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How to Troubleshoot the VSA System

How to Troubleshoot the VSA System 7938

VSA System Indicator
This system has seven indicators on the gauge control module.

Honda VSA System Indicator

When the system is OK, each indicator comes on for about 2 seconds after turning the vehicle to the ON mode, then it goes off.

When the system detects a problem, a DTC will set and depending upon the failure, the VSA modulator-control unit determines which indicator(s) will turn on. If the problem goes away (system returns to normal), the indicator(s) will be controlled in the following way depending upon the DTC that was set:

  • The indicator(s) will come on and stay on when turning the vehicle to the ON mode.
  • The indicator(s) will automatically go off.
  • The indicator(s) will go off after the vehicle is driven.

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

NOTE: If two or more wheel speed sensors fail, the brake system indicator (red) will come on.

  • VSA Indicator
    The VSA indicator comes on when the VSA function is lost.
  • The VSA indicator blinks when the VSA function is activating, or the clutch pedal stroke sensor zero point is not learned after replacing the VSA modulator-control unit or the clutch pedal.

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

Brake System Indicator (Amber)
The brake system indicator (amber) comes on, when the brake control system is lost.

Automatic Brake Hold System Indicator
The automatic brake hold system indicator comes on when the automatic brake hold system is turned ON by using the automatic brake hold switch.

Automatic Brake Hold Indicator
The automatic brake hold indicator comes on when the automatic brake hold function is activating.

Diagnostic Trouble Code (DTC)

  • The memory can hold all DTCs. However, when the same DTC is detected more than once, the more recent DTC is written over the earlier one. Therefore, when the same problem is detected repeatedly, it is memorized as a single DTC.
  • The DTCs are memorized in an EEPROM in the VSA modulator-control unit. Therefore, the memorized DTCs cannot be erased by disconnecting the 12 volt battery. Do the specified procedures to clear the DTCs.

Self-Diagnosis

  • Self-diagnosis can be classified into two categories:
  • 1.  Initial diagnosis: Done right after turning the vehicle to the ON mode and until the ABS, VSA, and brake system indicator (amber) go off.
  • 2.  Regular diagnosis: Done right after the initial diagnosis until turning the vehicle to the OFF (LOCK) mode.
  • When the system detects a problem, the VSA modulator-control unit shifts to fail-safe mode.

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

Pump Motor
The pump motor operates when the VSA modulator-control unit is functioning.
The VSA modulator-control unit checks the pump motor operation when the vehicle is started and does it’s first initial acceleration.

Brake Fluid Replacement/Air Bleeding
Brake fluid replacement and air bleeding procedures are identical to the procedures used on vehicles without the VSA system.

How to Troubleshoot DTCs
The troubleshooting procedures assume that the cause of the problem is still present and the ABS, VSA, and/or brake system indicator (amber) are still on. Following a troubleshooting procedure for a DTC that has been cleared but does not reset can result in incorrect diagnosis.

  1. Question the customer about the conditions when the problem occurred, and try to reproduce the same conditions for troubleshooting. Find out when the ABS, VSA, and/or brake system indicator (amber) came on, such as during activation, after activation, when the vehicle was traveling at a certain speed, etc. If necessary, have the customer demonstrate the concern.
  2. When the ABS, VSA, or brake system indicator (amber) does not come on during the test-drive, but troubleshooting is done based on the DTC, check for loose connectors, poor contact of the terminals, etc. in the circuit indicated by the DTC.
  3. After troubleshooting, or the repairs are done, clear the DTCs, and test-drive the vehicle under the same conditions that originally set the DTCs. Make sure the ABS, VSA and brake system indicator (amber) do not come on.

Intermittent Failures
The term ‘‘intermittent failure’’ means a system may have had a failure, but it checks OK now. If you cannot reproduce the condition, check for loose connections and terminals. Also check ground and power connections related to the circuit that you are troubleshooting.

How to Use the HDS (Honda Diagnostic System)
NOTE: Make sure the 12 volt battery is in good condition and fully charged.

  1. If the system indicators stay on, connect the HDS to the data link connector (DLC) .
  2. Turn the vehicle to the ON mode.
  3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, go to the DLC circuit troubleshooting.
  4. Check the diagnostic trouble code (DTC) for all systems, troubleshoot the powertrain DTCs first. Then refer to the indicated DTC’s troubleshooting, and do the appropriate troubleshooting procedure.

NOTE:

  • Freeze data indicates the VSA conditions when the first system malfunction that activated the indicator was detected.
  • The HDS can read the DTC, the freeze data, the current data, and other system data.
  • For specific operations, refer to the HDS Help menu.

How to Retrieve DTCs

  1. With the vehicle in OFF (LOCK) mode, connect the HDS to the data link connector (DLC).
  2. Turn the vehicle to the ON mode.
  3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, go to the DLC circuit troubleshooting.
  4. Follow the prompts on the HDS to display the DTC(s) on the screen. After determining the DTC, refer to the DTC troubleshooting. Do the all systems DTC check, and troubleshoot any powertrain DTCs first.
  5. Turn the vehicle to the OFF (LOCK) mode.

How to Clear DTCs

  1. With the vehicle in OFF (LOCK) mode, connect the HDS to the data link connector (DLC).
  2. Turn the vehicle to the ON mode.
  3. Make sure the HDS communicates with the vehicle and the VSA modulator-control unit. If it does not, go to the DLC circuit troubleshooting.
  4. Clear the DTC(s) by following the screen prompts on the HDS.
  5. Turn the vehicle to the OFF (LOCK) mode.

How to Troubleshoot Circuit at the VSA Modulator-Control Unit Connectors
Connect one side of the patch cord (A) terminals to a commercially available digital multimeter (B), and connect the other side of the patch cord terminals to a commercially available banana jack (C).

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