DTC U0028:88

DTC	System Malfunction Location
U0028:88	DSC HU/CM communication fault

DTC

System Malfunction Location

M-MDS display

U0028:88

DSC HU/CM communication fault

• Detection conditions are for understanding the DTC outline before performing an inspection. Performing an inspection with only detection conditions may cause injury due to an operating error, or damage the system. When performing an inspection, always follow the inspection procedure.

STEP	INSPECTION	ACTION
1	INSPECT DSC HU/CM CONNECTOR • Switch the ignition to off. • Disconnect the negative battery cable and wait for 1 min or more. • Disconnect the DSC HU/CM connector. • Inspect the DSC HU/CM connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 5.
No	Go to the next step.
2	INSPECT SAS CONTROL MODULE CONNECTOR • Disconnect the SAS control module connectors. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.) • Inspect the SAS control module connector terminal for poor connection (such as damaged/pulled-out pins, and corrosion). • Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 5.
No	Go to the next step.
3	INSPECT WIRING HARNESS BETWEEN DSC HU/CM AND SAS CONTROL MODULE • Inspect the wiring harness between SAS control module terminal 2K and DSC HU/CM terminal F, SAS control module terminal 2I and DSC HU/CM terminal G for the following: ― Short to body ground ― Open circuit ― Short circuit between terminals Note • Inspect for continuity while shaking the wiring harness between the DSC HU/CM and SAS control module. • Is the wiring harness normal?	Yes	Go to the next step.
No	Replace the wiring harness between the SAS control module and the DSC HU/CM.
4	INSPECT THE WIRING HARNESS BETWEEN THE SAS CONTROL MODULE AND DSC HU/CM FOR A SHORT CIRCUIT TO THE POWER SUPPLY • Connect the negative battery cable. • Switch the ignition to ON with SAS control module and DSC HU/CM connector disconnected. • Measure the voltage of SAS control module connector terminals 2K and 2I of SAS control module harness side connector. Note • Measure the voltage while shaking the wiring harness between the SAS control module and DSC HU/CM. • Is the voltage measured?	Yes	Repair or replace the wiring harness for a possible short to power supply, then go to the next step.
No	Replace the DSC HU/CM, then go to the next step. (See DSC HU/CM REMOVAL/INSTALLATION.)
5	VERIFY TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the SAS control module memory using the M-MDS. • Switch the ignition to off then switch the ignition to ON. • Is the same DTC present?	Yes	Replace the SAS control module. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.)
No	DTC troubleshooting completed.

STEP

INSPECTION

ACTION

INSPECT DSC HU/CM CONNECTOR

• Switch the ignition to off.

• Disconnect the negative battery cable and wait for 1 min or more.

• Disconnect the DSC HU/CM connector.

• Inspect the DSC HU/CM connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

Go to the next step.

INSPECT SAS CONTROL MODULE CONNECTOR

• Disconnect the SAS control module connectors. (See SAS CONTROL MODULE REMOVAL/INSTALLATION.)

• Inspect the SAS control module connector terminal for poor connection (such as damaged/pulled-out pins, and corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 5.

Go to the next step.

INSPECT WIRING HARNESS BETWEEN DSC HU/CM AND SAS CONTROL MODULE

• Inspect the wiring harness between SAS control module terminal 2K and DSC HU/CM terminal F, SAS control module terminal 2I and DSC HU/CM terminal G for the following:

― Short to body ground

― Open circuit

― Short circuit between terminals

Note

• Inspect for continuity while shaking the wiring harness between the DSC HU/CM and SAS control module.

• Is the wiring harness normal?

Yes

Go to the next step.

Replace the wiring harness between the SAS control module and the DSC HU/CM.

INSPECT THE WIRING HARNESS BETWEEN THE SAS CONTROL MODULE AND DSC HU/CM FOR A SHORT CIRCUIT TO THE POWER SUPPLY

• Connect the negative battery cable.

• Switch the ignition to ON with SAS control module and DSC HU/CM connector disconnected.

• Measure the voltage of SAS control module connector terminals 2K and 2I of SAS control module harness side connector.

Note

• Measure the voltage while shaking the wiring harness between the SAS control module and DSC HU/CM.

• Is the voltage measured?

Yes

Repair or replace the wiring harness for a possible short to power supply, then go to the next step.

Replace the DSC HU/CM, then go to the next step.

(See DSC HU/CM REMOVAL/INSTALLATION.)

VERIFY TROUBLESHOOTING COMPLETED

• Make sure to reconnect all disconnected connectors.

• Clear the DTC from the SAS control module memory using the M-MDS.

• Switch the ignition to off then switch the ignition to ON.

• Is the same DTC present?

Yes

Replace the SAS control module.

(See SAS CONTROL MODULE REMOVAL/INSTALLATION.)

DTC troubleshooting completed.