2000 TOYOTA CAMRY Actuator

DIAGNOSIS SYSTEM
DESCRIPTION
The ECM contains a built±in self±diagnosis system by which
troubles with the engine signal network are detected and a
Malfunction indicator lamp on the instrument panel lights up.
By analyzing various signals as shown in the later table (See
page EG1±300) the Engine Control Module (ECM) detects
system malfunctions relating to the sensors or actuators.
In the normal mode, the self±diagnosis system monitors 14
items, indicated by code No. as shown in EG1±300. A mal-
function indicator lamp informs the driver that a malfunction
has been detected. The light goes off automatically when the
malfunction has been repaired. But the diagnostic trouble
code(s) remains stored in the ECM memory (except for code
Nos. 16). The ECM stores the code(s) until it is cleared by
removing the EFI fuse with the ignition switch off.
The diagnostic trouble code can be read by the number of
blinks of the malfunction indicator lamp when TE1 and E1
terminals on the data link connector 1 or 2 are connected.
When 2 or more codes are indicated, the lowest number
(code) will appear first.
In the test mode, 9 items, indicated by code No. as shown in
EG1±300 are monitored. If a malfunction is detected in any
one of the systems indicated by code Nos. 13, 22, 24, 25, 26,
27, 31, 41 and 71 the ECM lights the malfunction indicator
lamp to warn the technician that malfunction has been de-
tected. In this case, TE2 and E1 terminals on the data link
connector 1 or 2 should be connected as shown later. (See
page EG1±298).
In the test mode, even if the malfunction is corrected, the
malfunction code is stored in the ECM memory even when
the ignition switch is off (except code Nos. 43 and 51). This
also applies in the normal mode. The diagnostic mode (nor-
mal or test) and the output of the malfunction indicator lamp
can be selected by connecting the TE1, TE2 and E1 termi-
nals on the data link connector 1 or 2, as shown later.
A test mode function has been added to the functions of the
self±diagnostic system of the normal mode for the purpose of
detecting malfunctions such as poor contact, which are diffi-
cult to detect in the normal mode. This function fills up the
self±diagnosis system. The test mode can be implemented
by the technician following the appropriate procedures of
check terminal connection and operation described later.
(See page
EG1±298)
± 5S±FE ENGINEDIAGNOSIS SYSTEMEG1±296

60CHASSISÐBRAKES
BRAKES
 DESCRIPTION
The ventilated disc brake is used for front brake on all models.
The rear drum brake is used on the 5S±FE engine model, and the rear solid disc brake is used on the 1MZ±FE engine
model.
The ABS is provided on the 5S±FE engine CE grade model as an option and on other models as standard.
An ABS actuator has been changed to the 2±position solenoid valve type actuator.
A compact and lightweight ABS & TRAC system, in which the ABS and TRAC functions are integrated, is made
available as an option on the LE and XLE grade models with the 1MZ±FE engine.
A portless and portless type master cylinder is used on the models with ABS & TRAC system.
The center lever type parking brake is adopted on all models.

62CHASSISÐBRAKES
 MASTER CYLINDER
As in the previous model, the lockheed and
lockheed type master cylinder is used on the models
without ABS, and the portless and lockheed type
master cylinder is used on the models with ABS.
The portless and portless type master cylinder is
used on the models with ABS & TRAC system.
 ABS
1. General
As in the previous model, the braking of each wheel is controlled by the following 3 modes: pressure reduction,
pressure holding, and pressure holding mode.
During ABS activation, the ECU controls the fluid pressure of each front left and right wheels independently while
the fluid pressure of rear left and right wheels is controlled simultaneously.
However, the ABS actuator has been changed as shown in the table below. In addition, the diagnostic codes have
alsom been changed.
For diagnostic code check method, diagnostic code and diagnostic code clearance, see the 1997 Camry Repair
Manual (Pub. No. RM503U).
The operation of the ABS is the same as that of the '96 Corolla.

Type of ABS Actuator
Model
NewPreviousTypeNewPrevious
NIPPONDENSO ABS
(TMC Produced Model) 2±Position Solenoid Valve Type
Actuator
The ECU and realy are separate.3±Position Solenoid Valve Type
Actuato
The ECU and relay are separate.
BOSCH ABS
(TMM Produced Model)2±Position Solenoid Valve Type
Actuator with ECU and Relay3±Position Solenoid Valve and
Mechanical Valve Type Actuator
with ECU and Relay

72CHASSISÐBRAKES
5. Function of Components
No.ComponentFunction
1Slip Indicator LightBlinks to inform the driver when the TRAC system is operated.
2TRAC OFF Indicator Light
Lights to inform the driver when the TRAC system is turned OFF by
the by the TRAC OFF switch. And, blinks to alert the driver when
the ECU detects the malfunction in the TRAC system.
3ECM
Sends signals to the ABS & TRAC ECU, such as the throttle
valve opening angle, specific volume of intake air signal, etc.
Controls the engine output and shift timing in accordance with
the fuel cutoff request and shift timing request that are output by
the ABS & TRAC ECU.
4ABS & TRAC ECU
Judges the vehicle driving condition based on signals from 4 speed
sensors and signals from ECM, and sends fuel cut and shift timing
demand signals to the ECM and brake control signal to the ABS &
TRAC actuator.
5ABS & TRAC Actuator
Controls the brake fluid pressure to each brake wheel cylinder
of the driving wheel (front wheel) by signals from the ABS &
TRAC ECU.
ABS & TRAC
Solenoid RelayDirects electricity to the solenoid valves in the actuator.
6ABS & TRAC
RelayPump Motor
RelayControls the pump motor operation in the actuator.
7Speed Sensors (Front and Rear)Detect the wheel speed of each of four wheels.
8Throttle Position SensorDetects the throttle valve opening angle.
9TRAC OFF SwitchTurns the TRAC system inoperative.

