sensor SUBARU LEGACY 1996 Service Repair Manual

D: 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.
8D1.Check if the wheels have turned freely for a
long time.
8D2.Check tire.
8D3.Check ABS sensor mechanical trouble.
8D4.Check ABSCM.



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4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

8D2
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 step8D3.
: Adjust tire pressure.
8D3CHECK 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)
44
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

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.
8) Turn ignition switch ON.
B4M0816A
9) 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.
TROUBLE CODE / Connector & terminal:
(F49) No. 14 (+)—No. 15 () (Front RH)
(F49) No. 49 (+)—No. 19 () (Front LH)
(F49) No. 18 (+)—No. 46 () (Rear RH)
(F49) No. 16 (+)—No. 17 () (Rear LH)
Specified voltage: 0.12—1 V (When it is 20 Hz.)
: Is oscilloscope pattern smooth, as shown in
figure?
: Go to step8D4.
: Go to next step.
45
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

10) Remove disc rotor from hub.
: 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 next.
: Are there broken or damaged teeth in the
ABS sensor pole piece or the tone wheel?
: Replace ABS sensor or tone wheel.
: Go to next step.
11) Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step8D4.
: Repair hub.
8D4
CHECK ABSCM.
1) Turn ignition switch to OFF.
2) Connect all connectors.
3) Erase the memory.
4) Perform inspection mode.
5) Read out the trouble code.
: Is the same trouble code as in the current
diagnosis still being output?
: Replace ABSCM.
: Go to next.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
46
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0838A
8G1
CHECK GROUND CIRCUIT OF ABSCM.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM.
3) Measure resistance between ABSCM and chassis
ground.
: Connector & terminal
(F49) No. 1—Chassis ground
(F49) No. 55—Chassis ground
Is resistance less than 0.5Ω?
: Go to step8G2.
: Repair ABSCM ground harness.
8G2CHECK POOR CONTACT IN CONNEC-
TORS BETWEEN BATTERY, IGNITION
SWITCH AND ABSCM.
: Is there poor contact in connectors between
battery, ignition switch and ABSCM?
: Repair connector.
: Go to step8G3.
8G3
CHECK SOURCES OF SIGNAL NOISE.
: Is the car telephone or the wireless trans-
mitter properly installed?
: Go to next.
: Properly install the car telephone or the wireless
transmitter.
: Are noise sources (such as an antenna)
installed near the sensor harness?
: Install the noise sources apart from the sensor
harness.
: Go to step8G4.
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4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

J: TROUBLE CODE 46
—ABNORMAL G SENSOR POWER SUPPLY
VOLTAGE—
DIAGNOSIS:

Faulty G sensor power supply voltage
TROUBLE SYMPTOM:

ABS does not operate.
8J1.Check G sensor.
8J2.Check ground short of G sensor.
8J3.Check short of harness between ABSCM and
G sensor.
8J4.Check ground short of harness.
8J5.Check battery short of harness.
8J6.Check poor contact in connector between
ABSCM and G sensor.
8J7.Check ABSCM.






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4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

WIRING DIAGRAM:
B4M1047
B4M0851B
8J1
CHECK G SENSOR.
1) Turn ignition switch to OFF.
2) Remove console box.
3) Disconnect connector from G sensor.
4) Measure resistance of G sensor.
: Connector & terminal
To (P11) No. 1—No. 3
Is resistance 50±8 kΩ?
: Go to step8J2.
: Replace G sensor.
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4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0852B
8J2
CHECK GROUND SHORT OF G SENSOR.
Measure resistance between G sensor and bracket.
: Connector & terminal
To (P11) No. 3—Bracket
Is resistance more than 1 MΩ?
: Go to step8J3.
: Replace G sensor.
B4M0853A
8J3CHECK SHORT OF HARNESS BETWEEN
ABSCM AND G SENSOR.
1) Disconnect connector from ABSCM.
2) Measure resistance between ABSCM connector termi-
nals.
: Connector & terminal
(F49) No. 45—No. 8
Is resistance more than 1 MΩ?
: Go to step8J4.
: Repair harness between ABSCM and G sensor.
B4M0854A
8J4
CHECK GROUND SHORT OF HARNESS.
Measure resistance between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 8—Chassis ground
(F49) No. 45—Chassis ground
Is resistance more than 1 MΩ?
: Go to step8J5.
: Repair harness between ABSCM and G sensor.
73
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

B4M0855A
8J5
CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 8 (+)—Chassis ground ()
(F49) No. 45 (+)—Chassis ground ()
Is voltage 0 V?
: Go to next step.
: Repair harness between ABSCM and G sensor.
3) Turn ignition switch to OFF.
4) Measure voltage between ABSCM and chassis ground.
: Connector & terminal
(F49) No. 8 (+)—Chassis ground ()
(F49) No. 45 (+)—Chassis ground ()
Is voltage 0 V?
: Go to step8J6.
: Repair harness between ABSCM and chassis
ground.
8J6CHECK POOR CONTACT IN CONNEC-
TOR BETWEEN ABSCM AND G SENSOR.
: Is there poor contact in connectors between
ABSCM and G sensor?
: Repair connector.
: Go to step8J7.
8J7
CHECK ABSCM.
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.
: Go to next.
: Are other trouble codes being output?
: Proceed with the diagnosis corresponding to the
trouble code.
: A temporary poor contact.
74
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code

N: TROUBLE CODE 56
—ABNORMAL G SENSOR OUTPUT
VOLTAGE—
DIAGNOSIS:

Faulty G sensor output voltage
TROUBLE SYMPTOM:

ABS does not operate.
8N1.Check all four wheels for free turning.
8N2.Check specifications of ABSCM.
8N3.Check input voltage of G sensor.
8N4.Check broken wire in G sensor output harness
and ground harness.
8N5.Check ground short in G sensor output
harness.
8N6.Check battery short of harness.
8N7.Check G sensor.
8N8.Check poor contact in connector between
ABSCM and G sensor.
8N9.Check ABSCM.








105
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code