DTC U0155-00: Lost Communication With the Gauge Control Module (SRS Unit, Without CAN gateway)

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 - Refer to: SRS Component Replacement/Inspection After Deployment (2015-17) or SRS Component Replacement/Inspection After Deployment (2018-19) .
Before doing this troubleshooting procedure, review SRS Precautions and Procedures , General Troubleshooting Information - Refer to: How to Troubleshoot the SRS (2015-17) or How to Troubleshoot the SRS (2018-19) , 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

DTC (SRS)

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.

Go to step 2.

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 - Refer to: Gauges Self-Diagnostic Function (Without SH-AWD) or Gauges Self-Diagnostic Function (With SH-AWD) . 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 - Refer to: SRS Unit Removal and Installation (2015-17) or SRS Unit Removal and Installation (2018-19) .

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 (L4 engine)

Go to step 4.

YES (V6 engine)

Go to step 5.

Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures - Refer to: How to Troubleshoot the SRS (2015-17) or How to Troubleshoot the SRS (2018-19) . If another DTC is indicated, troubleshoot the DTC.

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 - Refer to: SRS Unit Connector for Inputs and Outputs (2015-17) or SRS Unit Connector for Inputs and Outputs (2018-19)
Test point 2	Gauge control module 32P connector No. 27 - Refer to: Gauge Control Module Input Test (2015-17) or Gauge Control Module Input Test (2018-19)

Test point 1

SRS unit connector A (39P) No. 21 - Refer to: SRS Unit Connector for Inputs and Outputs (2015-17) or SRS Unit Connector for Inputs and Outputs (2018-19)

Test point 2

Gauge control module 32P connector No. 28 - Refer to: Gauge Control Module Input Test (2015-17) or Gauge Control Module Input Test (2018-19)

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 - Refer to: SRS Unit Removal and Installation (2015-17) or SRS Unit Removal and Installation (2018-19) . If the DTC does not clear, replace the dashboard wire harness.

Open in the harness between SRS unit connector A (39P) terminal No. 20 and gauge control module 32P connector terminal No. 27, or between SRS unit connector A (39P) terminal No. 21 and gauge control module 32P connector terminal No. 28; replace the dashboard wire harness, then clear the DTC.

Open wire check (F-CAN A_H, F-CAN A_L lines)