DTC 56-25: Lost Communication With the Gauge Control Module

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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 (see COMPONENT REPLACEMENT/INSPECTION AFTER DEPLOYMENT ).
Before doing this troubleshooting procedure, review SRS PRECAUTIONS AND PROCEDURES , GENERAL TROUBLESHOOTING INFORMATION , and Battery Terminal Disconnection and Reconnection (see USING THE GR8 BATTERY DIAGNOSTIC STATION ).
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 (see SRS UNIT UPDATE ), and retest.

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

YES -Go to the appropriate DTC TROUBLESHOOTING .

NO -Go to step 2.
Release the parking brake, turn the ignition switch to ON (II), and see if the brake system light comes on for 2 seconds and then goes off.
Does the brake system light come on?

YES -Go to step 3.

NO -Faulty gauge control module. Do the gauge control module self-diagnostic function (see SELF-DIAGNOSTIC FUNCTION ).
Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Turn the ignition switch to ON (II), then wait for 10 seconds.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 56-25 indicated?

YES -Go to step 6.

NO -Intermittent failure, the system is OK at this time. Go to TROUBLESHOOTING INTERMITTENT FAILURES . If another DTC is indicated, troubleshoot the DTC.
Turn the ignition switch to LOCK (0).
Disconnect the negative cable from the battery, then wait at least 3 minutes.
Disconnect SRS unit connector A (39P) from the SRS unit (see DISCONNECTING SYSTEM CONNECTORS ).
Disconnect gauge control module connector A (12P) from the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).
Check for continuity between SRS unit connector A (39P) terminals No. 16 and No. 17 and gauge control module connector A (12P) terminals No. 6 and No. 12.

Fig 1: Checking Continuity Between SRS Unit Connector (39P) Terminals No. 16 And No. 17 And Gauge Control Module Connector (12P) Terminals No. 6 And No. 12
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty SRS unit or poor connection at SRS unit connector A (39P) and the SRS unit. Check the connection between the connector and the SRS unit. If the connection is OK, replace the SRS unit (see SRS UNIT REPLACEMENT ).

NO -Open between SRS unit connector A (39P) terminal No. 16 and gauge control module connector A (12P) terminal No. 6, and between SRS unit connector A (39P) terminal No. 17 and gauge control module connector A (12P) terminal No. 12; replace the faulty harness, then clear the DTC.