SUBARU LEGACY 1997 Service Repair Manual

F: TROUBLE CODE 22 (FRONT RH)
G: TROUBLE CODE 24 (FRONT LH)
H: TROUBLE CODE 26 (REAR RH)
I: TROUBLE CODE 28 (REAR LH)
—ABNORMAL ABS SENSOR (ABNORMAL
ABS SENSOR SIGNAL)—
DIAGNOSIS:

Faulty ABS sensor signal (noise, irregular signal, etc.)

Faulty harness/connector
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1238
35
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8I1CHECK INSTALLATION OF ABS SEN-
SOR.
Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
: Are the ABS sensor installation bolts tight-
ened securely?
: Go to step8I2.
: Tighten ABS sensor installation bolts securely.
8I2CHECK INSTALLATION OF TONE
WHEEL.
Tightening torque:
13±3 N⋅m (1.3±0.3 kg-m, 9±2.2 ft-lb)
: Are the tone wheel installation bolts tight-
ened securely?
: Go to step8I3.
: Tighten tone wheel installation bolts securely.
G4M0700
8I3
CHECK ABS SENSOR GAP.
Measure tone wheel to pole piece gap over entire perim-
eter of the wheel.
: Is the gap within the specifications shown
in the following table?
SpecificationsFront wheel Rear wheel
0.9—1.4 mm
(0.035—0.055 in)0.7—1.2 mm
(0.028—0.047 in)
G4M0701
: Go to step8I4.
: Adjust the gap.
NOTE:
Adjust the gap using spacer (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
8I4
CHECK OSCILLOSCOPE.
: Is an oscilloscope available?
: Go to step8I5.
: Go to step8I6.
36
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8I5
CHECK ABS SENSOR SIGNAL.
1) Raise all four wheels of ground.
2) Turn ignition switch OFF.
3) Connect the oscilloscope to the connector (F1) or con-
nector (B100).
4) Turn ignition switch ON.
B4M1242A
5) Rotate wheels and measure voltage at specified fre-
quency.
NOTE:
When this inspection is completed, the ABS control mod-
ule sometimes stores the trouble code 29.
Connector & terminal
Trouble code 22 / (B100) No. 12 (+)—No. 13 ():
Trouble code 24 / (B100) No. 3 (+)—No.4():
Trouble code 26 / (F1) No. 4 (+)—No.5():
Trouble code 28 / (F1) No. 1 (+)—No.2():
Specified voltage: 0.12—1 V (When it is 20 Hz.)
: Is oscilloscope pattern smooth, as shown in
figure?
: Go to step8I9.
: Go to step8I6.
8I6CHECK CONTAMINATION OF ABS SEN-
SOR OR TONE WHEEL.
Remove disc rotor or drum from hub in accordance with
trouble code.
: Is the ABS sensor pole piece or the tone
wheel contaminated by dirt or other foreign
matter?
: Thoroughly remove dirt or other foreign matter.
: Go to step8I7.
8I7CHECK DAMAGE OF ABS SENSOR OR
TONE WHEEL.
: Are there broken or damaged in the ABS
sensor pole piece or the tone wheel?
: Replace ABS sensor or tone wheel.
: Go to step8I8.
37
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8I8
CHECK HUB RUNOUT.
Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step8I9.
: Repair hub.
B4M0806E
B4M1036C
8I9
CHECK RESISTANCE OF ABS SENSOR.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS sensor.
3) Measure resistance between ABS sensor connector ter-
minals.
Terminal
Front RH No. 1—No. 2:
Front LH No. 1—No. 2:
Rear RH No. 1—No. 2:
Rear LH No. 1—No. 2:
: Is the resistance between 0.8 and 1.2 kΩ?
: Go to step8I10.
: Replace ABS sensor.
B4M0818E
B4M1042C
8I10CHECK GROUND SHORT OF ABS SEN-
SOR.
Measure resistance between ABS sensor and chassis
ground.
Terminal
Front RH No. 1—Chassis ground:
Front LH No. 1—Chassis ground:
Rear RH No. 1—Chassis ground:
Rear LH No. 1—Chassis ground:
: Is the resistance more than 1 MΩ?
: Go to step8I11.
: Replace ABS sensor.
38
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

