1997 SUBARU LEGACY ECU

B4M0430
10C1
CHECK GENERATOR.
1) Start the engine.
2) Idle the engine.
3) Measure voltage between generator and chassis
ground.
: Terminal
Generator B terminal (+)—Chassis ground
():
Is voltage 10—15 V?
: Go to step10C2.
: Repair generator.
10C2
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Is there poor contact at battery terminal?
: Repair battery terminal.
: Go to step10C3.
10C3CHECK COMMUNICATION OF SELECT
MONITOR.
Using the select monitor, check whether communication to
other system (such as engine, AT, etc.) can be executed
normally.
: Are the name and year of the system dis-
played on the select monitor?
: Go to step10C4.
: Repair select monitor communication cable and
connector.
10C4CHECK INSTALLATION OF ABSCM CON-
NECTOR.
Turn ignition switch to OFF.
: Is ABSCM connector inserted into ABSCM
until the clamp locks onto it?
: Go to step10C5.
: Insert ABSCM connector into ABSCM until the
clamp locks onto it.
126
4-4cBRAKES [ABS 5.3 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 step10H5.
10H2CHECK ABS SENSOR MECHANICAL
TROUBLE.
: 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 next.
: Tighten ABS sensor installation bolts securely.
: 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 next step.
: Tighten tone wheel installation bolts securely.
G4M0700
1) Measure tone wheel-to-pole piece gap over entire
perimeter 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)
135
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

10H9CHECK ABS SENSOR MECHANICAL
TROUBLE.
: 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 next.
: Tighten ABS sensor installation bolts securely.
: 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 next step.
: Tighten tone wheel installation bolts securely.
G4M0700
1) Measure tone wheel-to-pole piece gap over entire
perimeter 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 next step.
: 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.
2) Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step10H10.
: Repair hub.
139
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

10L6CHECK ABS SENSOR MECHANICAL
TROUBLE.
: 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 next.
: Tighten ABS sensor installation bolts securely.
: 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 next step.
: Tighten tone wheel installation bolts securely.
G4M0700
1) Measure tone wheel to pole piece gap over entire
perimeter 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 next.
: 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.
: Is an oscilloscope available?
: Go to next step.
: Go to step 10).
2) Raise all four wheels of ground.
3) Turn ignition switch OFF.
4) Disconnect connector from ABS control module.
5) Disconnect connector cover from connector.

6) Connect connector to ABS control module.
7) Connect the oscilloscope to the ABS control module
connector in accordance with trouble code.
8) Turn ignition switch ON.
146
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

10M2
CHECK TIRE.
: Are the tire specifications correct?
: Go to next.
: Replace tire.
: Is the tire worn excessively?
: Replace tire.
: Go to next.
: Is the tire pressure correct?
: Go to step10M3.
: Adjust tire pressure.
10M3CHECK ABS SENSOR MECHANICAL
TROUBLE.
: 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 next.
: Tighten ABS sensor installation bolts securely.
: Tightening torque:
13±3 N⋅m (1.3±0.3 kg-m, 9±2.2 ft-lb)
Are the ABS sensor installation bolts tight-
ened securely?
: Go to next step.
: Tighten ABS sensor installation bolts securely.
G4M0700
1) Measure tone wheel to pole piece gap over entire
perimeter 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)
154
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M0962
V: 41 ECU
—ABNORMAL ABS CONTROL MODULE—
DIAGNOSIS:

Faulty ABSCM
TROUBLE SYMPTOM:

ABS does not operate.
10V1.Check ground circuit of ABSCM.
10V2.Check poor contact in connector between
battery, ignition switch and ABSCM.
10V3.Check sources of signal noise.
10V4.Check ABSCM.
WIRING DIAGRAM:
B4M0837



181
4-4cBRAKES [ABS 5.3 TYPE]
10. Diagnostics Chart with Select Monitor

B4M1240A
8E5
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 step8E6.
: Repair harness between ABSCM&H/U and ABS
sensor.
B4M1240A
8E6
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 step8E7.
: Repair harness between ABSCM&H/U and ABS
sensor.
8E7CHECK 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 step8E8.
: Tighten ABS sensor installation bolts securely.
31
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light

8E8CHECK 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 step8E9.
: Tighten tone wheel installation bolts securely.
G4M0700
8E9
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 step8E10.
: 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.
8E10
CHECK HUB RUNOUT.
Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step8E11.
: Repair hub.
32
4-4dBRAKES [ABS 5.3i TYPE]
8. Diagnostics Chart with Trouble Code by ABS Warning Light