73 CHASSISÐBRAKES
6. Construction and Operation of Components
TRAC OFF Switch and Indicator Light
1) TRAC OFF Switch
When pressing, this switch turns the TRAC system to be inoperative. Pressing it again changes it to be operative.
When turning the ignition switch from ªOFFº to ªONº, TRAC system always becomes operative.
2) TRAC OFF Indicator Light
This light comes on when the TRAC system is set inoperative by the TRAC OFF switch, and informs the driver
accordingly. And blinks to alert the driver when a malfunction has occurred in the engine and TRAC system.
3) Slip Indicator Light
When the TRAC system is operative, the light blinks and informs the driver accordingly.
ABS & TRAC Actuator
1) Construction
The ABS & TRAC actuator consists of 12 two±position solenoid valves, 1 motor, 2 pumps 2 reservoirs and 2 pressure
regulator valves.
The 12 two±position solenoid valves consists of 2 master cut solenoid valves, 2 reservoirs cut solenoid valves, 4
pressure holding valves, and 4pressure reduction valves.
Pressure regulator valve is assembled into the master cut solenoid valve.
The basic construction and operation of the pump, reservoir, pressure holding valve, and pressure reduction valve
are shared with ABS.
a. Master Cut Solenoid Valve
When the TRAC system is active, a signal from the ABS & TRAC ECU causes the master cut solenoid valve to turn
ON in order to shut off the circuit between the master cylinder and the front brake wheel cylinder.

76CHASSISÐBRAKES
b. During Vehicle Acceleration (TRAC System Activated)
When a front wheel slips during acceleration, the TRAC system controls the engine output and braking of the front
wheels to help preventing wheel slippage.
The brake fluid pressure applied to the right and left front wheels is controlled separately accordingly to 3 control
modes ( pressure increase, holding, and pressure reduction) as explained below.
i) Pressure Increase Mode
During sudden acceleration or driving on a slippery surface, if the front wheels start to slip, a control signal from the
ABS & TRAC ECU causes the ABS & TRAC actuator to control the valves and pumps as described below, to effect
the pressure increase mode.
When the master cut and reservoir cut solenoid valves turn ON, port B is closed, port H is open and the pump operates
at the same time.
Accordingly, the brake fluid will be suctioned up from the master cylinder through parts G and H.
Then the brake fluid that is pressurized by the pump will be applied to the wheel cylinder through C and D.
Also, the brake fluid that pressurized by the pump is regulated to a constant pressure by the pressure regulator valve.

Hydraulic Circuit

Condition of Each Valve and Pump Motor
Part Name
Signal from
ABS & TRAC ECUOperation
Master Cut Solenoid ValveONPort BClosed
Reservoir Cut Solenoid ValveONPort HOpen
Pressure Holding ValveOFFPort COpen

81CHASSISÐBRAKES
2) Initial Check
An initial check is carried out once every a few seconds after the ignition was turned on. The functions of each
solenoid valve and pump motor in the actuator are checked on order.
3) Self±Diagnosis
If the ABS & TRAC ECU detects a malfunction in the engine, ABS or TRAC system, it blinks the TRAC OFF
indicator light to alert the driver of the malfunction. At the same, the ABS & TRAC 1997 Avalon Repair Manual
(Pub. No. RM504U) for the diagnostic code check method, diagnostic code and diagnostic code clearance.
4) Fail±Safe
In the event of a malfunction in the engine, ABS or TRAC system, the ABS & ECU prohibits the TRAC system.
Thus, the brake and engine controls will operate in the same conditions as those without the TRAC system.

116BODY ELECTRICALÐACCESSORIES
 CRUISE CONTROL SYSTEM
1. General
Once the system is set to a desired vehicle speed, the engine throttle position is adjusted automatically to maintain
the vehicle speed at that speed without depressing the accelerator pedal.
The basic sonstruction and operation of this system are the same as the previous model. However, on the new model,
the control method for the manual and auto cancel functions have been changed. Also, a new motor type actuator
that is both lightweight and simple in construction has been adopted.
2. Construction and Operation
Actuator
The new Camry has adopted a new motor type actuator. The new motor type actuator consists of a motor, control link
and limit swit h, etc. as shown belwo.
The potentiometer hat measured the opening angle of the control link and transmitted the signals to the cruise control
ECU has been discontinued in the new actuator. The new actuator is equipped it with a compact motor. As a result,
the new actuator is made both lightweight and simple in construction.
Without the potentiometer, the new actuator contnuously regulates the opening angle of the control link.
This is made possible by the ECU, which compares the curent vehiclespeed input with the desired vehicle speed that
is stored in memory, and the result of that comparison is transmitted to the actuator.
Cruise Control ECU
1) Manual Cancel Fucntion
The manual cancel function has been changed as follows:
New
Previous
Transaxle shifted to positions other than ªDº.Transaxle shifted to ªNº position.
ÐPull up the parking brake lever.