2000 TOYOTA CAMRY ignition

CIRCUIT DESCRIPTION
The signal from the A/T CPU retards the ignition timing of the engine during A/T shifting, thus
momentarily reducing torque output of the engine for smooth clutch operation inside the transmis-
sion and reduced shift shock.
If the ECM detects the diagnostic trouble code ª16º in memory, it prohibits the torque control of the
A/T which performs smooth gear shifting.
Are there any other codes (besides Code 16)
being output?Fault in communications between the engine
CPU and A/T CPU in the ECM
Go to relevant diagnostic trouble code
chart. Diagnostic Trouble Code Detecting Condition
DIAGNOSTIC CHART
Replace ECM.Trouble Area
DTC 16 A±T Control Signal Malfunction
DTC No.
wECM
YES
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±351

INSPECTION PROCEDURE
HINT: If diagnostic trouble codes 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) Turn ignition switch on.
Measure voltage between terminals THW and E2 of engine
control module connector.
Check voltage between terminals THW and E2 of engine control
module connector.
Check for momentary interruption
(See page EG1±309)
Engine Coolant Temp.
C (
F)
20 (68)
( Engine is cool )
80 (176)
(Engine is hot)0.2 ~1.0 v 0.5 ~ 3.4 V Voltage
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±358

(1) Remove glove compartment.
(See page EG1±234)
(2) Turn ignition switch on.
Measure voltage between terminals THA and E2
of engine control module connector.
Check voltage between terminals THA and E2 of engine control
module connector.
Check for momentary interruption
(See page EG1±309).
INSPECTION PROCEDURE
Intake air temp.
5C (5F)
0.5 ~ 3.4 V
0.2 ~ 1.0 V
60 (140)20 (68)Voltage
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±361

CIRCUIT DESCRIPTION
The main oxygen sensor is located in the exhaust manifold.
It indirectly determines whether the fuel mixture is rich or lean by detecting the concentration of
oxygen present in the exhaust gas.
Engine speed varies by more than 15 rpm over
the preceding crank position period during a period
of 50 sec. or more under conditions (a) and (b).
(2 trip detection logic) *
(a) Engine speed: Idling
(b) Engine coolant temp.: 60
C (140
F) or more (2) Engine speed varies by more than 15 rpm
over the preceding crank position period during
a period of 50 sec. or more under conditions
(a) and (b).
(2 trip detection logic) *
(a) Engine speed: Idling
(b) Engine coolant temp.: 60
C (140
F) or more.wOpen or short in injector circuit
wFuel line pressure (injector leak, blockage)
wMechanical system malfunction
(skipping teeth of timing belt)
wIgnition system
wCompression pressure
(foreign object caught in valve)
wAir leakage
wECM
wOpen or short in injector circuit
wFuel line pressure (injector leak, blockage)
wMechanical system malfunction
(skipping teeth of timing belt)
wIgnition system
wCompression pressure
(foreign object caught in valve)
wAir leakage
wECM (1) Main oxygen sensor voltage is 0.45 V or
less (lean) for 90 sec. under conditions (a)
and (b).
(2 trip detection logic) *
(a) Engine coolant temp.: 60
C (140
F) or more.
(b) Engine speed: 1,500 rpm or more.wOpen or short in main oxygen sensor circuit
wMain oxygen sensor
wIgnition system
w ECM Diagnostic Trouble Code Detecting Condition
*: See page EG1±307Trouble Area
DTC 25 26 Air±Fuel Ratio Lean Rich Malfunction
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±363

CIRCUIT DESCRIPTION
By a built±in sensor unit, the manifold absolute
pressure sensor detects the intake manifold absolute
pressure as a voltage.
The ECM then determines the basic injection dura±
tion and basic ignition advance angle based on this
voltage.
Since the manifold absolute pressure sensor does
not use the atmospheric pressure as a criterion, but
senses the absolute pressure inside the intake man±
ifold (the pressure in proportion to the preset abso±
lute vacuum O), it is not influenced by fluctuations
in the atmospheric, pressure due to high altitude
and other factors. This permits it to control the air±
fuel ratio at the proper level under all conditions.
If the ECM detect diagnostic trouble code ª31 ª, it operates the fail safe function, keeping the ignition
timing and fuel injection volume constant and making it possible to drive the vehicle.w
Open or short in manifold absolute pressure
sensor circuit.
wManifold absolute pressure sensor.
wECM Open or short in manifold absolute pressure sensor
circuit for 0.5 sec. or more.Diagnostic Trouble Code Detecting Condition Trouble Area
DTC 31 Manifold Absolute Pressure Sensor Circuit
DTC No.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±372

(1) Remove glove compartment.
(See page EG1±234).
(2) Turn ignition switch on.
Measure voltage between terminals VC and E2 of
engine control module connector.
Voltage: 4.5 ~ 5.5 V Check voltage between terminals VC and E2 of engine control
module connector.
Check and replace engine control module.
INSPECTION PROCEDURE
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±374

Check for open and short in harness and connector between engine
control module and manifold absolute pressure sensor
(See page IN±31).
Turn ignition switch on
Check voltage between terminals PIM and E2 of engine control
module connector.
Check and replace manifold absolute pressure
sensor.When diagnostic trouble code 31 is dis-
played, check and replace engine control
module.
Repair or replace harness or connector. Voltage: 13 ± 3.9 V Measure voltage between terminals PI M
and E2 of engine control module connector.
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±375

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
± 5S±FE ENGINECIRCUIT INSPECTIONEG1±378