DTC 50: Cal FR Brake Fluid Pressure Sensor 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.

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 9.

NO -Go to step 6.
Activate BRAKE ACTUATOR 3 again.
While the brake actuator is operating, press the brake pedal.
Watch the ACC indicator.
Does the ACC indicator stay come on?

YES -Go to step 9.

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 50 indicated?

YES -Go to step 10.

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

YES -Go to step 11.

NO -Go to step 14.
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 right front brake fluid pressure voltage (RF BRAKE P) with the HDS.
Is there about 2.5 V?

YES -The right 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 14.
Turn the ignition switch to LOCK (0).
Disconnect the ACC unit 20P connector.
Measure the resistance between ACC unit 20P connector terminal No. 5 and body ground. There should be an open circuit or at least 1 MΩ.

Fig 1: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 5 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 17.

NO -Repair a short to ground in the wire between the ACC unit and the right front brake fluid pressure sensor.
Disconnect the right front brake fluid pressure sensor 3P connector.
Connect right front brake fluid pressure sensor 3P connector terminal No. 2 to body ground with a jumper wire.

Fig 2: Connecting Right Front Brake Fluid Pressure Sensor 3P Connector To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure the resistance between ACC unit 20P connector terminal No. 5 and body ground. There should be less than 1.0 Ω.

Fig 3: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 5 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 20.

NO -Repair an open in the wire between the ACC unit and the right front brake fluid pressure sensor.
Remove the jumper wire from the right front brake fluid pressure sensor.
Reconnect all connectors.
Turn the ignition switch to ON (II).
Measure the voltage between ACC unit 20P connector terminals No. 3 and No. 5. There should be about 5 V.

Fig 4: Measuring Voltage Between ACC Unit 20P Connector Terminals No. 3 And No. 5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the voltage as specified?

YES -Go to step 24.

NO -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 ).
Turn the ignition switch to LOCK (0).
Disconnect the ACC unit 20P connector.
Measure the resistance between ACC unit 20P connector terminal No. 6 and body ground. There should be an open circuit or at least 1 MΩ.

Fig 5: Measuring Resistance Between Acc Unit 20P Connector Terminal No. 6 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 27.

NO -Repair a short to ground in the wire between the ACC unit and the right front brake fluid pressure sensor.
Disconnect the right front brake fluid pressure sensor 3P connector.
Connect right front brake fluid pressure sensor 3P connector terminal No. 3 to body ground with a jumper wire.

Fig 6: Connecting Right Front Brake Fluid Pressure Sensor 3P Connector To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure the resistance between ACC unit 20P connector terminal No. 6 and body ground. There should be less than 1.0 Ω.

Fig 7: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 6 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 30.

NO -Repair an open in the wire between the ACC unit and the right front brake fluid pressure sensor.
Measure the resistance between ACC unit 20P connector terminals No. 5 and No. 6. There should be an open circuit or at least 1 MΩ.

Fig 8: Measuring Resistance Between ACC Unit 20P Connector Terminals No. 5 And No. 6
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 31.

NO -Repair a short in the wire between the PRESS FR line and the VCC line.
Connect right front brake fluid pressure sensor 3P connector terminal No. 1 to body ground with a jumper wire.

Fig 9: Connecting Right Front Brake Fluid Pressure Sensor 3P Connector To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure the resistance between ACC unit 20P connector terminal No. 3 and body ground. There should be less than 1.0 Ω.

Fig 10: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 33.

NO -Repair an open in the wire between the ACC unit and the right front brake fluid pressure sensor.
Remove the jumper wire from the right front brake fluid pressure sensor.
Reconnect all connectors.
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 38.

NO -Go to step 37.
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 BRAKE ACTUATOR 3 from the FUNCTION TEST menu.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 50 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 -Go to the VSA system troubleshooting (see GENERAL TROUBLESHOOTING INFORMATION ).