DTC 112: Lost Communication with the VSA Modulator-Control Unit

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.

Check the VSA indicator on the gauge control module (see GENERAL TROUBLESHOOTING INFORMATION ).
Does the VSA indicator (amber) stay on?

YES -Go to step 2.

NO -Go to step 3.
Check for VSA system DTCs with the HDS (see PUMP MOTOR ).
Are there any VSA system DTCs?

YES -Go to step 3.

NO -Troubleshoot the VSA system.
Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Turn the ignition switch to ON (II), then wait for 10 seconds.
Press the MAIN switch ON.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 112 indicated?

YES -Go to step 7.

NO -Intermittent failure, the system is OK at this time.
Test-drive the vehicle in a straight line, and check all four wheel speed signals (LF WHEEL SPEED, RF WHEEL SPEED, LR WHEEL SPEED, RR WHEEL SPEED) with the HDS. (ACC system)
Does HDS correspond to the vehicle speed indicated in the meter?

YES -Go to step 13.

NO -Go to step 8.
Turn the ignition switch to LOCK (0).
Disconnect the ACC unit 20P connector.
Disconnect the VSA modulator-control unit 46P connector.
Check for continuity between ACC unit 20P connector terminal No. 7 and VSA modulator-control unit 46P connector terminal No. 22.

Fig 1: Checking Continuity Between ACC Unit 20P Connector And VSA Modulator-Control Unit 46P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 12.

NO -Repair an open in the wire between the ACC unit and the branch of the F-CAN B line (F-CAN B H).
Check for continuity between ACC unit 20P connector terminal No. 18 and VSA modulator-control unit 46P connector terminal No. 1.

Fig 2: Checking Continuity Between ACC Unit 20P Connector Terminal No. 18 And VSA Modulator-Control Unit 46P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty VSA modulator-control unit; replace the VSA modulator-control unit.

NO -Repair an open in the wire between the ACC unit and the branch of the F-CAN B line (F-CAN B L).
Turn the ignition switch to LOCK (0).
Disconnect the ACC unit 20P connector.
Disconnect the VSA modulator-control unit 46P connector.
Check for continuity between ACC unit 20P connector terminal No. 10 and VSA modulator-control unit 46P connector terminal No. 39.

Fig 3: Checking Continuity Between ACC Unit 20P Connector Terminal No. 10 And VSA Modulator-Control Unit 46P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 17.

NO -Repair an open in the wire between the ACC unit and the branch of the F-CAN A line (F-CAN A H).
Check for continuity between ACC unit 20P connector terminal No. 20 and VSA modulator-control unit 46P connector terminal No. 38.

Fig 4: Checking Continuity Between ACC Unit 20P Connector Terminal No. 20 And VSA Modulator-Control Unit 46P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty VSA modulator-control unit; replace the VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).

NO -Repair an open in the wire between the ACC unit and the branch of the F-CAN A line (F-CAN A L).