sensor TOYOTA CAMRY 2000 Service Repair Manual

INSPECTION PROCEDURE
HINT: If diagnostic trouble code ª22º (engine coolant temperature sensor circuit), ª24º (intake air
temperature sensor circuit), ª31º (manifold absolute pressure sensor circuit) and ª41 ª (throttle
position sensor circuit) are output simultaneously, E2 (sensor ground) may be open.
(1) Remove glove compartment.
(See page EG1±234).
(2) Disconnect the vacuum hose from the throt±
tle body, then apply vacuum to the throttle
opener (See page EG1±204).
(3) Turn ignition switch ON.
Measure voltage between terminals VTA, IDL and
E2 of engine control module connector when the
throttle valve is opened gradually from the closed
condition.
Check voltage between terminals VTA, IDL and E2 of engine
control module connector.
The voltage should increase steadily in propor±
tion to the throttle valve opening angle.
Check for momentary interruption
(See page EG1±309).
Throttle Valve
Fully Closed
Fully OpenVTA ± E2 Terminal
IDL ± E2
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(1) Disconnect throttle position sensor connector.
(2) Disconnect the vacuum hose from the throt±
tle body, then apply vacuum to the throttle
opener (See page EG1±204).
Check for open and short in harness and connector between engine
control module and throttle position sensor (See page IN±31).
Resistance between terminals 3 (VTA) and 1
(E2) should increase gradually in accordance
with the throttle valve opening angle.
Adjust or replace throttle position sensor
(See page EG1±209).
Check throttle position sensor.
Check and replace engine control module.Repair or replace harness or connector.
3 (VTA) ± 1 (E2) 2 (IDL) ± 1 (E2)
Throttle Valve
Fully Closed
Fully OpenTerminal
Measure resistance between terminals 3 (VTA), 2
(IDL) and 1 (E2) of throttle position sensor con±
nector when the throttle valve is opened gradu±
ally from the closed condition.
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CIRCUIT DESCRIPTION
The No.1 vehicle speed sensor outputs a 4±pulse signal for every revolution of the rotor shaft,
which is rotated by the transmission output shaft via the driven gear. After this signal is converted
into a more precise rectangular waveform by the waveform shaping circuit inside the combination
meter, it is then transmitted to the ECM. The ECM determines the vehicle speed based on the fre-
quency of these pulse signals.
For M /T
All conditions below are detected continuously
for 8 sec. or more.
(a) No.1 vehicle speed signal: 0 mph (km/h)
(b) Engine speed: Between 3,100 rpm and
5,000 rpm
(c) Engine coolant temp.: 80
C (176
F) or more
(d) Load driving
wWaveform between terminals SPD and E1 when vehicle
speed is approx. 12 mph (20 km/h).
HINT: The greater the vehicle speed, the greater the num±
ber of No.1 vehicle speed sensor signals produced.
For A/T
All conditions below are detected continuously
for 8 sec. or more.
(a) No.1 Vehicle speed signal: 0 mph (km/h)
(b) Engine speed: 3,100 rpm or more
(c) Park/Neutral position switch: OFF
HINT: In test mode, diagnostic trouble code 42 is output when vehicle speed is 3 mph (5 km/h)
or below.
wOpen or short in No.1 vehicle speed sensor
circuit.
wNo.1 vehicle speed sensor.
wCombination meter.
wECM Diagnostic Trouble Code Detecting Condition
Trouble Area
DTC 42 No.1 Vehicle Speed Sensor Signal Circuit
DTC No.
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(1) Remove glove compartment.
(See page EG1±234).
(2) Disconnect cruise control ECU connector.
(3) Shift the shift lever to N position or neutral.
(4) Jack up a front wheel on one side.
(5) Turn ignition switch on. Drive the vehicle and check if the operation of the speedometer in the combination meter is
normal.
The No. 1 vehicle speed sensor is operating normally if the speedometer display is normal.
Check voltage between terminal SPD of engine control module
connector and body ground.
Check speedometer circuit. See combination
meter troubleshooting on page BE±66.
Check speedometer circuit. See combination
meter troubleshooting on page BE±66.
Check operation of speedometer.
Check and replace engine control module.
INSPECTION PROCEDURE
Measure voltage between terminal SPD of
engine control module connector and body
ground when the wheel is turned slowly.
Voltage is generated intermittently.
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If the ECM detects the above diagnosis conditions, it operates the fail safe function in which the
corrective retard angle value is set to the maximum value.
DIAGNOSIS TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is
recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diag-
nostic trouble code is no longer detected.
Start engine and warm up.
After engine is warmed up, let it idle for 3 min.
With the A/C ON, perform quick racing (5,000 rpm) 3 times.
