Vsa System Components: Other Acura RDX I facelift

System Indicator ('10-11 Models)

This system has four indicators

Scheme 35

1. ABS indicator (A)
2. Brake system indicator (B)
3. VSA indicator (C)
4. VSA activation indicator (D)

When the system detects a problem, it will turn the appropriate indicators on. Depending on the failure, the VSA modulator-control unit determines which indicators are turned on.

When the system is OK, each indicator comes on for about 2 seconds after turning the ignition switch to ON (II), then goes off.

ABS indicator

The ABS indicator comes on when the ABS function is lost. The brakes still work like a conventional system.

Brake system indicator

The brake system indicator comes on when the EBD function is lost, the parking brake is applied, and/or the brake fluid level is low.

Note. If two or more wheel speed sensors fail, the brake system indicator comes on.

VSA indicator

The VSA indicator comes on when the VSA function is lost.

VSA activation indicator

The VSA activation indicator blinks when the VSA function is activating. The VSA activation indicator comes on and stays on when the VSA is turned OFF by pressing the VSA OFF button or when VSA function is lost.

ABS and VSA indicators go off

Each indicator will go off after a problem goes away, but the timing which the VSA modulator-control unit turns off the indicators varies between DTCs.

1. DTC 61 or 62: The indicators go off automatically when the system returns to normal.
2. DTC 11, 13, 15, 17, 25, 26, 27*, 31, 32, 33, 34, 35, 36, 37, 38, 54, 66, 68, 81, 83, 84, 86, 87, 88, 91**, 113, 114 121, 122, 123, 124, 131*, 132, 133, 134, 137, or 138 The indicators stay on until the ignition switch is turned to LOCK (0), whether or not the system returns to normal. *: There are some cases that the indicators stay on until the vehicle is driven after the system returns to normal. **: There are some case that the indicators go off automatically when the system returns to normal.
3. DTC 12, 14, 16, 18, 21, 22, 23, 24, 51, 52, or 53: The indicators stay on until the vehicle is driven after the system returns to normal.

System Indicator ('12 Model)

This system has four indicators and one warning

Scheme 36

1. ABS indicator (A)
2. Brake system indicator (B)
3. VSA indicator (C)
4. VSA OFF indicator (D)

When the system detects a problem, it will turn the appropriate indicator on. Depending on the failure, the VSA modulator-control unit determines which indicators are turned on.

When the system is OK, each indicator comes on for about 2 seconds after turning the ignition switch to ON (II), then goes off.

The ABS indicator comes on when the ABS function is lost. The brakes still work like a conventional system.

The brake system indicator comes on when the EBD function is lost, the parking brake is applied, and/or the brake fluid level is low.

The VSA indicator comes on, when VSA function is lost. The VSA indicator blinks, when the VSA function is activating.

VSA OFF Indicator

The VSA OFF indicator comes on, when the VSA is turned OFF by using the VSA OFF switch.

Each indicator or warning will go off after a problem goes away, but the timing which the VSA modulator-control unit turns off the indicators or warning varies between DTCs.

1. DTC 61, 62: The indicators go off automatically when the system returns to normal.
2. DTC 11, 13, 15, 17, 25, 65, 81, 84, 86, 113, or 158: The indicators stay on until the ignition switch is turned to LOCK (0) whether or not the system returns to normal.
3. DTC 12, 14, 16, 18, 21, 22, 23, 24, 26, 27, 31, 32, 33, 34, 35, 36, 37, 38, 51, 52, 53, 54, 66, 68, 83, 88, 91, 121, 122, 123, 124, 131, 132, 133, 134, 137, or 138

The indicators stay on until the vehicle is driven after the system returns to normal.

Kickback

The pump motor operates when the VSA modulator-control unit is functioning, and the fluid in the reservoir is forced out to the master cylinder, causing kickback at the brake pedal.

