1999 TOYOTA CAMRY ABS

BR3583
BR3582F00010
RotorSpeed Sensor
Magnet
To ECU
+V
±VHigh Speed
Low Speed
CoilNS
DI±514
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
749 Author: Date:
DTC31, 32, 33, 34Speed Sensor Circuit
CIRCUIT DESCRIPTION
The speed sensor detects wheel speed and sends the ap-
propriate signals to the ECU. These signals are used to control
the ABS system. The front and rear rotors each have 48 serra-
tions.
When the rotors rotate, the magnetic field emitted by the perma-
nent magnet in the speed sensor generates an AC voltage.
Since the frequency of this AC voltage changes in direct propor-
tion to the speed of the rotor, the frequency is used by the ECU
to detect the speed of each wheel.

DTC No.DTC Detecting ConditionTrouble Area
31, 32, 33, 34
Detection of any of conditions from 1. through 4.:
1. Vehicle speed is at 10 km/h (6 mph) or more and the
speed sensor signal circuit is open or short circuit con-
tinues for 15 sec. or more.
2. Momentary interruption of the speed sensor signal oc-
curs 7 times or more.
3. Vehicle speed is at 20 km/h (12mph) or more and inter-
ference on the speed sensor signal continues for 5 sec.
or more.
4. Open circuit condition of the speed sensor signal circuit
continues for 0.5 sec. or more.

Right front, left front, right rear, left rear speed sensor

Each speed sensor circuit

Speed sensor rotor
HINT:

DTC No. 31 is for the right front speed sensor.

DTC No. 32 is for the left front speed sensor.

DTC No. 33 is for the right rear speed sensor.

DTC No. 34 is for the left rear speed sensor.
Fail safe function:
If trouble occurs in the speed sensor circuit, the ECU cuts off current to the ABS solenoid relay and prohibits
ABS control.
DI1JM±02

F00116
Right Front
Speed Sensor
Left Front
Speed Sensor
Right Rear
Speed Sensor
Left Rear
Speed Sensor2
1A18
A19 12
1
2
2 1A18
A18
A18
A19
A19
A19ABS ECU
W
B
R
G
B
G RB WG R
IK2
IL1
ID1IK2
ID1 IL11
6
2
1
3
983
FR+
FR±
FL+
FL±
RR+
RR±
RL+
RL±Right Front
Speed Sensor
Left Front
Speed Sensor
Left Rear
Speed Sensor2
1A18
A19 12
1
2
2 1A18
A18
A18
A19
A19
A19ABS ECU
W
B
R
G
W
G RB WG R
IK2
IL1
ID1IK2
ID1 IL11
6
2
1
3
99
93
FR+
FR±
FL+
FL±
RR+
RR±
RL+
RL± 2
10
23
R
G22
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
DI±515
750 Author: Date:
WIRING DIAGRAM

BR3795
OK NG OK NG
OK NGOK NG
W04200
Normal Signal Waveform
1 V / Division2 m/s / DivisionGND
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
DI±517
752 Author: Date:
2 Check for open and short circuit in harness and connector between each speed
sensor and ECU (See page IN±31).
NG Repair or replace harness or connector.
OK
3 Check speed sensor installation.
CHECK:
Check the speed sensor installation.
OK:
The installation bolt is tightened properly and there is
no clearance between the sensor and steering
knuckle or rear axle carrier.
NG Replace speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI±493).
OK
4 Check speed sensor and sensor rotor serrations.
REFERENCE: INSPECTION USING OSCILLOSCOPE
PREPARATION:
(a) Remove the ABS ECU.
(b) Connect the oscilloscope to the terminals FR+, FL+, RR+
or RL+ and GND of the ABS ECU.
CHECK:
Drive the vehicle with about 30 km/h (19 mph), and check the
signal waveform.
OK Check and replace ABS ECU.
NG

R00948
R00947
DI±518
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
753 Author: Date:
5 Check sensor rotor and sensor tip.
Front:
PREPARATION:
Remove the front drive shaft (See page SA±17 or SA±26).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or foreign objects.
PREPARATION:
Remove the front speed sensor (See page BR±68).
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
Rear:
PREPARATION:
Remove the axle hub (See page SA±52).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth or foreign objects.
PREPARATION:
Remove the rear speed sensor (See page BR±71).
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
NG Replace sensor rotor or speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI±493).
OK
Check and replace ABS ECU.

± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
DI±519
754 Author: Date:
DTC 33, 34 Rear Speed Sensor Rotor Faulty
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
33, 34
The condition that the both rear side wheels' speed is
lower than the front wheels' speed at 20 km/h (12 mph) or
more for 20 sec. or more when the IG switch turns ON
and OFF , which is repeated in a sequence more than 8
times.

Rear axle hub

Right rear, left rear speed sensor

Rear speed sensor circuit
INSPECTION PROCEDURE
1 Check rear axle hub (See page SA±9).
NG Replace rear axle hub.
OK
2 Check rear speed sensor (See page DI±514).
NG Replace rear speed sensor.
OK
3 Check for open and short circuit in harness and connector between rear speed
sensor and ECU (See page IN±31).
NG Repair or replace harness and connector.
OK
Check and replace ABS ECU.
DI03L±03

F07156
Ignition
Switch
W24
AM1
IG1
B±YInstrument Panel J/B
19
1K
ECU±IG1JB±RJ/C
J12
C
CB±R13
A19ABS ECU
IG1
Instrument Panel J/B
21
1K
1B
AM1
B±R
FL Block
1
1
F4 F9
ALT
B±G
FL MAIN
Battery
IG A
Instrument
Panel Brace LH J11
Junction
ConnectorW±B
W±B12
A19
A1925GND1
GND2 DI±520
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
755 Author: Date:
DTC 41 IG Power Source Circuit
CIRCUIT DESCRIPTION
This is the power source for the ECU, hence the actuators.
DTC No.DTC Detecting ConditionTrouble Area
41
Condition 1. or 2. is detected:
1. Vehicle speed is at 3 km/h (1.9 mph) or more and ECU
terminal IG1 voltage is 9.5 V or less , which continues
for 10 sec. or more.
2. When IG1 terminal voltage is less than 9.5 V, there is
open circuit in the motor relay or in the solenoid relay, or
the solenoid circuit malfunction.

Battery

Charging system

Power source circuit
Fail safe function:
If trouble occurs in the power source circuit, the ECU cuts off current to the ABS solenoid relay and prohibits
ABS control.
WIRING DIAGRAM
DI03M±03

F07151
ON
(+)(±)
IG1GND
GND
F07152F07216
LOCK
(±) GND
GND(+)
DI±522
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
757 Author: Date:
3 Check voltage between terminals IG1 and GND of ABS ECU connector.
PREPARATION:
Remove ABS ECU with connectors still connected.
CHECK:
(a) Turn the ignition switch ON.
(b) Measure voltage between terminals IG1 and GND of ABS
ECU connector.
OK:
Voltage: 10 ± 14 V
OK Check and replace ABS ECU.
NG
4 Check continuity between terminals GND of ABS ECU connector and body
ground.
PREPARATION:
Disconnect the connector from the ABS ECU.
CHECK:
Measure resistance between terminal GND of ABS ECU con-
nector and body ground.
OK:
Resistance: 1 W or less
NG Repair or replace harness or connector.
OK
Check for open circuit in harness and connector between ABS ECU and ECU±IG fuse (See page
IN±31).

F00124
Battery MAIN B±GF4 F91
ALT FL Block
B±R STOP Instrument Panel J/B
1C1B4
7Stop Light
Switch
2G±W
1R 1S5J27 J28J/C
Light Failure
Sensor
J/C
J40
BL
BP W±BG±W
A195
STPABS ECU
R
G±R
High
Mounted
Stop
LightRight
Stop
LightLeft
Stop
Light
A 1Instrument
Panel J/B
G±R W
11R
2 4
G±W
G±R
W±B
W±B
W±B AAC
W±B W±BH10 R11
R9
H10R9
R11 2
122
5 5 G±W
1
2 7
Under the
Left Center
PillarBack Panel
Center
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM (DENSO Made)
DI±523
758 Author: Date:
DTC 49 Stop Light Switch Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
49
ABS ECU terminal IG1 voltage is 9.5 V to 18.5 V and ABS
is in non±operation, the open circuit of the stop light switch
circuit continues for 0.3 sec. or more.
Stop light switch

Stop light switch circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check that stop light lights up when brake pedal is depressed and turns off when brake pedal is released.
NG Repair stop light circuit (See page BE±37).
OK
DI03N±03