ECU TOYOTA RAV4 1996 Service Repair Manual

1999-2000 BRAKES
Anti-Lock - RAV4
DESCRIPTION
Anti-Lock Brake System (ABS) consists of hydraulic actuator, solenoids, pump motor, ABS Electronic Control
Unit (ECU), relays, deceleration sensor (4WD) and wheel speed sensors. See Fig. 1
.
An ABS warning light is located on the instrument cluster. Warning light comes on for 3 seconds as a bulb test
when ignition is turned on. A primary check is performed after each engine start and initial vehicle speed
exceeds 6 MPH. An actuator noise is heard as vehicle is started or as speed exceeds 6 MPH. This is normal.
Anti-lock systems remains active until vehicle speed drops below 3 MPH.

1999 Toyota RAV4
1999-2000 BRAKES Anti-Lock - RAV4

1999 Toyota RAV4
1999-2000 BRAKES Anti-Lock - RAV4
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23 Open/Shorted RR Solenoid, Defective ABS
Actuator
24 Open/Shorted LR Solenoid, Defective ABS
Actuator
31 (2) Malfunction In RF Speed Sensor Signal
32 (2) Malfunction In LF Speed Sensor Signal
33 (2) Malfunction In RR Speed Sensor Signal
34 (2) Malfunction In LR Speed Sensor Signal
37 (3) One Tire Is Different Size Than The Others
41 Excessively Low/High Battery Voltage
43 (4) Deceleration Sensor Malfunction (Constant
Output)
44 (4) Open/Short In Deceleration Sensor Circuit
45 (5) Deceleration Sensor Malfunction
49 (4) Open In Stoplight Switch Circuit
51 Pump Motor Locked Up, Open Ground
Circuit
Speed Sensor-Related DTCs (6)
71 RF Speed Sensor Signal Low Voltage
72 LF Speed Sensor Signal Low Voltage
73 RR Speed Sensor Signal Low Voltage
74 LR Speed Sensor Signal Low Voltage
75 RF Speed Sensor Abnormal Change In
Output Voltage
76 LF Speed Sensor Abnormal Change In
Output Voltage
77 RR Speed Sensor Abnormal Change In
Output Voltage
78 LR Speed Sensor Abnormal Change In
Output Voltage
79 (4) Deceleration Sensor Faulty
(1)For ABS ECU DTCs, connect jumper wire between terminals Tc and E1 of DLC1.
(2)To clear DTC, either drive vehicle over 12 MPH for 30 seconds or more, or use procedure to clear
DTC. See CLEARING DIAGNOSTIC TROUBLE CODES
.
(3)2WD models.
(4)4WD models.
(5)4WD 2 door models.
(6)For speed sensor DTCs, connect jumper wire between terminals Ts and E1 of DLC1. See SPEED

