Honda Civic. Manual — part 1093

3. Check the BRAKE SWITCH in the VSA DATA LIST with the HDS while

moving the brake pedal.

Does it indicate ON when the pedal is pressed, and OFF when the pedal is
released?

YES -Intermittent failure, the system is OK at this time.

NO -Go to step 4.

4. Check the BRAKE SWITCH in the VSA DATA LIST with the HDS, and

disconnect the brake pedal position switch 4P connector.

Does the indicator change from ON to OFF?

YES -Replace the brake pedal position switch (see BRAKE PEDAL AND
BRAKE PEDAL POSITION SWITCH ADJUSTMENT ).

NO -Go to step 5.

5. Turn the ignition switch to LOCK (0).
6. Short the SCS line with the HDS.
7. Disconnect ECM connector A (44P).
8. Turn the ignition switch ON (II).
9. Measure voltage between brake pedal position switch 4P connector terminal

No. 2 and body ground.

Fig. 44: Measuring Voltage Between Brake Pedal Position Switch 4P

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

Connector Terminal No. 2 And Body Ground

Is there 0.1 V or more?

YES -Repair short to power in the wire between the ECM and the brake pedal
position switch.

NO -Substitute a known-good ECM, then go to step 1 and recheck. If DTCs
are not indicated, replace the original ECM (see ECM REPLACEMENT ).

DTC 71-21: RIGHT-FRONT OR LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-22: LEFT-FRONT OR RIGHT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-23: RIGHT-FRONT AND RIGHT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-24: LEFT-FRONT AND LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-25: RIGHT-FRONT AND LEFT-FRONT DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-26: RIGHT-REAR AND LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-27: RIGHT-FRONT OR LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-28: LEFT-FRONT OR RIGHT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-29: RIGHT-FRONT AND RIGHT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-2A: LEFT-FRONT AND LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-2B: RIGHT-FRONT AND LEFT-FRONT DIFFERENT DIAMETER TIRE MALFUNCTION;
DTC 71-2C: RIGHT-REAR AND LEFT-REAR DIFFERENT DIAMETER TIRE MALFUNCTION

DTC REFERENCE

NOTE:

The DTC will be indicated when the vehicle has a different
diameter tire(s) compared to the other tire(s).

DTC

Sectional

Note

71-21

Right-front or left-rear

71-22

Left-front or right-rear

71-23

Right-front and right-rear

71-24

Left-front and left-rear

71-25

Right-front and left-front

71-26

Right-rear and left-rear

71-27

Right-front or left-rear

71-28

Left-front or right-rear

71-29

Right-front and right-rear

71-2A

Left-front and left-rear

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

1. Check the tires for proper inflation (see WHEEL ALIGNMENT ).
2. Turn the ignition switch ON (II).
3. Clear the DTC with the HDS.
4. Turn the ignition switch to LOCK (0).
5. Test-drive the vehicle.
6. Check for DTCs with the HDS.

Is DTC 71-21, 71-22, 71-23, 71-24, 71-25, 71-26, 71-27, 71-28, 71-29, 71-2A,
71-2B, or 71-2C indicated?

YES -Replace all four tires with the proper size (see WHEEL
ALIGNMENT ).

NO -Intermittent failure, the system is OK at this time.

DTC 81-XX*: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION

* : Subcode (Except DTC 81-11,81-3D, 81-3E, 81-51, 81-52,81-53,81-54,81-55,
81-56,81-57,81-58, and 81-59)

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0), then turn it ON (II) again.
4. Check for DTCs with the HDS.

Is DTC 81-xx indicated?

YES -If the DTC 81-11,81-3D,81-3E, 81-51, 81-52, 81-53, 81-54, 81-55, 81-
56, 81-57,81-58, or 81-59 is indicated at the same time, do the DTC 81-11, 81-
52,81-54,81-56, or 81-58 troubleshooting (see DTC 81-xx*: Central
Processing Unit (CPU) Internal Circuit Malfunction ), DTC 81-51,81-
53,81-55, or 81-57 troubleshooting (see DTC 81-51: Central Processing Unit
(CPU) Internal Circuit Malfunction; DTC 81-53: Central Processing Unit

71-2B

Right-front and left-front

71-2C

Right-rear and left-rear

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)

(CPU) Internal Circuit Malfunction; DTC 81-55: Central Processing Unit
(CPU) Internal Circuit Malfunction; DTC 81-57: Central Processing Unit
(CPU) Internal Circuit Malfunction ), or DTC 81-3D, 81-3E, or 81-59
troubleshooting (see DTC 81-3D: Central Processing Unit (CPU) Internal
Circuit Malfunction; DTC 81-3E: Central Processing Unit (CPU) Internal
Circuit Malfunction; DTC 81-59: Central Processing Unit (CPU) Internal
Circuit Malfunction ). If DTC 81-11, 81-3D, 81-3E, 81-51, 81-52, 81-53, 81-
54, 81-55, 81-56, 81-57, 81-58, or 81-59 is not indicated. Replace the VSA
modulator-control unit (see VSA MODULATOR-CONTROL UNIT
REMOVAL AND INSTALLATION ).

NO -Intermittent failure, the system is OK at this time.

DTC 81-11: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-
52: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-54:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-56:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-58:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Test-drive the vehicle.
4. Check for DTCs with the HDS.

Is DTC 81-11, 81-52, 81-54, 81-56, or 81-58 indicated?

YES -Replace the VSA modulator-control unit (see VSA MODULATOR-
CONTROL UNIT REMOVAL AND INSTALLATION ).

NO -Intermittent failure, the system is OK at this time.

DTC 81-51: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-
53: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-55:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-57:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.

2008 Honda Civic GX

2006-08 BRAKES VSA System - Civic (All Except Hybrid)