Mitsubishi Galant. Manual — part 519

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-9

CIRCUIT OPERATION

•

A toothed ABS rotor generates a voltage pulse as
it moves across the pickup field of each wheel
speed sensor.

•

The amount of voltage generated at each wheel
is determined by the clearance between the ABS
rotor teeth and the wheel speed sensor, and by
the speed of rotation.

•

The wheel speed sensors transmit the frequency
of the voltage pulses and the amount of voltage
generated by each pulse to the ABS electronic
control unit (ABS-ECU).

•

The ABS hydraulic unit modulates the amount of
braking force individually applied to each wheel
cylinder.

ABS DTC SET CONDITIONS

•

DTCs 11, 12, 13, 14 are output when signal is not
input due to breakage of the (+) or (-) wire of one
or more of the four wheel-speed sensors. DTCs
21, 22, 23, 24 are output in the following cases:

•

Open circuit is not found but no input is received
by one or more of the four wheel-speed sensors
at 10 km/h (6 mph) or more.

•

Sensor output drops due to a malfunctioning
sensor or warped ABS rotor.

TROUBLESHOOTING HINTS (The most likely
causes for these DTCs to set are:)
DTC 11, 12, 13, 14

•

Malfunction of the wheel speed sensor

•

Damaged wiring harness or connector

•

Malfunction of the hydraulic unit (Integrated with
ABS-ECU)

DTC 21, 22, 23, 24

•

Malfunction of the wheel speed sensor

•

Damaged wiring harness and connector

•

Malfunction of the hydraulic unit (Integrated with
ABS-ECU)

•

Malfunction of the ABS rotor

•

Malfunction of the wheel bearing

•

Excessive clearance between the sensor and
ABS rotor

DIAGNOSIS

Required Special Tool:

•

MB991223: Harness Set

STEP 1. Check the wheel speed sensor installation.
Q: Is the wheel speed sensor bolted securely in place at

the front knuckle or the rear knuckle?
YES : Go to Step 2.
NO : Install it properly. Then go to Step 9. Refer to

P.35B-

49

.

AC003858

GLOVE BOX

AB

CONNECTOR: C-13

AC003859AB

CONNECTORS: D-10, D-12, D-15
(UNDER THE FLROOR)

D-10

D-15

D-12

AC000939

FRONT WHEEL
SPEED SENSOR

REAR WHEEL
SPEED SENSOR

AB

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-10

STEP 2. Check wheel speed sensor circuit at the ABS-ECU
connector A-03.
(1) Disconnect connector A-03 and measure at the harness

side.

(2) Measure the resistance between the ABS-ECU connector

terminals 1 and 3, 5 and 6, 19 and 20, 22 and 23.

Standard Value: 1.28

−−−−

1.92 k

Ω

Ω

Ω

Ω

Q: Is the resistance between terminals 1 and 2, 5 and 6, 19

and 20, 22 and 23 within the standard value?
YES : Go to Step 6.
NO : Go to Step 3. or 4. or 5.

STEP 3. Check the harness wires between ABS-ECU
connector A-03 and wheel speed sensor <front: LH>
connector A-22.
NOTE: After inspecting intermediate connector C-05, inspect
the wire. If intermediate connector C-05 is damaged, repair or
replace it. Refer to GROUP 00E, Harness Connector
Inspection

P.00E-2

. If the connector has been repaired or

replaced, go to Step 9.

Q: Are any harness wires between ABS-ECU connector A-

03 and wheel speed sensor <front: LH> connector A-22
damaged?
YES : Repair them and go to Step 9.
NO : Go to Step 7.

STEP 4. Check the harness wires between ABS-ECU
connector A-03 and wheel speed sensor <front: RH>
connector A-36.
Q: Are any harness wires between ABS-ECU connector A-

03 and wheel speed sensor <front: RH> connector A-36
damaged?
YES : Repair them and then go to Step 9.
NO : Go to Step 7.

AC003860

A-03 (HARNESS SIDE)

AB

AC003865 AB

CONNECTORS: A-03, A-22

A-22

A-03

AC003856AB

CONNECTOR: C-05

COMBINATION
METER

AC003891

A-03

A-36

CONNECTORS: A-03, A-36

AB

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-11

STEP 5. Check the harness wires between ABS-ECU
connector A-03 and wheel speed sensor connector D-12
<rear: LH> or D-10 <rear RH>.
NOTE: After inspecting intermediate connector C-13,D-15 or
D-16, inspect the wire. If intermediate connector C-13,D-15 or
D-16 is damaged, repair or replace it. Refer to GROUP 00E,
Harness Connector Inspection

P.00E-2

. If the connector has

been repaired or replaced, go to Step 9 .

Q: Are any harness wires between ABS-ECU connector A-

03 and wheel speed sensor connector D-12 <rear: LH>
or D-10 <rear RH> damaged?
YES : Repair them and then go to Step 9.
NO : Go to Step 7.

AC003695 AB

CONNECTOR: A-03

AC003866

D-10

D-12

CONNECTORS: D-10, D-12
(UNDER THE FLOOR)

AB

AC003858

GLOVE BOX

AB

CONNECTOR: C-13

AC003867AB

CONNECTOR: D-15
(UNDER THE FLOOR)

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-12

STEP 6. Check the wheel speed sensor output voltage.
Refer to

P.35B-42

.

Output Voltage:

•

When measured with a voltmeter: 42 mV or more

•

When measured with oscilloscope (maximum voltage): 200
mV or more

Q: Does the voltage meet the specification?

YES : Replace the hydraulic unit (integrated with ABS-ECU)

and then go to Step 9.

NO : Go to Step 7.

STEP 7. Check the wheel speed sensor or ABS rotor.
Refer to

P.35B-50

.If there is damaged in any of the check

items, replace the wheel speed sensor.
Check items:

•

Wheel speed sensor internal resistance

Standard value: 1.28

−−−−

1.92 k

Ω

Ω

Ω

Ω

•

Wheel speed sensor insulation resistance

Standard value: 100 k

Ω

Ω

Ω

Ω

•

Toothed ABS rotor check

Q: Is the wheel speed sensor or ABS rotor damaged?

YES : Replace it and then go to Step 9.
NO : Go to Step 8.

STEP 8. Check the wheel bearing.
Refer to GROUP 26, Front Hub Assembly

P.26-7

.

Refer to GROUP 27, Rear Axle Hub

P.27-6

.

Q: Is the wheel bearing damaged?

YES : Replace it and then go to Step 9.
NO : Go to Step 9.

STEP 9. Check the diagnostic trouble codes.

Q: Do the diagnostic trouble codes 11, 12, 13, 14, 21, 22, 23

and 24 reset?
YES : Go to Step 1.
NO : This diagnosis is complete.