1999 TOYOTA CAMRY Fuel line input to engine

P24296
Throttle Position
Sensor
VC
VTA
E2ECM
± DIAGNOSTICSENGINE (5S±FE)
DI±49
284 Author: Date:
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle. When the throttle valve
is fully closed, a voltage of approximately 0.3 ~ 0.8 V is applied
to terminal VTA of the ECM. The voltage applied to the termi-
nals VTA of the ECM increases in proportion to the opening
angle of the throttle valve and becomes approximately 3.2 ~ 4.9
V when the throttle valve is fully opened. The ECM judges the
vehicle driving conditions from this signal input from terminal
VTA, and uses it as one of the conditions for deciding the air±
fuel ratio correction, power increase correction and fuel±cut
control etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) continues with more than 5 sec.:
(a) VTA < 0.1 V
(b) VTA > 4.9 V
Open or short in throttle position sensor circuit

Throttle position sensor

ECM
HINT:
After confirming DTC P0120, use the OBD II scan tool or TOYOTA hand±held tester to confirm the throttle
valve opening percentage.
Throttle valve opening position
expressed as percentage
Trouble Area
Throttle valve fully closedThrottle valve fully open
Trouble Area
0 %0 %VC line open
VTA line open or short
Approx. 100 %Approx. 100 %E2 line open
DI00R±05

P24296
ECM
Throttle Position
Sensor
VC
VTA1
E2
S05019
ECM
1
3
25 V
VC
VTA1
E2 Y
L
BR Throttle Position Sensor
E102
23
18 E10
E10
± DIAGNOSTICSENGINE (1MZ±FE)
DI±239
474 Author: Date:
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle. When the throttle valve
is fully closed, a voltage of approximately 0.7 V is applied to ter-
minal VTA of the ECM. The voltage applied to the terminals VTA
of the ECM increases in proportion to the opening angle of the
throttle valve and becomes approximately 2.7 ~ 5.2 V when the
throttle valve is fully opened. the ECM judges the vehicle driving
conditions from these signals input from terminals VTA and
uses them as one of the conditions for deciding the air±fuel ratio
correction, power increase correction and fuel±cut control etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) continues:
(a) VTA
0.1 V
(b) VTA
4.9 V

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
HINT:
After confirming DTC P0120, use the OBD II scan tool or TOYOTA hand±held tester to confirm the throttle
valve opening percentage and closed throttle position switch condition.
Throttle valve opening position
expressed as percentage
Trouble Area
Throttle valve fully closedThrottle valve fully open
Trouble Area
0 %0 %VC line open
VTA line open or short
Approx. 100 %Approx. 100 %E2 line open
WIRING DIAGRAM
DI07K±06

This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline
of the engine control is explained here.
1. INPUT SIGNALS
(1) Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built±in thermistor with a resistance which
varies according to the engine coolant temp. thus the engine coolant temp. is input in the form of a control signal into
TERMINAL THW of the engine control module.
(2) Intake air temp. signal circuit
The intake air temp. sensor detects the intake air temp. , which is input as a control signal into TERMINAL THA of the
engine control module.
(3) Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINAL OX2 of the engine
control module.
(4) RPM signal circuit
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor.
Camshaft position is input as a control signal to TERMINAL G of the engine control module, and engine RPM is input
into TERMINAL NE.
(5) Throttle signal circuit
The throttle position sensor detects the throttle valve opening angle, which is input as a control signal into TERMINAL
VTA of the engine control module.
(6) Vehicle speed signal circuit
The vehicle speed sensor, installed inside the transmission, detects the vehicle speed and inputs a control signal into
TERMINAL SPD of the engine control module.
(7) Park/Neutral position SW signal circuit
The Park/Neutral position SW detects whether the shift position are in neutral, parking or not, and inputs a control signal
into TERMINAL STA of the engine control module.
(8) A/C SW signal circuit
The A/C amplifier is built in the engine control module. The signal from the A/C SW is input into TERMINAL A/CS of the
engine control module.
(9) Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, the
voltage for engine control module start±up power supply is applied to TERMINAL +B of engine control module via EFI
relay.
(10) Intake air volume signal circuit
Intake air volume is detected by the manifold absolute pressure sensor (for manifold pressure) and is input as a control
signal into TERMINAL PIM of the engine control module.
(11) Starter signal circuit
To confirm whether the engine is cranking, the voltage applied to the starter motor during cranking is detected and the
signal is input into TERMINAL NSW of the engine control module as a control signal.
(12) Electrical load signal circuit
The signal when systems such as the rear window defogger, headlights, etc. Which cause a high electrical burden are
on is input to TERMINAL ELS as a control signal.
(13) Air fuel ratio signal circuit
The air fuel ratio is detected and input as a control signal into TERMINAL AF+ of the engine control module.
SYSTEM OUTLINE