Pump Motor

1. The pump motor operates when the VSA modulator-control unit is functioning.
2. The VSA modulator-control unit checks the pump motor operation one time after completing initial diagnosis during regular diagnosis when the vehicle is driven over 10 mph (15 km/h). You may hear the motor operate at this time, but it is normal.

Intermittent Failures

The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the indicator(s) of the system does not come on, check for loose connectors or terminals, pins related to the circuit that you are troubleshooting. If the indicators were on but then went out, the original problem may have been intermittent.

How to Retrieve DTCs

1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, troubleshoot the DLC circuit (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513833-S41457160082012111600000) ).
4. Follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC, refer to the «DTC TROUBLESHOOTING»(ref-513874-S31843025342012111600000) . Do the all systems DTC check, and troubleshoot any powertrain DTCs first.
5. Turn the ignition switch to LOCK (0).

How to Clear DTCs

1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, troubleshoot the DLC circuit (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513833-S41457160082012111600000) ).
4. Clear the DTC(s) by following the screen prompts on the HDS.
5. Turn the ignition switch to LOCK (0).

System Outline

This system is composed of the VSA modulator-control unit, the wheel speed sensors, the steering angle sensor, the yaw rate-lateral acceleration sensor, and the system indicators in the gauge control module. The VSA modulator-control unit controls the ABS, EBD, TCS, VSA, and brake assist with the brake pressure of each wheel and reduces engine torque.

Scheme 37

Anti-Lock Control

Without ABS, when the brake pedal is pressed while driving, the wheels sometimes lock before the vehicle comes to a stop. In such an event, the maneuverability of the vehicle is reduced if the front wheels are locked, and the stability of the vehicle is reduced if the rear wheels are locked, creating an extremely unstable condition. With ABS, the system precisely controls the slip rate of the wheels to ensure maximum grip force from the tires, and it thereby ensures maneuverability and stability of the vehicle. The ABS calculates the slip rate of the wheels based on the four wheel speeds, and then it controls the brake fluid pressure to reach the target slip rate.

Scheme 38

Main Control

The control unit detects the wheel speed based on the wheel speed sensor signals it received, then it calculates the vehicle speed based on the detected wheel speed. The control unit detects the vehicle speed during deceleration based on the wheel speeds.

The control unit calculates the slip rate of each wheel, and transmits the control signal to the modulator unit solenoid valve when the slip rate is high.

The hydraulic control has three modes: Pressure intensifying, pressure reducing, and pressure retaining.

Scheme 39

EBD (Electronic Brake Distribution) Features

The EBD feature helps control vehicle braking by adjusting the rear brake force in accordance with the rear wheel load before the ABS operates. Based on the wheel speed sensor signals, the control unit uses the modulator to control the rear brakes individually. When the rear wheel speed is less than the front wheel speed, the VSA modulator-control unit retains the current rear brake fluid pressure by closing the inlet valve in the modulator. As the rear wheel speed increases and approaches the front wheel speed, the VSA modulator-control unit increases the rear brake fluid pressure by momentarily opening the inlet valve. This whole process is repeated very rapidly. While this is happening, kickback may be felt at the brake pedal, you may also hear a muted buzzing sound from the VSA modulator-control unit. This is normal.

Scheme 40

TCS (Traction Control System) Features

When a drive wheel loses traction on a slippery road surface and starts to spin, the VSA modulator-control unit applies brake pressure to the spinning wheel and sends an engine torque control request to the PCM to slow the spinning wheel and keep traction.

Scheme 41

Oversteer Control

Applies braking to the front and rear outside wheels

Scheme 42

Scheme 43

1. Applies braking to the front and rear inside wheels
2. Controls the engine torque when accelerating

Brake Assist Features

Brake assist helps ensure that any driver can achieve the full braking potential of the vehicle by increasing brake system pressure in a panic situation, bringing the vehicle into a full ABS stop.

