DTC 43: Cal FL Brake System Malfunction

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: In this troubleshooting, you will operate the ADAPTIVE CRUISE CONTROL (ACC) BRAKE (brake actuator 3) continuously four or five times using the FUNCTION TEST with the HDS. During this operation, the VSA modulator-control unit may stop working. This means the VSA modulator-control unit has shut down to protect the system from overheating during continuous operation.

If the VSA modulator-control unit stops working, wait for a few minutes until the VSA modulator-control unit cools down, then restart the troubleshooting.

Check for VSA system DTCs with the HDS (see PUMP MOTOR ).
Are any DTCs indicated?

YES -Troubleshoot the indicated VSA system DTC(s).

NO -Go to step 2.
Start the engine, and press the MAIN switch ON.
Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Select ADAPTIVE CRUISE CONTROL (ACC) from the DRIVING SUPPORT menu, then enter the FUNCTION TEST.
Activate BRAKE ACTUATOR 3 from the FUNCTION TEST menu.
Watch the ACC indicator.
Does the ACC indicator come on?

YES -Go to step 10.

NO -Go to step 7.
Activate BRAKE ACTUATOR 3 again.
While the brake actuator is operating, press the brake pedal.
Watch the ACC indicator.
Does the ACC indicator come on?

YES -Go to step 10.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 43 indicated?

YES -Go to step ii.

NO -Troubleshoot the indicated DTC(s). If there are no DTCs, the system is OK at this time.
Turn the ignition switch to LOCK (0).
Press the brake pedal several times, and check the brake pedal travel.
Does the brake pedal sink?

YES -Inspect the master cylinder (see MASTER CYLINDER INSPECTION ).

NO -Go to step 13.
Check for brake fluid leaks (see BRAKE HOSE AND LINE INSPECTION ).
Are there any leaks?

YES -Repair the brake fluid leak.

NO -Go to step 14.
Start the engine.
Check the brake switch signal (BRAKE SW (N.O.)) with the HDS.
Does the indication show ON when the brake pedal is pressed, and show OFF when the brake pedal is released?

YES -Go to step 17.

NO -Go to step 16.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 60, 110, or 111 indicated?

YES -Troubleshoot the indicated DTC(s).

NO -Troubleshoot the brake pedal position switch signal circuit (see BRAKE PEDAL POSITION SWITCH SIGNAL CIRCUIT TROUBLESHOOTING ).
Press the MAIN switch ON.
Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Select ADAPTIVE CRUISE CONTROL (ACC) from the DRIVING SUPPORT menu, then enter the FUNCTION TEST.
Activate the BRAKE ACTUATOR 3 from the FUNCTION TEST.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 43 indicated?

YES -Check the brake fluid pressure sensor for proper installation or leaks (see BRAKE FLUID PRESSURE SENSOR REMOVAL/INSTALLATION ). If OK, go to step 22.

NO -Troubleshoot the indicated DTC(s). If there is no DTCs, the system is OK at this time.
Without the brake pedal pressed, check the left front brake fluid pressure voltage (LF BRAKE P) with the HDS.
Is there about 0.5 V?

YES -Go to step 23.

NO -Go to step 26.
Test the brake booster (see MASTER CYLINDER INSPECTION ).
Start the engine, then press the brake pedal with about 314 N (32 kgf, 70.6 lbf) pressure.
Check the left front brake fluid pressure voltage (LF BRAKE P) with the HDS.
Is there about 2.5 V?

YES -The left front brake fluid pressure signal is OK, check for loose or poor connections. If OK, update the ACC unit (see ACC UNIT UPDATE ), then recheck. If the ACC unit was already updated, replace the ACC unit (see ADAPTIVE CRUISE CONTROL (ACC) UNIT REMOVAL/INSTALLATION ).

NO -Go to step 26.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 43 indicated?

YES -Check for loose or poor connections. If OK, update the ACC unit (see ACC UNIT UPDATE ), then recheck. If the ACC unit was already updated, replace the ACC unit (see ADAPTIVE CRUISE CONTROL (ACC) UNIT REMOVAL/INSTALLATION ).

NO -Troubleshoot the indicated DTC(s). If there are no DTCs, the system is OK at this time.