This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline
of the engine control is explained here.
1. INPUT SIGNALS
(1) Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built±in thermistor with a resistance which
varies according to the water temp. is input into TERMINAL THW of the engine control module as a control signal.
(2) Intake air temp. signal circuit
The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temp., which is input as a
control signal into TERMINAL THA of the engine control module.
(3) Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINALS OXL1, OXR1
(Except California) and OXS of the engine control module. To maintain stable detection performance by the heated
oxygen sensor, a heater is used for warming the sensor. The heater is also controlled by the engine control module
(HTL, HTR (Except California) and HTS).
(4) RPM signal circuit
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor.
The camshaft position is input as a control signal to TERMINAL G22+ of the engine control module, and the engine
RPM is input into TERMINAL NE+.
(5) Throttle signal circuit
The throttle position sensor detects the throttle valve opening angle as a control signal, which is input into TERMINAL
VTA1 of the engine control module.
(6) Vehicle speed signal circuit
The vehicle speed sensor, installed inside the transmission, detects the vehicle speed and inputs a control signal into
TERMINAL SPD of the engine control module.
(7) Park/Neutral position SW signal circuit
The Park/Neutral position SW detects whether the shift position is in neutral, parking or not, and inputs a control signal
into TERMINAL STA of the engine control module.
(8) A/C SW signal circuit
The A/C control assembly (Automatic A/C) or A/C Amplifier (Manual A/C) inputs the A/C operations into TERMINAL A/C
of the engine control module as a control signal.
(9) Battery signal circuit
(California or w/ engine immobiliser and/or traction control)
Voltage is always supplies to TERMINAL BATT of the engine control module.
If you turn on the ignition SW, the current goes from TERMINAL MREL of the engine control module to the EFI relay and
put on the relay, and the voltage related to the engine control module operation is supplied to TERMINAL +B of the
engine control module through the EFI relay.
(Except California or w/ engine immobiliser and/or traction control)
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on,
voltage for engine control module start±up power supply is applied to TERMINAL +B of engine control module via EFI
relay.
(10) Intake air volume signal circuit
Intake air volume is detected by the mass air flow meter and a signal is input into TERMINAL VG of the engine control
module as a control signal.
(11) NSW signal circuit
To confirm whether the engine is cranking, the voltage applied to the starter motor during cranking is detected and the
signal is input into TERMINAL NSW of the engine control module as a control signal.
(12) Engine knock signal circuit
Engine knocking is detected by the knock sensor 1 and 2, then the signals are input into TERMINALS KNKR and KNKL
of the engine control module as a control signal.
(13) Air fuel ratio signal circuit (California)
The air fuel ratio is detected and input as a control signal into TERMINALS AFL+, AFR+ of the engine control module.
SYSTEM OUTLINE

ENGINE CONTROL (5S±FE)
This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline
of the engine control is explained here.
1. INPUT SIGNALS
(1) Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built±in thermistor with a resistance which
varies according to the engine coolant temp. thus the engine coolant temp. is input in the form of a control signal into
TERMINAL THW of the engine control module.
(2) Intake air temp. signal circuit
The intake air temp. sensor detects the intake air temp., which is input as a control signal into TERMINAL THA of the
engine control module.
(3) Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINAL OX1 (except
California) and OX2 of the engine control module.
(4) RPM signal circuit
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor.
Camshaft position is input as a control signal to TERMINAL G+ of the engine control module, and engine RPM is input
into TERMINAL NE+.
(5) Throttle signal circuit
The throttle position sensor detects the throttle valve opening angle, which is input as a control signal into TERMINAL
VTA of the engine control module.
(6) Vehicle speed signal circuit
The vehicle speed sensor, installed inside the transmission, detects the vehicle speed and inputs a control signal into
TERMINAL SPD of the engine control module.
(7) Park/Neutral position SW signal circuit (A/T)
The Park/Neutral position SW detects whether the shift position are in neutral, parking or not, and inputs a control signal
into TERMINAL STA of the engine control module.
(8) A/C SW signal circuit
The A/C amplifier function is built in the engine control module. The A/C SW signal inputs into the TERMINAL A/C SW of
the engine control module.
(9) Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, the
voltage for engine control module start±up power supply is applied to TERMINAL +B of engine control module via EFI
relay.
(10) Intake air volume signal circuit
Intake air volume is detected by the manifold absolute pressure sensor (for manifold pressure) and is input as a control
signal into TERMINAL PIN of the engine control module.
(11) Starter signal circuit
To confirm whether the engine is cranking, the voltage applied to the starter motor during cranking is detected and the
signal is input into TERMINAL NSW of the engine control module as a control signal.
(12) Engine knock signal circuit
Engine knocking is detected by knock sensor 1 and the signal is input into TERMINAL KNK as a control signal.
(13) Electrical load signal circuit
The signal when systems such as the rear window defogger, headlights, etc. Which cause a high electrical burden are
on is input to TERMINAL ELS as a control signal.
(14) Air fuel ratio signal circuit (California)
The air fuel ratio is detected and input as a control signal into TERMINAL AF+ of the engine control module.
SYSTEM OUTLINE