Each time the ignition switch is turned to ON (II), the VSA modulator-control unit learns the current driver's normal braking characteristics by monitoring the brake pressure sensor and the brake pedal position switch at each stop. Using these inputs and their values, the VSA modulator-control unit is able to learn the driver's normal braking habits, and then determine the difference between a normal stop and a panic stop for the individual driver of the vehicle. If during a panic stop the VSA modulator-control unit determines that the brake system pressure increases above a learned threshold in less than a learned amount of time, the VSA modulator-control unit engages brake assist.

Because the brake system pressure crossed the threshold before the time threshold had expired, the VSA modulator-control unit goes into brake assist mode.

Scheme 44

Modulator Unit

The modulator unit consists of the inlet solenoid valve, the outlet solenoid valve, the VSA NO (normally open) solenoid valve, the VSA NC (normally closed) solenoid valve, the reservoir, the pump, the pump motor, and the damping chamber.

The hydraulic control has three modes at ABS action; pressure intensifying, pressure retaining, and pressure reducing. And pressure adding mode is combined at TCS, VSA, and brake assist action.

The hydraulic circuit is an independent four channel type; one channel for each wheel.

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

1. Turn the ignition switch to ON (II).
2. Check for DTCs with the HDS. Is DTC 87 indicated with DTC 11, 13, 15, or 17 at the same time? YES -Go to step 9 . NO -Go to step 3.
3. Clear the DTC with the HDS.
4. Turn the ignition switch to LOCK (0), then turn it to ON (II) again.
5. Check for DTCs with the HDS. Is DTC 11, 13, 15, or 17 indicated? YES -Go to step 6. NO -Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting (see «INTERMITTENT FAILURES»(ref-513874-S18858288932012111600000) ).
6. Turn the ignition switch to LOCK (0).
7. Check for loose terminals between the wheel speed sensor 2P connector and the VSA modulator-control unit 46P connector. Are the terminals OK? YES -Go to step 8. NO -Repair the connector or terminals if possible, or replace the harness, and recheck.
8. Check that the appropriate wheel speed sensor is properly mounted (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ). DTC Appropriate Wheel Speed Sensor 11 Right-Front 13 Left-Front 15 Right-Rear 17 Left-Rear Is the wheel speed sensor installation OK? YES -Go to step 10 . NO -Reinstall the wheel speed sensor, and check the mounting position (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).
9. Turn the ignition switch to LOCK (0).
10. Disconnect the VSA modulator-control unit 46P connector (see step 2 ).
11. Turn the ignition switch to ON (II).
12. Measure the voltage between body ground and the appropriate wheel speed sensor +B and GND terminals of the VSA modulator-control unit 46P connector individually (see table). DTC Appropriate Terminal +B GND 11 (Right-Front) FR +B: No. 29 FR-GND: No. 28 13 (Left-Front) FL +B: No. 12 FL-GND: No. 34 15 (Right-Rear) RR +B: No. 30 RR-GND: No. 8 17 (Left-Rear) RL +B: No. 11 RL-GND: No. 10 Is there 0.1 V or more? YES -Repair a short to power in the wire between the VSA modulator-control unit and the appropriate wheel speed sensor. NO -Go to step 13.
13. Turn the ignition switch to LOCK (0).
14. Check for continuity between body ground and the appropriate wheel speed sensor + B and GND terminals of the VSA modulator-control unit 46P connector individually (see table). DTC Appropriate Terminal +B GND 11 (Right-Front) FR +B: No. 29 FR-GND: No. 28 13 (Left-Front) FL +B: No. 12 FL-GND: No. 34 15 (Right-Rear) RR +B: No. 30 RR-GND: No. 8 17 (Left-Rear) RL +B: No. 11 RL-GND: No. 10 Is there continuity? YES -Go to step 15. NO -Go to step 17 .
15. Disconnect the appropriate wheel speed sensor 2P connector (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).
16. Check for continuity between body ground and the appropriate wheel speed sensor +B and GND terminals of the VSA modulator-control unit 46P connector individually (see table). DTC Appropriate Terminal +B GND 11 (Right-Front) FR +B: No. 29 FR-GND: No. 28 13 (Left-Front) FL +B: No. 12 FL-GND: No. 34 15 (Right-Rear) RR +B: No. 30 RR-GND: No. 8 17 (Left-Rear) RL +B: No. 11 RL-GND: No. 10 Is there continuity? YES -Repair a short to body ground in the wire between the VSA modulator-control unit and the wheel speed sensor. NO -Replace the appropriate wheel speed sensor (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).
17. Disconnect the appropriate wheel speed sensor 2P connector (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).
18. Check for continuity between the appropriate wheel speed sensor +B and GND terminals of the VSA modulator-control unit 46P connector (see table). DTC Appropriate Terminal +B GND 11 (Right-Front) FR +B: No. 29 FR-GND: No. 28 13 (Left-Front) FL +B: No. 12 FL-GND: No. 34 15 (Right-Rear) RR +B: No. 30 RR-GND: No. 8 17 (Left-Rear) RL +B: No. 11 RL-GND: No. 10 Is there continuity? YES -Repair a short in the wires between the VSA modulator-control unit and the appropriate wheel speed sensor. NO -Go to step 19.
19. Connect wheel speed sensor 2P connector terminals No. 1 and No. 2 to body ground with a jumper wire. DTC Appropriate Wheel Speed Sensor 11 Right-Front 13 Left-Front 15 Right-Rear 17 Left-Rear
20. Check for continuity between body ground and the appropriate wheel speed sensor +B and GND terminals of the VSA modulator-control unit 46P connector individually (see table). DTC Appropriate Terminal +B GND 11 (Right-Front) FR +B: No. 29 FR-GND: No. 28 13 (Left-Front) FL +B: No. 12 FL-GND: No. 34 15 (Right-Rear) RR +B: No. 30 RR-GND: No. 8 17 (Left-Rear) RL +B: No. 11 RL-GND: No. 10 Is there continuity? YES -Go to step 21. NO -Repair an open in the wire between the VSA modulator-control unit and the appropriate wheel speed sensor.
21. Substitute the appropriate wheel speed sensor with the opposite side wheel speed sensor, or with a known-good wheel speed sensor (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).
22. Reconnect all connectors.
23. Turn the ignition switch to ON (II).
24. Clear the DTC with the HDS.
25. Turn the ignition switch to LOCK (0), then turn it to ON (II) again.
26. Check for DTCs with the HDS. Is the same DTC indicated that is indicated in step 5 ? YES -Check for loose terminals in the VSA modulator-control unit 46P connector. If it is OK, replace the VSA modulator-control unit (see «VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION»(ref-513874-S31080365882012111600000) ). NO -Replace the original wheel speed sensor (see «WHEEL SPEED SENSOR REPLACEMENT»(ref-513874-S31124354042012111600000) ).