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per second. If ABS light does not blink, go to ABS WARNING LIGHT. If ABS warning light blinks,
go to next step.
3. Drive vehicle straight ahead above 28 MPH for several seconds. Stop vehicle. Jumper terminals Tc and
E
1 of DLC1. See Fig. 2 . If all sensors are okay, a normal DTC is displayed (ABS warning light blinks 2
times a second). If a malfunction is detected, ABS warning light will begin to flash a 2-digit DTC. First
number of blinks will equal first digit in a DTC. After a 1.5-second pause, second number of blinks will
equal second digit in a DTC.
4. If 2 or more DTCs are stored, there will be a 2.5-second pause between each DTC. After all DTCs are
flashed, there will be a 4 second pause and all DTCs will repeat.
5. Record DTCs. Turn ignition off. Repair as necessary. See DTC DEFINITIONS
. Remove jumper wire
from DLC1. Clear DTCs. See CLEARING DTCS
.
ABS WARNING LIGHT
Circuit Description
If ABS ECU detects a system malfunction, ABS ECU illuminates ABS warning light while at the same time
prohibiting ABS control. At this time, ABS ECU records a DTC in memory. After removing short pin from
DLC1, connecting terminals Tc and E
1 of DLC1 causes ABS warning light to blink and output a DTC. See Fig.
2 .
Diagnostic Procedure
1. If ABS warning light stays on, go to step 3 . If ABS warning light does not illuminate, check fuse, light
bulb and wiring. Repair or replace as necessary. If bulb is okay, diagnose combination meter (instrument
panel). See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If no
problems were found, go to next step.
2. Check ABS control relay. See SOLENOID RELAY SECTION
under ABS CONTROL RELAY under
COMPONENT TESTS. Replace as necessary. If ABS control relay is okay, go to next step.
3. Retrieve DTCs. See RETRIEVING DTCS
under DIAGNOSIS & TESTING. If DTC is present, perform
appropriate test under DIAGNOSTIC TESTS. If DTC is not present, and ABS warning light goes off
when short pin is removed, go to next step. If ABS warning light does not turn off, check for short circuit
in wiring harness between ABS warning light, DLC1 and ABS ECU. Repair as necessary. See WIRING
DIAGRAMS .
4. Check ABS control relay. See SOLENOID RELAY SECTION
under ABS CONTROL RELAY under
COMPONENT TESTS. Replace relay as necessary. If relay is okay, check for short circuit in wiring
harness between DLC1 and ABS control relay. Repair as necessary. See WIRING DIAGRAMS
.
TC TERMINAL
Circuit Description
Connecting terminals Tc and E1 of DLC1 causes ABS warning light to blink and output a DTC. See Fig. 2 .
Diagnostic Procedure

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Turn ignition on. Measure voltage between terminals Tc and E1of DLC1. If voltage is 10-14 volts, circuit is
okay. If ABS warning light does not blink even after terminals are connected, malfunction may exist in ABS
ECU. If voltage is not 10-14 volts, check for open or short circuit in wiring harness between ABS actuator and
DLC1, or between ground and DLC1. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is
okay, replace ABS ECU.
TS TERMINAL
Circuit Description
Sensor check circuit detects abnormalities in speed sensor signal which cannot be detected when checking for
DTCs. Connecting terminals Ts and E
1 of DLC1 in engine compartment starts DTC check. See Fig. 2 .
Diagnostic Procedure
Turn ignition on. Measure voltage between terminals Ts and E1 of DLC1. If voltage is 10-14 volts, circuit is
okay. If ABS warning light does not blink even after terminals are connected, malfunction may exist in ABS
ECU. If voltage is not 10-14 volts, check for open or short circuit in wiring harness between ABS ECU and
DLC1, or between ground and DLC1. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is
okay, replace ABS ECU.
ABS ECU PIN VOLTAGES
ABS circuits and harness can be tested by backprobing ABS ECU connectors and comparing measured voltages
with ABS ECU standard values chart. See Fig. 3
.

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1999-2000 BRAKES Anti-Lock - RAV4
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Fig. 3: ABS ECU Standard Values Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
SYMPTOM DIAGNOSIS
If a normal DTC is displayed during DTC check but problem still occurs, check circuits for each problem
symptom in order given in SYMPTOM DIAGNOSIS
, then see specified procedure or appropriate test under
DIAGNOSIS & TESTING
, DIAGNOSTIC TESTS or COMPONENT TESTS .
SYMPTOM DIAGNOSIS
SymptomCircuitCircuit, DTC Or Procedure
Check DTC, Confirm Normal DTC
RETRIEVING DIAGNOSTIC TROUBLE

