Page 457 of 4770
Check for open in harness and connector between IG switch and
EFI main relay, EFI main relay and body ground (See page IN±31).
Remove EFI fuse from J/B No.2.
Check continuity of EFI fuse.
Continuity
Check for open in harness and connector
between EFI main relay and battery, EFI main
relay and engine control module.Check for short in all the harness and
components connected to EFI fuse (See
attached wiring diagram). Remove under cover and finish panel.
Check continuity between terminals.
Repair or replace harness or connector.
Check ignition switch.
Replace ignition switch.
Check EFI fuse.
Switch positioncontinuity
10
AM2 Terminal
4
AM1 3
ACC6
ST27
ST19
IG2
START2
lG1
LOCK
ACC
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±407
Page 469 of 4770
CIRCUIT DESCRIPTION
Fuel pump control
The fuel pump is switched on (low voltage at terminal FC) when STA is on or while the NE signal
is input to the ECM.
In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition
switch to the starter relay coil, the starter relay switches on and current flows to coil L1 of the circuit
opening relay. Thus the circuit opening relay switches on, power is supplied to the fuel pump and the
fuel pump operates.
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil L2
of the circuit opening relay, the relay switches on and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON)
and the fuel pump also keeps operating.
Fuel System Circuit
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±419
Page 470 of 4770
Check for open in harness and connector
between circuit opening relay and fuel pump
and body ground. Check for open in harness and connector
between EFI main relay and circuit opening
relay and ECM.Repair or replace harness or connector. Check for ECM power source circuit.
DIAGNOSTIC CHART
Check for circuit opening relay.
Replace circuit opening relay. Check voltage terminal FC. Check and replace ECM.
Replace fuel pump. Check fuel pump.Repair or replace.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±420
Page 473 of 4770
Check for open in harness and connector between EFI main relay and
circuit opening relay, circuit opening relay and engine control module
(See page IN±31).
(1) Remove glove compartment
(See page EG1±217).
(2) Remove circuit opening relay from R/B No.6.
Check continuity between terminals of circuit
opening relay shown below.
Check for open in harness and connector between circuit opening relay and fuel pump, fuel
pump and body ground.(1) Apply battery voltage between terminals 3
and 6.
(2) Check continuity between terminals 1 and 2.
Check fuel pump (See page EG1±177). Check circuit opening relay.
Repair or replace harness or connector. Replace circuit opening relay.
Replace fuel pump.
Terminals 1 and 2Terminals 1 and 2
Terminals 3 and 6Terminals 2 and 4
ContinuityContinuity
ContinuityOpen
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±423
Page 474 of 4770
CIRCUIT DESCRIPTION
VSV Circuit for Fuel Pressure Control (Only for California
spec.)
Check for open and short in harness and
connector between EFI main relay and ECM.Proceed to next circuit inspection
shown on matrix chart
(See page EG1±327).
Repair or replace harness or connector. Check voltage of VSV power source. Check VSV for fuel pressure control.
Check and replace ECM.Replace VSV.
DIAGNOSTIC CHART
The ECM turns on a VSV (Vacuum Switching
Valve) to draw the air into the diaphragm chamber
of the pressure regulator if it detects that the tem-
perature of the engine coolant is too high during
engine starting. The air drawn into the chamber
increases the fuel pressure to prevent fuel vapor
lock at high engine temperature in order to help the
engine start when it is warm.
Fuel pressure control ends approx. 90 secs. after
the engine is started.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±424
Page 477 of 4770
(1) Remove glove compartment
(See page EG1±234).
(2) Turn ignition switch ON.
Measure voltage between terminal FPU of engine
control module connector and body ground.
Check for open and short in harness and connector between engine
control module and VSV, VSV and EFI main relay (See page IN±31). Check voltage between terminal FPU of engine control module
connector and body ground.
Proceed to next circuit inspection shown
on matrix chart (See page EG1±327).
Check and replace engine control module.Repair or replace harness or connector. Voltage: 9 ±14 V
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±427
Page 541 of 4770

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
Page 551 of 4770

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.