Page 1013 of 1897
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
Page 1015 of 1897
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 circuitOpen 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
Page 1017 of 1897
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
Page 1020 of 1897
- 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 rpmPark/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
Page 1022 of 1897
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
Page 1026 of 1897
A11665
IG Switch
BatteryECM Engine Room J/B
MAIN
Park/Neutral
Position SwitchAM2
W-B
Starter
B
58
3
2
110
4
1
B-W2C 2G2A
S1E8 ST Relay
E1 STA 7 1
ED
B-R B-R
II2
W-R
W-B
4
2D
42F 2A6
3
2B2
B-R 8
7
II1
B-W
FL
MainJ1
J/C
B-R
S212C7
7
B
IF1
1F74
W-R
B-R F6Fusible
Link
Block6 512
B
B
W-B DI-142
- DIAGNOSTICSENGINE
298 Author: Date:
2001 AVALON (RM808U)
Starter Signal Circuit
CIRCUIT DESCRIPTION
When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore
necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection
volume for the starting injection control and after-start injection control.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is not
cranked, proceed to the problem symptoms table on page DI-22.
DI08B-09
Page 1052 of 1897
I11736
Transponder Key
Amplifier
18
E7
E719
28
E7
CODERXCK TXCT
CODE RXCKTXCT
L-Y
L-O
P-G 4
3
2ECM
T6 DI-606
- DIAGNOSTICSENGINE IMMOBILISER SYSTEM
762 Author: Date:
2001 AVALON (RM808U)
DTC B2796/99 No Communication in Immobiliser system
CIRCUIT DESCRIPTION
This code is stored in memory when inserting the key that does not have a transponder chip or if communica-
tion between the key and ECM is impossible.
DTC No.DTC Detecting ConditionTrouble Area
B2796/99No communication
Key
Transponder Key Coil
Transponder Key Amplifier
Wire harness
ECM
WIRING DIAGRAM
DI1AT-23
Page 1055 of 1897
I11736
Transponder Key
Amplifier
18
E7
E719
28
E7CODERXCK TXCT
CODE RXCKTXCT
L-Y
L-O
P-G 4
3
2ECM
T6
- DIAGNOSTICSENGINE IMMOBILISER SYSTEM
DI-609
765 Author: Date:
2001 AVALON (RM808U)
DTC B2797/99 Communication Malfunction No.1
CIRCUIT DESCRIPTION
This code is detected when although the communication has been performed normally, an error occurs.
(Example. Some noise is included in communication line.)
DTC No.DTC Detecting ConditionTrouble Area
B2797/99Communication error
Wire Harness
Transponder Key Amplifier
ECM
WIRING DIAGRAM
DI6LC-01
