TOYOTA CAMRY 1999 Service Repair Manual

A01991A01992A02359
G and NE Signal Waveforms
5 V/
Division
5 V/
Division G
NE
G
NE20 msec./Division (Idling)
10 msec./Division (Idling)
DI±60
± DIAGNOSTICSENGINE
1 Check resistance of crankshaft position sensor (See Pub. No. RM654U, page
IG±1).
Reference: INSPECTION USING OSCILLOSCOPE
During cranking or idling, check the waveform between termi-
nals G and G±, and NE and NE± of the ECM connector.
HINT:
The correct waveforms are as shown.
NG Replace crankshaft position sensor.
OK
2 Check for open and short in harness and connector between ECM and crank-
shaft position sensor (See page IN±29).
NG Repair or replace harness or connector.
OK
3 Inspect sensor installation (See Pub. No. RM654U, page IG±2) and teeth of crank-
shaft timing pulley (See Pub. No. RM654U, page EM±17).
NG Tighten sensor. Replace crankshaft timing
pulley.
OK
Check and replace ECM (See page IN±29).

± DIAGNOSTICSENGINE
DI±61
DTC P0340 Camshaft Position Sensor Circuit Malfunc-
tion
CIRCUIT DESCRIPTION
Camshaft position sensor (G signal) consists of magnet, iron core and pickup coil.
The G signal plate has one tooth on its outer circumference and is installed on the camshaft timing pulley.
When the camshafts rotate, the protrusion on the signal plate and the air gap on the pickup coil change,
causing fluctuations in the magnetic field and generating an electromotive force in the pickup coil.
The NE signal plate has 34 teeth and is installed on the crankshaft timing pulley. The NE signal sensor gener-
ates 34 signals at every engine revolution. The ECM detects the standard crankshaft angle based on the
G signal and the actual crankshaft angle and the engine speed by the NE signal.
DTC No.DTC Detecting ConditionTrouble Area
P0340
No camshaft position sensor signal to ECM during cranking
(2 trip detection logic)
Open or short in camshaft position sensor circuit

Camshaft position sensor
P0340No camshaft position sensor signal to ECM with engine speed
600 rpm or more

Camshaft osition sensor

Camshaft timing pulley

ECM
WIRING DIAGRAM
Refer to DTC P0335 on page DI±59.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected. When troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine was warmed up or not, the air±fuel ratio was lean
or rich, etc. at the time of the malfunction.
1 Check resistance of camshaft position sensor (See Pub. No. RM654U, page
IG±1).
Reference: INSPECTION USING OSCILLOSCOPE
Refer to DTC P0335 on page DI±59.
NG Replace camshaft position sensor.
OK
2 Check for open and short in harness and connector between ECM and camshaft
position sensor (See page IN±29).
NG Repair or replace harness or connector.
DI014±11

DI±62
± DIAGNOSTICSENGINE
OK
3 Inspect sensor installation (See Pub. No. RM654U, page IG±9) and tooth of cam-
shaft timing pulley (See Pub. No. RM654U, page EM±17).
NG Tighten sensor. Replace camshaft timing
pulley.
OK
Check and replace ECM (See page IN±29).

P25430
ECM
Throttle Body
EGR
Vacuum
Modulator EGR Valve
VSV
Exhaust Gas Throttle
Valve
u
± DIAGNOSTICSENGINE
DI±63
DTC P0400 Exhaust Gas Recirculation Flow Malfunction
CIRCUIT DESCRIPTION
The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the driving condi-
tions, into the intake air mixture to slow down combustion, reduce the combustion temperature and reduce
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 driveabil-
ity.

Before engine is warmed up.

During deceleration (throttle valve closed).

Light engine load (amount of intake air very small).

Engine idling.

Engine speed over 4,400 rpm.

High engine load (amount of intake air very large).
DTC No.DTC Detecting ConditionTrouble Area
P0400
After engine is warmed up, intake manifold absolute pressure
is larger than value calculated by ECM while EGR system is
ON (2 trip detection logic)

Vacuum or EGR hose is connected to wrong post

Open or short in VSV circuit for EGR

VSV for EGR

EGR system

EGR vacuum modulator

EGR valve

Manifold absolute pressure sensor

ECM
DI64W±01

A09397
ECM
J18
J/C
7 From
Battery
B
213
EFI Relay VSV
for EGR
21P-B23
E6EGR
E01
2K2
2J EFI
Engine Room J/B No.2 1B 9
B-Y
B
2AB-Y
IG3
EB
W-B
2F4B-Y
5
B-YFrom
Ignition SW
P20769
Vehicle Speed
60 ± 80 km/h
(38 ± 50 mph)
Idling
IG SW OFF
(1)(2)
Warm up
3 ± 5 min.2 min.
3 ± 5 min.Time (3)
(4)
(5)(6)
(7)
2 min. DI±64
± DIAGNOSTICSENGINE
WIRING DIAGRAM
SYSTEM CHECK DRIVING PATTERN
(1) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(2) Start and warm up the engine with all the accessories switched OFF.
(3) Run the vehicle at 60 ± 80 km/h (38 ± 50 mph) for 3 min. or more.
(4) Idle the engine for about 2 min.
(5) Do steps (3) and (4) again.
(6) Stop at safe place and turn the ignition switch OFF.
(7) Do steps (2) to (5) again.
(8) Check the READINESS TESTS mode on the OBD II scan tool or TOYOTA hand±held tester.
If COMPL is displayed and the MIL does not light up, the system is normal.
If INCMPL is displayed and the MIL does not light up, run the vehicle again and check it.
HINT:
INCMPL is displayed when either condition (a) or (b) exists.
(a) The system check is incomplete.

