DTC 45: Cal FL Brake Fluid Pressure Sensor Center Position Error

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.

Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Turn the ignition switch to ON (II), then wait for 10 seconds.
Watch the ACC indicator.
Does the ACC indicator (amber) go off?

YES -Go to step 4.

NO -Go to step 5.
Press the brake pedal, and watch the ACC indicator.
Does the ACC indicator (amber) go off?

YES -The system is OK at this time. Check for loose or poor connections.

NO -Go to step 5.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 45 indicated?

YES -Go to step 6.

NO -Troubleshoot the indicated DTCs. If there are no DTCs, the system is OK at this time.
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 9.

NO -Repair a short to ground in the wire between the ACC unit and the left front brake fluid pressure sensor.
Disconnect the left front brake fluid pressure sensor 3P connector (see step 2 under Brake Fluid Pressure Sensor Removal/Installation ).
Connect left front brake fluid pressure sensor 3P connector terminal No. 2 to body ground with a jumper wire.

Fig 2: Connecting Left 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 12.

NO -Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
Remove the jumper wire from the left 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 16.

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. 14 and body ground. There should be an open circuit or at least 1 MΩ.

Fig 5: Measuring Resistance Between ACC Unit 20P Connector And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 19.

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

Fig 6: Connecting Left 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. 14 and body ground. There should be less than 1.0 Ω.

Fig 7: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 14 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 22.

NO -Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
Measure the resistance between ACC unit 20P connector terminal No. 5 and No. 14. There should be an open circuit or at least 1 MΩ.

Fig 8: Measuring Resistance Between ACC Unit 20P Connector Terminal No. 5 And No. 14
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance as specified?

YES -Go to step 23.

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

Fig 9: Connecting Left 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 25.

NO -Repair an open in the wire between the ACC unit and the left front brake fluid pressure sensor.
Remove the jumper wire from the left front brake fluid pressure sensor.
Reconnect all connectors.
Turn the ignition switch to ON (II), then wait for 10 seconds.
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 30.

NO -Go to step 29.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 45 indicated?

YES -Go to step 31.

NO -Go to step 30.
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 ).
Measure the voltage between ACC unit 20P connector terminals No. 3 and No. 14. With the brake pedal released, there should be voltage between 0.4 - 0.6 V.

Fig 11: Measuring Voltage Between ACC Unit 20P Connector Terminals No. 3 And No. 14
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the voltage as specified?

YES -Go to step 32.

NO -Faulty left front brake fluid pressure sensor; replace the left front brake fluid pressure sensor (see BRAKE FLUID PRESSURE SENSOR REMOVAL/INSTALLATION ).
Clear the DTCs with the HDS (see HOW TO CLEAR DTCS ).
Watch the ACC indicator.
Does the ACC indicator (amber) go off?

YES -The system is OK at this time. Check for loose or poor connections.

NO -Go to step 34.
Check for DTCs with the HDS (see HOW TO CLEAR DTCS ).
Is DTC 45 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.