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SYMPTOM TESTS
ABS LIGHT ON: ABS ECU MALFUNCTION
Circuit Description
This circuit is the power source for ABS ECU and actuator.
DTC Detecting Condition
If voltage at ABS ECU terminal IG1 remains more than 17 volts, this DTC will set. If a malfunction occurs in
power source circuit, ABS ECU cuts off current to ABS control relay and prohibits ABS control.
Diagnostic Procedure
1. Retrieve DTCs. See RETRIEVING DTCS under DIAGNOSIS & TESTING. If DTC is output using
ABS warning light, perform appropriate test under DIAGNOSTIC TESTS
. If ABS warning light does
not operate normally, go to next step. If ABS warning light operates normally (lights blink 2 times per
second and no DTCs are present), check ABS control (solenoid) relay. See SOLENOID RELAY
SECTION under ABS CONTROL RELAY under COMPONENT TESTS. Check for short circuit in
ABS Inoperative (1)
Is OutputCODES
IG Power Source CircuitDTC 41
Speed Sensor CircuitDTCS 31, 32, 33 & 34: SPEED SENSOR
CIRCUIT
Check ABS Actuator (2) ACTUATOR CHECK
ABS Operates
Intermittently
(1)
Check DTC, Confirm Normal DTC
Is OutputRETRIEVING DIAGNOSTIC TROUBLE
CODES
Speed Sensor CircuitDTCS 31, 32, 33 & 34: SPEED SENSOR
CIRCUIT
Stoplight Switch CircuitDTC 49: STOPLIGHT SWITCH
CIRCUIT
Check ABS Actuator (2) ACTUATOR CHECK
ABS Warning Light
AbnormalABS Warning Light CircuitABS WARNING LIGHT
ABS ECUABS LIGHT ON: ABS ECU
MALFUNCTION
Unable To Perform
DTC Check
(1)
ABS Warning Light CircuitABS WARNING LIGHT
Tc Terminal CircuitTc TERMINAL
Unable To Do Speed
Sensor DiagnosticsTs Terminal CircuitTs TERMINAL
ABS ECUABS LIGHT ON: ABS ECU
MALFUNCTION
(1)If all circuits check okay and problem is still occurring, replace ABS ECU.
(2)If actuator check is abnormal, check for hydraulic leakage, perform visual inspection.

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1999-2000 BRAKES Anti-Lock - RAV4
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wiring harness between ABS control relay and DLC1. Repair or replace as necessary. See WIRING
DIAGRAMS .
2. If ABS warning light is on, go to next step. If ABS warning light is off, check for open or short circuit in
wiring harness between ECU-IG fuse and ABS ECU. Repair as necessary. See WIRING DIAGRAMS
.
3. Start engine and check charging system voltage. If voltage is 10-16 volts, go to next step. If voltage is not
10-16 volts, diagnose charging system. Repair as necessary.
4. Turn ignition off. Disconnect appropriate ABS ECU connector supporting IG1 terminal. See Fig. 3
. Turn
ignition switch to ON position. Ensure ABS warning light turns off. If light turns off, replace ABS ECU.
If light does not turn off, check for short circuit in wiring harness between combination meter (instrument
panel) and ABS ECU, or between combination meter and DLC1. Repair as necessary. See WIRING
DIAGRAMS .
DIAGNOSTIC TESTS
DTC 11 & DTC 12: ABS CONTROL (SOLENOID) RELAY CIRCUIT
Circuit Description
This relay supplies power to each ABS solenoid. After ignition switch is turned to ON position, if initial check
is okay, this relay turns on. If malfunction occurs in ABS control relay circuit, ABS ECU cuts off current to
ABS control relay and prohibits ABS control.
DTC Detecting Condition
Detection of following conditions may set DTC 11 or DTC 12 if condition occurs for .2 seconds or more:
If voltage at ABS control relay connector terminal A9-1 is less than 1.5 volts and voltage at connector
terminal A9-5 is zero volts, DTC 11 may set.
If voltage at ABS control relay connector terminal A9-1 is 10-14 volts and voltage at connector terminal
A9-5 is 10-14 volts, DTC 12 may set.
Diagnostic Procedure
1. Disconnect ABS control relay 6-pin connector A9, located in engine compartment at front of vehicle. See
Fig. 1
. Measure voltage between connector terminals A9-2 and A9-6. See Fig. 4 . If voltage is 10-14
volts, go to next step. If voltage is not 10-14 volts, repair wiring harness between ground, battery and
ABS control relay.
2. Measure resistance between ABS control relay terminal A9-5 and appropriate ABS ECU terminals. See
ABS ECU
-TO-ACTUATOR CIRCUIT IDENTIFICATION/RESISTANCE VALUES . See Fig. 3 .
If resistance on every circuit is between 26-40 ohms, go to next step. If resistance is not as specified,
check for open or short circuit in appropriate wiring between ABS control relay, ABS actuator and ABS
ECU. See WIRING DIAGRAMS
. Repair as necessary. If wiring is okay, replace ABS actuator.
ABS ECU-TO-ACTUATOR CIRCUIT IDENTIFICATION/RESISTANCE VALUES
CircuitABS ECU
Connector/TerminalWire Color