VSA cannot be turned OFF ('12 model)

Note. If the TPMS indicator turns ON, the VSA cannot be turned OFF. Troubleshoot TPMS first.

Scheme 57

Scheme 58

Scheme 59

1. Turn the ignition switch to LOCK (0).
2. Check the VSA OFF switch (see «VSA OFF SWITCH TEST/REPLACEMENT»(ref-513874-S33331847752012111600000) ). Is the VSA OFF switch OK? YES -Go to step 3. NO -Replace the VSA OFF switch (see «VSA OFF SWITCH TEST/REPLACEMENT»(ref-513874-S33331847752012111600000) ).
3. Disconnect the VSA OFF switch 5P connector.
4. Disconnect gauge control module 36P connector (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513857-S10657424772012111600000) ).
5. Check for continuity between gauge control module 36P connector terminals No. 13 and VSA OFF switch 5P connector terminal No. 2. Is there continuity? YES -Go to step 6. NO -Repair an open in the wire between the gauge control module and the VSA OFF switch.
6. Check for continuity between VSA OFF switch 5P connector terminal No. 2 and body ground. Is there continuity? YES -Repair a short to body ground in the wire between the gauge control module and the VSA OFF switch. NO -Go to step 7.
7. Check for continuity between VSA OFF switch 5P connector terminal No. 1 and body ground. Is there continuity? YES -Substitute a known-good gauge control module (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513857-S10657424772012111600000) ), than go to step 1 and recheck. If it is OK, replace the original gauge control module (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513857-S10657424772012111600000) ). NO -Repair an open in the wire between the VSA OFF switch and body ground (G501).