A00407
Air
Air FilterAir
E
System: OFFSystem: ON GG E
± DIAGNOSTICSENGINE
DI±65
(b) There is a malfunction in the system.
If there is a malfunction in the system, the MIL will light up after steps (2) to (5) above are done. (2 trip
detection logic)
INSPECTION PROCEDURE
HINT:

If DTCs P0105, P0106 and P0400 are output simultaneously, perform troubleshooting of DTC P0105
first.

Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame
records the engine conditions when the malfunction is detected. When troubleshooting it is useful for
determining whether the vehicle was running or stopped, the engine was warmed up or not, the air±fuel
ratio was lean or rich, etc. at the time of the malfunction.
TOYOTA hand±held tester:
1 Check connection of vacuum hose and EGR hose (See Pub. No. RM654U, page
EC±12).
NG Repair or replace.
OK
2 Check VSV for EGR.
PREPARATION:
(a) Connect the TOYOTA hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand±
held tester main switch ON.
(c) Select the ACTIVE TEST mode on the TOYOTA hand±
held tester.
CHECK:
Check the operation of the VSV when it is operated by the TOY-
OTA hand±held tester.
OK:
EGR system is OFF:
Air from port E is flowing out through the air filter.
EGR system is ON:
Air from port E is flowing out port G.
OK Go to step 4.
NG
3 Check operation of VSV for EGR (See Pub. No. RM654U, page SF±43).

DI±66
± DIAGNOSTICSENGINE
NG Replace VSV for EGR.
OK
Check for open and short in harness and con-
nector between engine room J/B No.2 and
ECM (See page IN±29).
4 Check EGR system (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
5 Check EGR vacuum modulator (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
6 Check EGR valve (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
7 Check manifold absolute pressure sensor (See Pub. No. RM654U, page SF±53).
NG Repair or replace.
OK

A09281
A09423
ON
E6 Connector
EGR
OFF
Air
FilterON
Air
E
G E
VSV is ON
VSV is OFF Air
G
± DIAGNOSTICSENGINE
DI±67
Check and replace ECM (See page IN±29).
OBD II scan tool (excluding TOYOTA hand±held tester):
1 Check connection of vacuum hose and EGR hose (See Pub. No. RM654U, page
EC±12).
NG Repair or replace.
OK
2 Check VSV for EGR.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Disconnect the E6 connector from the ECM.
(c) Turn the ignition switch ON.
CHECK:
Check the VSV function.
(1) Connect between terminal EGR of the ECM con-
nector and body ground (ON).
(2) Disconnect between terminal EGR of the ECM con-
nector and body ground (ON).
OK:
(1) VSV is ON:
Air from port E is flowing out through the air filter.
(2) VSV is OFF:
Air from port E is flowing out port G.
OK Go to step 4.
NG
3 Check operation of VSV for EGR (See Pub. No. RM654U, page SF±43).
NG Replace VSV for EGR.
OK

DI±68
± DIAGNOSTICSENGINE
Check for open and short in harness and con-
nector between engine room J/B No.2 and
ECM (See page IN±29).
4 Check EGR system (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
5 Check EGR vacuum modulator (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
6 Check EGR valve (See Pub. No. RM654U, page EC±12).
NG Repair or replace.
OK
7 Check manifold absolute pressure sensor (See Pub. No. RM654U, page SF±53).
NG Repair and replace.
OK
Check and replace ECM (See page IN±29).

A00414
Vehicle
Speed Sensor4±Pulse 4±Pulse
Combination Meter
ECM
Transaxle
Vehicle Speed Sensor
A09398
Combination Meter
14
V±WV±W
B J15
J/C
IF1
BV±W9
SPD5 V ECM
3
C11E4
± DIAGNOSTICSENGINE
DI±69
DTC P0500 Vehicle Speed Sensor Malfunction
CIRCUIT DESCRIPTION
The No.1 vehicle speed sensor outputs a 4±pulse signal for every revolution of the rotor shaft, which is ro-
tated 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 frequency of these pulse signals.
DTC No.DTC Detecting ConditionTrouble Area
P0500During vehicle is being driven, no vehicle speed sensor signal
to ECM (2 trip detection logic)

Combination meter

Open or short in vehicle speed sensor circuit

Vehicle speed sensor

ECM
WIRING DIAGRAM
DI01B±12