2001 TOYOTA AVALON diagram

A11663
VV1, VV2 and NE Signal Waveforms2 V
/Division
20 msec./Division (Idling)
VV1
NE VV2GND
GND
GND
DI-124
- DIAGNOSTICSENGINE
280 Author
: Date
:
2001 AVALON (RM808U)
DTC P1345 VVT Sensor/Camshaft Position Sensor Cir-
cuit Malfunction (Bank 1)
DTC P1350 VVT Sensor/Camshaft Position Sensor Cir-
cuit Malfunction (Bank 2)
CIRCUIT DESCRIPTION
VVT sensor (VV signal) consists of a magnet, iron core and pickup coil.
The VV signal plate has 3 teeth on its outer circumference and is installed the camshaft timing gear.
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 actual camshaft angle is detected by the VVT sensor and it provides feedback to the ECM to control
the intake valve timing in response to during condition.
DTC No.DTC Detecting ConditionTrouble Area
No VVT sensor (Camshaft position sensor) signal to ECM
during cranking at 4 sec. or more

Open or short in VVT sensor (camshaft position sensor) cir-
P1345
P1350No VVT sensor (Camshaft position sensor) signal to ECM with
5 sec. or more engine speed 600 rpm or morecuit

VVT sensor (camshaft position sensor)

Camshaft timing gearP1350
While crankshaft rotates twice, VVT sensor (Camshaft position
sensor) signal will be input to ECM 5 times.
Camshaft timing gear

ECM
WIRING DIAGRAM
Refer to DTC P0335 on page DI-67.
INSPECTION PROCEDURE
HINT:

If DTC P1345 is displayed, check left bank VVT sensor (camshaft position sensor).

If DTC P1350 is displayed, check right bank VVT sensor (camshaft position sensor).

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 VVT sensor (See page IG-7).
Reference: INSPECTION USING OSCILLOSCOPE
During idling, check the waveforms between terminals VV1 and
NE+, and VV2 and NE- of the ECM connector.
HINT:

The correct waveforms are as shown.

The waveform frequency is shortened as the engine
speed becomes higher.
NG Replace VVT sensor.
DI6T9-01

DI-126
- DIAGNOSTICSENGINE
282 Author
: Date
:
2001 AVALON (RM808U)
DTC P1346 VVT Sensor/Camshaft Position Sensor Cir-
cuit Range/Performance Problem (Bank 1)
DTC P1351 VVT Sensor/Camshaft Position Sensor Cir-
cuit Range/Performance Problem (Bank 2)
CIRCUIT DESCRIPTION
Refer to DTC P1345, P1350 on page DI-124.
DTC No.DTC Detection ConditionTrouble Area
P1346Deviation in crankshaft position sensor signal and VVT sensor
(bank 1) signal (2 trip detection logic)
Mechanical system malfunction (Jumping teeth of timing belt,
blt t thd)
P1351Deviation in crankshaft position sensor signal and VVT sensor
(bank 2) signal (2 trip detection logic)belt stretched)

ECM
WIRING DIAGRAM
Refer to DTC P1345, P1350 on page DI-124.
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 valve timing (Check for loose and jumping teeth of timing belt) (See page
EM-15).
NG Adjust valve timing (Repair or replace timing
belt).
OK
Check and replace ECM (See page IN-30).
DI6TA-01

A07621A09776
Right Bank OCV
1
2R-B
RECM
OC1+
OC1-
OC2+
OC2- 29
18 Left Bank OCV
R-WR-L 1
2E46
5
E4
E4
E4
- DIAGNOSTICSENGINE
DI-127
283 Author
: Date
:
2001 AVALON (RM808U)
DTC P1349 VVT System Malfunction (Bank 1)
DTC P1354 VVT System Malfunction (Bank 2)
CIRCUIT DESCRIPTION
VVT system controls the intake valve timing to proper timing in response to driving condition.
ECM controls Oil Control Valve (OCV) to make the intake valve timing properly, and, oil pressure controlled
with OCV is supplied to the VVT controller, and then, VVT controller changes relative position between the
camshaft and the crankshaft.
DTC No.DTC Detecting ConditionTrouble Area
P1349
P1354
Condition (a) or (b) continues for after the engine is warmed up
and engine speed at 400 - 4,000 rpm:
(a) Valve timing does not change from of current valve timing
(b) Current valve timing is fixed
Valve timing

OCV

VVT controller assembly

ECM
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTC P1349 is displayed, check left bank VVT system circuit.

If DTC P1354 is displayed, check right bank VVT system circuit.

