DTC Troubleshooting: U0155-00 (SRS Unit)

DTC Troubleshooting: U0155-00

DTC U0155-00: Lost Communication With the Gauge Control Module

NOTE:

	Before doing this troubleshooting procedure, find out if the vehicle was in a collision. If so, verify that all the required components were replaced with new components of the correct part number, and that they were properly installed.
	Before doing this troubleshooting procedure, review SRS Precautions and Procedures, General Troubleshooting Information, and 12 Volt Battery Terminal Disconnection and Reconnection.
	Before replacing the SRS unit, check the SRS unit software version with the HDS. If the software version is not the latest, update the SRS unit software, and retest.

DTC Description	DTC
U0155-00 Lost communication with the gauge control module

Body electrical system check:

Body electrical system check

?1.

Check for any F-CAN and B-CAN communication DTCs with the HDS.

DTC Description	DTC

Are there any communication DTCs?


	YES

Go to the appropriate DTC troubleshooting.?


	NO

Go to step 2.

Brake system indicator check:

Brake system indicator check

?1.	Release the parking brake, turn the vehicle to the OFF (LOCK) mode, and see if the brake system indicator comes on for 2 seconds and then goes off.

Does the brake system indicator come on and then go off after 2 second?


	YES

Go to step 3.


	NO

Do the gauge control module self-diagnostic function. If gauge control module has the problem, replace the gauge control module, then clear the DTC, and retest. If the DTC is still present, replace the SRS unit.?

DTC check:

DTC check

?1.	Clear the DTCs with the HDS.

?2.	Turn the vehicle to the ON mode, then wait for 10 seconds.

?3.

Check for DTCs with the HDS.

DTC Description	DTC
U0155-00 Lost communication with the gauge control module

Is DTC U0155-00 indicated?


	YES

Go to step 4.


	NO

Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures. If another DTC is indicated, troubleshoot the DTC.?

Open wire check (F-CAN_H, F-CAN_L lines):

Open wire check (F-CAN_H, F-CAN_L lines)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Disconnect the negative cable from the 12 volt battery, then wait at least 3 minutes.

?3.

Disconnect the following connectors.

SRS unit connector A (39P)

Gauge control module 32P connector

?4.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	SRS unit connector A (39P): disconnected
	Gauge control module 32P connector: disconnected
Test point 1	SRS unit connector A (39P) No. 20
Test point 2	Gauge control module 32P connector No. 21

Test point 1	SRS unit connector A (39P) No. 21
Test point 2	Gauge control module 32P connector No. 22

Is there continuity?


	YES

The F-CAN_H and F-CAN_L wires are OK. Faulty SRS unit or poor connection at SRS unit connector A (39P) and the SRS unit. Check the connection; if the connection is OK, replace the SRS unit. If the DTC does not clear, replace the dashboard wire harness.?


	NO

Open in the harness between SRS unit connector A (39P) terminal No. 20 and gauge control module 32P connector terminal No. 21, or between SRS unit connector A (39P) terminal No. 21 and gauge control module 32P connector terminal No. 22; replace the dashboard wire harness, then clear the DTC.?