B4M1239A
8I11CHECK HARNESS/CONNECTOR
BETWEEN ABSCM AND ABS SENSOR.
1) Connect connector to ABS sensor.
2) Disconnect connector from ABSCM&H/U.
3) Measure resistance at ABSCM&H/U connector termi-
nals.
Connector & terminal
Trouble code 22 / (F49) No. 11—No. 12:
Trouble code 24 / (F49) No. 9—No. 10:
Trouble code 26 / (F49) No. 14—No. 15:
Trouble code 28 / (F49) No. 7—No. 8:
: Is the resistance between 0.8 and 1.2 kΩ?
: Go to step8I12.
: Repair harness/connector between ABSCM&H/U
and ABS sensor.
B4M1241A
8I12
CHECK GROUND SHORT OF HARNESS.
Measure resistance between ABSCM&H/U connector and
chassis ground.
Connector & terminal
Trouble code 22 / (F49) No. 11—Chassis ground:
Trouble code 24 / (F49) No. 9—Chassis ground:
Trouble code 26 / (F49) No. 14—Chassis ground:
Trouble code 28 / (F49) No. 7—Chassis ground:
: Is the resistance more than 1 MΩ?
: Go to step8I13.
: Repair harness/connector between ABSCM&H/U
and ABS sensor.
B4M1243A
8I13CHECK GROUND CIRCUIT OF
ABSCM&H/U.
Measure resistance between ABSCM&H/U and chassis
ground.
Connector & terminal
(F49) No. 23—GND:
: Is the resistance less than 0.5Ω?
: Go to step8I14.
: Repair ABSCM&H/U ground harness.
39
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8I14CHECK POOR CONTACT IN CONNEC-
TORS.
: Is there poor contact in connectors between
ABSCM&H/U and ABS sensor? FOREWORD [T3C1].>
: Repair connector.
: Go to step8I15.
8I15
CHECK SOURCES OF SIGNAL NOISE.
: Is the car telephone or the wireless trans-
mitter properly installed?
: Go to step8I16.
: Properly install the car telephone or the wireless
transmitter.
8I16
CHECK SOURCES OF SIGNAL NOISE.
: Are noise sources (such as an antenna)
installed near the sensor harness?
: Install the noise sources apart from the sensor
harness.
: Go to step8I17.
B4M1244A
8I17
CHECK SHIELD CIRCUIT.
1) Connect all connectors.
2) Measure resistance between shield connector and
chassis ground.
Connector & terminal
Trouble code 22 / (B100) No. 11—Chassis ground:
Trouble code 24 / (B100) No. 2—Chassis ground:
Trouble code 26 / Go to step 8I18.
Trouble code 28 / Go to step 8I18.
: Is the resistance less than 0.5Ω?
: Go to step8I18.
: Repair shield harness.
40
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8I18
CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM&H/U.
: Go to step8I19.
8I19CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary noise interference.
41
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

J: TROUBLE CODE 29
—ABNORMAL ABS SENSOR SIGNAL (ANY
ONE OF FOUR)—
DIAGNOSIS:

Faulty ABS sensor signal (noise, irregular signal, etc.)

Faulty tone wheel

Wheels turning freely for a long time
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1238
42
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8J1CHECK IF THE WHEELS HAVE TURNED
FREELY FOR A LONG TIME.
: Check if the wheels have been turned freely
for more than one minute, such as when the
vehicle is jacked-up, under full-lock corner-
ing or when tire is not in contact with road
surface.
: The ABS is normal. Erase the trouble code.
NOTE:
When the wheels turn freely for a long time, such as when
the vehicle is towed or jacked-up, or when steering wheel
is continuously turned all the way, this trouble code may
sometimes occur.
: Go to step8J2.
8J2
CHECK TIRE SPECIFICATIONS.
: Are the tire specifications correct?
: Go to step8J3.
: Replace tire.
8J3
CHECK WEAR OF TIRE.
: Is the tire worn excessively?
: Replace tire.
: Go to step8J4.
8J4
CHECK TIRE PRESSURE.
: Is the tire pressure correct?
: Go to step8J5.
: Adjust tire pressure.
8J5CHECK INSTALLATION OF ABS SEN-
SOR.
Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
: Are the ABS sensor installation bolts tight-
ened securely?
: Go to step8J6.
: Tighten ABS sensor installation bolts securely.
43
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8J6CHECK INSTALLATION OF TONE
WHEEL.
Tightening torque:
13±3 N⋅m (1.3±0.3 kg-m, 9±2.2 ft-lb)
: Are the tone wheel installation bolts tight-
ened securely?
: Go to step8J7.
: Tighten tone wheel installation bolts securely.
G4M0700
8J7
CHECK ABS SENSOR GAP.
Measure tone wheel to pole piece gap over entire perim-
eter of the wheel.
: Is the gap within the specifications shown
in the following table?
SpecificationsFront wheel Rear wheel
0.9—1.4 mm
(0.035—0.055 in)0.7—1.2 mm
(0.028—0.047 in)
G4M0701
: Go to step8J8.
: Adjust the gap.
NOTE:
Adjust the gap using spacer (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
8J8
CHECK OSCILLOSCOPE.
: Is an oscilloscope available?
: Go to step8J9.
: Go to step8J10.
8J9
CHECK ABS SENSOR SIGNAL.
1) Raise all four wheels of ground.
2) Turn ignition switch OFF.
3) Connect the oscilloscope to the connector (F1) or con-
nector (B100).
4) Turn ignition switch ON.
44
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light