1997 SUBARU LEGACY sensor

B4M0945
E: TROUBLE CODE 21 FR. SS HARD
—ABNORMAL FRONT RH ABS SENSOR
(OPEN CIRCUIT OR INPUT VOLTAGE TOO
HIGH)—
B4M0946
F: TROUBLE CODE 23 FL. SS HARD
—ABNORMAL FRONT LH ABS SENSOR
(OPEN CIRCUIT OR INPUT VOLTAGE TOO
HIGH)—
B4M0947
G: TROUBLE CODE 25 RR. SS HARD
—ABNORMAL REAR RH ABS SENSOR
(OPEN CIRCUIT OR INPUT VOLTAGE TOO
HIGH)—
B4M0948
H: TROUBLE CODE 27 RL. SS HARD
—ABNORMAL REAR LH ABS SENSOR
(OPEN CIRCUIT OR INPUT VOLTAGE TOO
HIGH)—
99
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

DIAGNOSIS:

Faulty ABS sensor (Broken wire, input voltage too high)

Faulty harness connector
TROUBLE SYMPTOM:

ABS does not operate.
WIRING DIAGRAM:
B4M1238
100
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0922
10H1CHECK OUTPUT OF ABS SENSOR
USING SELECT MONITOR.
Read the ABS sensor output corresponding to the faulty
system in the select monitor function mode.
NOTE:
The select monitor display shows that the front right wheel
is rotating at 30 km/h.
: Does the speed indicated on the display
change in response to the speedometer
reading during acceleration/deceleration
when the steering wheel is in the straight-
ahead position?
: Go to step10H2.
: Go to step10H9.
10H2CHECK 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 step10H3.
: Tighten ABS sensor installation bolts securely.
10H3CHECK 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 step10H4.
: Tighten tone wheel installation bolts securely.
101
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

G4M0700
10H4
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 step10H5.
: Adjust the gap.
NOTE:
Adjust the gap using spacers (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
10H5
CHECK HUB RUNOUT.
Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step10H6.
: Repair hub.
10H6CHECK POOR CONTACT IN CONNEC-
TORS.
Turn ignition switch to OFF.
: Is there poor contact in connectors between
ABSCM&H/U and ABS sensor? FOREWORD [T3C1].>
: Repair connector.
: Go to step10H7.
10H7
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 step10H8.
102
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

10H8CHECK ANY OTHER TROUBLE CODES
APPEARANCE.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
NOTE:
Check harness and connectors between ABSCM&H/U and
ABS sensor.
B4M0806E
B4M1036C
10H9
CHECK ABS SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABS sensor.
3) Measure resistance of ABS sensor connector terminals.
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 step10H10.
: Replace ABS sensor.
B4M0807E
B4M1037C
10H10CHECK BATTERY SHORT OF ABS SEN-
SOR.
1) Disconnect connector from ABSCM&H/U.
2) Measure voltage 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 voltage less than 1 V?
: Go to step10H11.
: Replace ABS sensor.
103
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M0807E
B4M1037C
10H11CHECK BATTERY SHORT OF ABS SEN-
SOR.
1) Turn ignition switch to ON.
2) Measure voltage 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 voltage less than 1 V?
: Go to step10H12.
: Replace ABS sensor.
B4M1239A
10H12CHECK HARNESS/CONNECTOR
BETWEEN ABSCM&H/U AND ABS SEN-
SOR.
1) Turn ignition switch to OFF.
2) Connect connector to ABS sensor.
3) Measure resistance between ABSCM&H/U connector
terminals.
Connector & terminal
Trouble code 21 / (F49) No. 11—No. 12:
Trouble code 23 / (F49) No. 9—No. 10:
Trouble code 25 / (F49) No. 14—No. 15:
Trouble code 27 / (F49) No. 7—No. 8:
: Is the resistance between 0.8 and 1.2 kΩ?
: Go to step10H13.
: Repair harness/connector between ABSCM&H/U
and ABS sensor.
104
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

B4M1240A
10H13
CHECK BATTERY SHORT OF HARNESS.
Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
Trouble code 21 / (F49) No. 11 (+)—Chassis ground
():
Trouble code 23 / (F49) No. 9 (+)—Chassis ground
():
Trouble code 25 / (F49) No. 14 (+)—Chassis ground
():
Trouble code 27 / (F49) No. 7 (+)—Chassis ground
():
: Is the voltage less than 1 V?
: Go to step10H14.
: Repair harness between ABSCM&H/U and ABS
sensor.
B4M1240A
10H14
CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM&H/U connector and
chassis ground.
Connector & terminal
Trouble code 21 / (F49) No. 11 (+)—Chassis ground
():
Trouble code 23 / (F49) No. 9 (+)—Chassis ground
():
Trouble code 25 / (F49) No. 14 (+)—Chassis ground
():
Trouble code 27 / (F49) No. 7 (+)—Chassis ground
():
: Is the voltage less than 1 V?
: Go to step10H15.
: Repair harness between ABSCM&H/U and ABS
sensor.
10H15CHECK 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 step10H16.
: Tighten ABS sensor installation bolts securely.
105
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor

10H16CHECK 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 step10H17.
: Tighten tone wheel installation bolts securely.
G4M0700
10H17
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 step10H18.
: Adjust the gap.
NOTE:
Adjust the gap using spacers (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
10H18
CHECK HUB RUNOUT.
Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step10H19.
: Repair hub.
106
4-4dBRAKES [ABS 5.3i TYPE]
10. Diagnostics Chart with Select Monitor