(Rapidly depress the accelerator pedal and suddenly release it.)
HINT: If a malfunction exists, the malfunction indicator lamp will light up when sudden
racing is performed.
NOTICE: If the conditions in this test are not strictly followed, detection of the mal-
function will not be possible.
CIRCUIT DESCRIPTION
Knock sensor is fitted the cylinder block to detect engine knocking. This sensor contains a piezoelec-
tric element which generates a voltage when it becomes deformed, which occurs when the cylinder
block vibrates due to knocking. If engine knocking occurs, ignition timing is retarded to suppress it.
w
Open or short in knock sensor circuit.
wKnock sensor (looseness)
wECM Open or short in knock sensor circuit with engine
speed between 1,200 rpm and 6,000 rpm.
Malfunction: Open or Short in Knock Sensor
Diagnostic Trouble Code Detecting Condition
Trouble Area
DTC 52 Knock Sensor Circuit
DTC No.
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Does malfunction disappear when a good knock
sensor is installed? Check for open and short in harness and
connector between knock sensor and ECM.Repair or replace harness or
connector. Check no continuity of knock sensor circuit.
DIAGNOSTIC CHART
WIRING DIAGRAM
Check and replace ECM.Replace knock sensor.Replace knock sensor. Check knock sensor.
YES
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Disconnect knock sensor connector.
Check for open and short in harness and connector between engine
control module and knock sensor (See page IN±31).
Does malfunction disappear when a good knock sensor is installed?
Check and replace engine control module.Replace knock sensor (See page EG1±93).
Replace knock sensor (See page EG1±93). Repair or replace harness or connector.
Check knock sensor.
YES
Measure resistance between the knock
sensor terminal and body.
Resistance: 1 M
or higher
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wSpread the time on the horizontal axis, and
confirm that period of the wave is 132
sec.
(Normal mode vibration frequency of knock
sensor: 7.6 KHz).
HINT: If normal mode vibration frequency is not 7.6
KHz, the sensor is malfunctioning.wWith the engine racing (4,000 rpm) measure
waveform between terminal KN K of engine
control module and body ground.
HINT: The correct waveform appears as shown in the
illustration on the left.
INSPECTION USING OSCILLOSCOPE Reference
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CIRCUIT DESCRIPTION
The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the
driving conditions, into the intake air mixture to slow down combustion, reduce the combustion
temperature and reduces NOx emissions. The amount of EGR is regulated by the EGR vacuum
modulator according to the engine load.
If even one of the following conditions is fulfilled,
the VSV is turned ON by a signal from the ECM.
This results in atmospheric air acting on the EGR
valve, closing the EGR valve and shutting off the
exhaust gas (EGR cut±OFF).
Under the following conditions, EGR is cut to
maintain driveability.
wEngine coolant temp. below 60
C (140
F).
wDuring deceleration (throttle valve closed).
wLight engine load (amount of intake air very
small).
wEngine speed over 4,400 rpm.
wEngine racing.
EG R gas temp. is 70
C (158
F) or below for 50
sec. under conditions (a) and (b).
(2 trip detection logic) *
(a) Engine coolant temp.: 80
C (176
F) or more.
(b) EGR operation possible (EX. A/T in 3rd speed
(5th for M/T), 55 ± 60 mph (88 ± 96 km/h),
Flat road).wOpen in EGR gas temp. sensor circuit.
wShort in VSV circuit for EGR.
wEGR hose disconnected, valve stuck.
wClogged EGR gas passage.
wECM Diagnostic Trouble Code Detecting Condition
*: See page
EG1±307.Trouble Area DTC No.
DTC 71 EGR System Malfunction
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Disconnect the EFI fuse (15 A) for 10 sec. or more, with IG switch OFF. Initiate
test mode (Connect terminals TE2 and E1 of data link connector, 1 or 2 with IG
switch OFF).
CIRCUIT DESCRIPTION (Cont'd)
DIAGNOSIS TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern.
(a) To simulate diagnostic trouble code detecting condition after diagnostic trouble code is
recorded.
(b) To check that the malfunction is corrected when the repair is completed confirming that diag-
nostic trouble code is no longer detected.
Malfunction: Open in EGR gas temp. sensor circuit
Start the engine and warm up.
After the engine is warmed up, let it idle for 3 min.
With the A/C ON and transmission in 5th gear A/T in ªDº position), drive at
55 ± 60 mph (88 ± 96 km/h) for 4 min. or less.
HINT: If a malfunction exists, the malfunction indicator lamp will light up dur-
ing step (4) .
NOTICE: If the conditions in this test are not strictly observed, detection of
the malfunction will not be possible.
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