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1999-2000 BRAKES Anti-Lock - RAV4
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3. Check ABS control relay. See SOLENOID RELAY SECTION under ABS CONTROL RELAY under
COMPONENT TESTS. Replace as necessary. If ABS control relay is okay, go to next step.
4. Check for open or short circuit in wiring harness between ABS control relay and ABS ECU. Repair as
necessary. See WIRING DIAGRAMS
. If circuit is okay, go to next step.
5. Clear DTCs and then recheck for DTCs. See RETRIEVING DTCS
under DIAGNOSIS & TESTING. If
same DTC is output after DTC is cleared, check contact condition of each connection. Repair as
necessary. If connections are okay, replace ABS ECU. See ABS ECU
under REMOVAL &
INSTALLATION.
Fig. 4: Testing ABS Control (Solenoid) Relay Power/Ground Circuits

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
DTC 13 & DTC 14: ABS CONTROL (MOTOR) RELAY CIRCUIT
Circuit Description
ABS control relay supplies power to ABS pump motor. While ABS is activated, ABS ECU switches ABS
control relay on and operates ABS pump motor. If malfunction occurs in ABS control relay circuit, ABS ECU
cuts off current to ABS control rela
y and prohibits ABS control.
SRLRA17-14Brown/Red
SRLHA17-15Brown/White
SRRRA16-12Green/Yellow
SRRHA16-11Green/Black
SFLRA16-6Blue/White
SFLHA16-5Blue/Red
SFRRA17-1Red/Green
SFRHA17-2Red/White

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DTC Detecting Condition
Detection of any of the following conditions may set DTC 13 or DTC 14 if condition occurs for .2 seconds or
more:
If voltage at ABS control relay connector terminal A8-4 is less than 1.5 volts, and voltage at connector
terminal A8-2 is zero volts, DTC 13 may set.
If voltage at ABS control relay connector terminal A8-4 is 10-14 volts, and voltage at connector terminal
A8-2 is 10-14 volts, DTC 14 may set.
Diagnostic Procedure
1. Disconnect ABS control relay connector A8, located in engine compartment at front of vehicle. See Fig.
1 . Measure voltage between ground and motor relay connector terminal A8-1. See Fig. 5 . If voltage is
10-14 volts, go to next step. If voltage is not 10-14 volts, repair wiring harness between battery and motor
relay. See WIRING DIAGRAMS
.
2. Disconnect 2 ABS actuator connectors. Check for continuity on Blue/Red wire between ABS actuator
connector terminal A7-2 and ABS control relay connector terminal A8-2. Also check for continuity on
Blue/Red wire between ABS actuator connector terminal A7-3 and ABS ECU connector terminal A16-
10. See Fig. 5
. Continuity should exist. If continuity is not present on either wire, repair open circuit on
affected wire between ABS control relay and ABS ECU. If continuity is present on both wires, go to next
step.
3. Check resistance between ABS actuator terminals A7-2 and A7-3. Resistance should be 26-40 ohms. If
resistance is as specified, go to next step. If resistance is not as specified, replace ABS actuator.
4. Check ABS control relay. See MOTOR RELAY SECTION
under ABS CONTROL RELAY under
COMPONENT TESTS. Replace relay as necessary. If relay tests okay, go to next step.
5. Check for open or short circuit in wiring harness between ABS control relay and ABS ECU. Repair as
necessary. See WIRING DIAGRAMS
. If circuit is okay, go to next step.
6. Clear DTCs and then recheck for DTCs. See RETRIEVING DTCS
under DIAGNOSIS & TESTING. If
same DTC is output after DTC is cleared, check contact condition of each connection. Repair as
necessar
y. If connections are okay, replace ABS ECU.

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Fig. 5: Testing Circuit Between ABS ECU & ABS Control (Motor) Relay
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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1999-2000 BRAKES Anti-Lock - RAV4
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