Scheme 60

Scheme 61

Scheme 62

Scheme 63

1. Turn the ignition switch to LOCK (0).
2. Check the No. 4 (7.5 A) fuse in the under-dash fuse/relay box. Is the fuse blown? YES -Go to step 3. NO -Reinstall the checked fuse, then go to step 7 .
3. Disconnect the VSA modulator-control unit 46P connector (see step 2 ).
4. Check for continuity between VSA modulator-control unit 46P connector terminal No. 40 and body ground. Is there continuity? YES -Repair a short to body ground in the wire between the No. 4 (7.5 A) fuse in the under-dash fuse/relay box and the VSA modulator-control unit, the yaw rate-lateral acceleration sensor, and the steering angle sensor. NO -Install a new No. 4 (7.5 A) fuse in the under-dash fuse/relay box, then go to step 5.
5. Reconnect all connectors.
6. Check the ABS indicator, the brake system indicator, and the VSA indicator for several seconds when the ignition switch is turned to ON (II). Do the indicators come on then go off? YES -Troubleshooting is complete. NO -Check for loose terminals in the VSA modulator-control unit 46P connector. If it is OK, replace the VSA modulator-control unit (see «VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION»(ref-513874-S31080365882012111600000) ).
7. Disconnect the VSA modulator-control unit 46P connector (see step 2 ).
8. Turn the ignition switch to ON (II).
9. Measure the voltage between VSA modulator-control unit 46P connector terminal No. 40 and body ground. Is there battery voltage? YES -Go to step 10. NO -Repair an open in the wire between the No. 4 (7.5 A) fuse in the under-dash fuse/relay box and the VSA modulator-control unit.
10. Turn the ignition switch to LOCK (0).
11. Check for continuity between VSA modulator-control unit 46P connector terminal No. 43 and body ground. Is there continuity? YES -Go to step 12. NO -Repair an open in the wire between the VSA modulator-control unit and body ground (G402).
12. Disconnect the gauge control module 36P connector (see «GAUGE CONTROL MODULE REPLACEMENT»(ref-513857-S10657424772012111600000) ).
13. Check for continuity between VSA modulator-control unit 46P connector terminal and gauge control module 36P connector terminal (see table). Sign VSA Modulator-control Unit 46P Connector Terminal Gauge Control Module 36P Connector Terminal F-CAN L No. 38 No. 29 F-CAN H No. 39 No. 28 Is there continuity? YES -Check for loose terminals in the VSA modulator-control unit 46P connector. If it is OK, replace the VSA modulator-control unit (see «VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION»(ref-513874-S31080365882012111600000) ). NO -Repair an open in the wire between the gauge control module and the VSA modulator-control unit.

Steering Angle Sensor Center Point Writing

Note. Before doing the steering angle sensor center point writing, put the vehicle on a flat level surface, and turn the steering wheel to the straight ahead position while moving the vehicle.

Scheme 64

1. With the ignition switch in LOCK (0), connect the HDS to the data link connector (DLC) (A) under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, troubleshoot the DLC circuit (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513833-S41457160082012111600000) ).
4. Do the steering angle sensor center point writing in the VSA ADJUSTMENT with the HDS. NOTE: See the HDS Help menu for specific instructions.
5. Turn the ignition switch to LOCK (0).
6. Verity DTC 84 clears and does not return. If DTC 84 is indicated, do the appropriate troubleshooting.