DTC A2-1x ("x" can be 0 thru 9 or A thru F): Faulty Power Supply (VB line)

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.

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 A2-1x 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.
Turn the ignition switch to LOCK (0).
Check the No. 22 (10 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?

YES -Go to step 6.

NO -Replace the fuse, then turn the ignition switch to ON (II). If the fuse blows again, check for a short to ground in the dashboard wire harness or in the under-dash fuse/relay box No. 22 (10A) fuse circuit; replace the dashboard wire harness. If the problem is still present, replace the under-dash fuse/relay box (see REMOVAL AND INSTALLATION ), then clear 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 ).
Reconnect the negative cable to the battery.
Turn the ignition switch to ON (II).
Measure the voltage between body ground and SRS unit connector A (39P) terminal No. 27.

Fig 1: Measuring Voltage Between Body Ground And SRS Unit Connector (39P) Terminal No. 27
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -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 (see SRS UNIT REPLACEMENT ).

NO -Open in the dashboard wire harness; replace the dashboard wire harness, then clear the DTC.