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.
DI6TB-01

A11416
Fusible
Link
Block
FL
Main
BatteryStop Light
Switch
ALT
B
F10
F6STOP
R
211D 1B
1E
45
Light
Failure
Sensor 7
2
To Stop LightE8 15ECM
STP
E1 Driver Side J/B
3 11
W
1 1
16
4C 3C
3164F3F 3
5IK1 1D 1
1GG-W
G-WDriver Side J/B
J/B No.3
J/B No.4
G-W
G-W G-W G-W
DI-134
- DIAGNOSTICSENGINE
290 Author
: Date
:
2001 AVALON (RM808U)
DTC P1520 Stop Light Switch Signal Malfunction
CIRCUIT DESCRIPTION
This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut-off engine speed (The fuel cut-off engine speed is re-
duced slightly when the vehicle is braking.).
DTC No.DTC Detecting ConditionTrouble Area
P1520
Stop light switch does not turn off when repeating driving at 30
km or more 10 time or more after depressing brake (2 trip
detection logic)
Short in stop light switch signal circuit

Stop light switch

ECM
WIRING DIAGRAM
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 operation of stop light.
CHECK:
Check if the stop lights go on and off normally when the brake pedal is operated and released.
NG Check and repair stop light circuit.
DI088-09

A11417
Battery FL
Main B
F6 F71 12
81
B Fusible
Link BlockEngine Room J/B
2G 2B E8B-RECM
BATT EFI No.1
II1 10
B-R DI-136
- DIAGNOSTICSENGINE
292 Author
: Date
:
2001 AVALON (RM808U)
DTC P1600 ECM BATT Malfunction
CIRCUIT DESCRIPTION
Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is OFF for
use by the DTC memory and air-fuel ratio adaptive control value memory, etc.
DTC No.DTC Detecting ConditionTrouble Area
P1600Open in back up power source circuit
Open in back up power source circuit

ECM
HINT:
If DTC P1600 appear, the ECM does not store another DTC.
WIRING DIAGRAM
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.
DI089-09

DI-138
- DIAGNOSTICSENGINE
294 Author
: Date
:
2001 AVALON (RM808U)
DTC P1656 OCV Circuit Malfunction (bank 1)
DTC P1663 OCV Circuit Malfunction (bank 2)
CIRCUIT DESCRIPTION
Refer to DTC P1349, P1354 on page DI-127.
DTC No.DTC Detecting ConditionTrouble Area
P1656
P1663Open or short in oil control valve circuit

Open or short in OCV circuit

OCV

ECM
WIRING DIAGRAM
Refer to DTC P1349, P1354 on page DI-127.
INSPECTION PROCEDURE
HINT:

If DTC P1656 dysplayed, check left bank OCV circuit.

If DTC P1663 dysplayed, check right bank OCV circuit.

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 OCV circuit.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Connect the TOYOTA hand-held tester and select the VVT from the ACTIVE TEST menu.
CHECK:
Check the engine speed when operate the OCV by the TOYOTA hand-held tester.
OK:
VVT system is OFF (OCV is OFF): Normal engine speed
VVT system is ON (OCV is ON): Rough idle or engine stalled
OK Check for intermittent problems
(See page DI-3).
NG
DI6TC-01

- DIAGNOSTICSENGINE
DI-141
297 Author
: Date
:
2001 AVALON (RM808U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch go on when the shift lever is in the N or P shift position. When it goes on,
terminal NSW of the ECM is grounded to body ground via the starter relay, thus the terminal NSW voltage
becomes 0V. When the shift lever is in the D, 2, L or R position, the park/neutral position switch goes off,
so the voltage of ECM. Terminal NSW becomes battery voltage, the voltage of the ECM internal power
source. If the shift lever is moved from the N position to the D position, this signal is used for air-fuel ratio
correction and for idle speed control (estimated control), etc.
DTC No.DTC Detecting ConditionTrouble Area
P1780
When driving under conditions (a) and (b) for 30 sec. or more
the park/neutral position switch is ON (N position): (2 trip
dt ti l i)

Short in park/neutral position switch circuit
P k/ t l iti it hP1780detection logic)
(a) Vehicle speed: 40 km/h (25 mph) or more
(b) Engine speed: 1,500 - 4,000 rpm
Park/neutral position switch

ECM
HINT:
After confirming DTC P1780, use the TOYOTA hand-held tester to confirm the PNP switch signal from the
CURRENT DATA.
WIRING DIAGRAM
Refer to DTC P1780 on page DI-199.
INSPECTION PROCEDURE
Refer to DTC P1780 on page DI-199.
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.
DI08A-09

DI-54
- DIAGNOSTICSENGINE
210 Author
: Date
:
HINT:

When the DTC P0171 or P0174 is recorded, the actual air-fuel ratio is on the lean side. When DTC
P0172 or P0175 is recorded, the actual air-fuel ratio is on the rich side.

If the vehicle runs out of fuel, the air-fuel ratio is lean and DTC P0171 or P0174 is recorded. The MIL
then comes on.

If the total of the short-term fuel trim value and the long-term fuel trim value is within + 35 % (80°C
(176°F) or more), the system is functioning normally.

The A/F sensors (bank 1, 2 sensor 1) output voltage and the short-term fuel trim value can be read
using the OBD II scan tool or hand-held tester.

The ECM controls the voltage of AFR+, AFL+, AFR- and AFL- terminals of ECM to the fixed voltage.
Therefore, it is impossible to confirm the A/F sensor output voltage without OBD II scan tool or hand-
held tester.

OBD II scan tool (excluding hand-held tester) displays the one fifth of the A/F sensors (bank 1, 2 sen-
sor 1) output voltage which is displayed on the hand-held tester.
WIRING DIAGRAM
Refer to DTC P0125 on page DI-43.
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 air induction system (See page SF-1).
NG Repair or replace.
OK
2 Check injector injection (See page SF-23).
NG Replace injector.
OK