ABS AND TRACTION CONTROL
(ABS)
ABS is a brake system designed for the purpose to improve the operating ability securing the stability of the vehicle by
preventing the looking±up of the vehicle controlling the wheel cylinder pressure of all the four wheels at the time of sudden
braking.
1. INPUT SIGNALS
(1) Speed sensor signal
The speed of the wheels is detected and input to TERMINALS FL+, FR+, RL+, and RR+ of the ABS and traction ECU.
(2) Stop light SW signal
A signal is input to TERMINAL STP of the ABS and traction ECU when brake pedal is depressed.
2. SYSTEM OPERATION
When the wheels are to be locked±up, the solenoid inside the actuator will be controlled by the signal from the ABS and
traction ECU and the brake fluid in the wheel cylinder will flow through the reservoir and reduce the hydraulic pressure.
While the ABS is in operation, as the ABS and traction ECU always outputs the operation signal to the pump inside the
actuator, brake fluid stored inside the reservoir will be suctioned up by the pump inside the actuator and returned to the
master cylinder.
When the hydraulic pressure of the wheel cylinder is decompressed or increased until the necessary hydraulic pressure, the
solenoid inside the actuator is controlled by the control signal from the ABS and traction ECU and as a result, hydraulic
pressure of the wheel cylinder will be closed at both routes of the master cylinder and reservoir sides and the hydraulic
pressure of the wheel cylinder will become to be in the holding condition.
If the increase of hydraulic pressure volume of the wheel cylinder becomes necessary, with the control signal from the ABS
and traction ECU, the solenoid inside the actuator will be controlled and become the same condition as usual and the brake
fluid of the master cylinder will be sent to the wheel cylinder and will increase the hydraulic pressure of the wheel cylinder. At
this time, in the case that the brake fluid stays left in the reservoir, it will be sucked up by the pump inside the actuator and
will be sent to the wheel cylinder.
Also, increasing speed of the hydraulic pressure is controlled by outputting the increasing and the said holding one after
another.
(Traction control)
Traction control system is designed to perform the engine output control by the fuel cut and hydraulic pressure control of
driving wheel brake and control the spinning of the driving wheels. By doing this, it improves starting acceleration and
operating ability of the vehicle securing the driving ability in accordance with the road surface condition.
3. TRACTION CONTROL OPERATION
Estimating the vehicle speed from the rear wheel speed, comparing it with the front, driving wheel speed and judging the grip
condition of the driving wheels. From the estimated vehicle speed, target speed of the driving speed will be set. When the
front, driving wheel speed exceeds the control starting speed, it judges that the tire slip is occurred and performs the fuel cut
cylinder number control and brake control and then adjust to make the front wheel speed become the traction control target
speed. Controlling of the traction control will be completed when the vehicle move onto the road where the driving wheels will
not have a tire slip or when the driver decelerate.
ABS MOTOR RELAY [R/B NO.3]
3±4 : Approx. 62 W
ABS SOL RELAY [R/B NO.3]
4±6 : Approx. 80 W
A9, A10 ABS SPEED SENSOR FRONT LH, RH
1±2 :0.6 kW±2.5 kW
A15 (A), A16 (B), A17 (C) ABS AND TRACTION ECU
(B) 8±GROUND : Approx. 12 volts with the ignition SW at ON position
(B)11±GROUND : Continuity with the ignition SW on and the traction off SW on (Traction control off)
(B)16±GROUND : Approx. 12 volts with the brake pedal depressed
(A)15, (C) 9, (C) 10±GROUND : Always continuity
A25, A26
ABS SPEED SENSOR REAR LH, RH
1±2 :1.2 kW±2.3 kW
T2 THROTTLE POSITION SENSOR
1±2 :3.5 kW±5.0 kW
SYSTEM OUTLINE
SERVICE HINTS