuse

• Are all the fuses normal?

Yes

Install all the removed fuses, then go to the next step.

No

If the fuse is blown out:

• Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and DC-DC converter terminal 4A.

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 short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

• Replace the malfunctioning fuse.

If the fuse is damaged:

• Replace the malfunctioning fuse.

Go to Step 9.

6

• Verify that the DC-DC converter connector is disconnected.

• Inspect for continuity between DC-DC converter terminal 4A (wiring harness-side) and body ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and DC-DC converter terminal 4A.

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 short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

Go to Step 9.

No

Go to the next step.

7

• Verify that the DC-DC converter connector is disconnected.

• Inspect for continuity between battery positive terminal and DC-DC converter terminal 4A (wiring harness-side).

• Is there continuity?

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 DC-DC converter terminal 4A.

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 an open circuit.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to Step 9.

8

• Inspect the generator.

  (See GENERATOR INSPECTION [i-ELOOP].)

• Is there any malfunction?

Yes

Replace the generator, then go to the next step.

(See GENERATOR REMOVAL/INSTALLATION [i-ELOOP].)

No

Go to the next step.

9

• Always reconnect all disconnected connectors.

• Reconnect the negative battery cable.

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

• Reconnect the service plug.

  (See SERVICE PLUG DISCONNECTION/CONNECTION [i-ELOOP].)

• Clear the DTC for the DC-DC converter using the M-MDS.

  (See CLEARING DTC [i-ELOOP].)

• Switch the ignition off.

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

• Retrieve the DC-DC converter DTCs using the M-MDS.

  (See DTC INSPECTION [i-ELOOP].)

• Is the same DTC present?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the DC-DC converter.

  (See DC-DC CONVERTER REMOVAL/INSTALLATION [i-ELOOP].)

Go to the next step.

No

Go to the next step.

10

• Are any other DTCs displayed?

Yes

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

(See DTC TABLE [i-ELOOP].)

No

DTC troubleshooting completed.