Page 20 of 1897

AC2810
AC0Y9-02
AC2811
N11084
Wrong Okay
HI LO HILO
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-1
1923 Author: Date:
2001 AVALON (RM808U)
AIR CONDITIONING SYSTEM
PRECAUTION
1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED
AREA OR WEAR EYE PROTECTION
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN
YOUR EYES OR ON YOUR SKIN
If liquid refrigerant gets in your eyes or on your skin.
(a) Wash the area with lots of cool water.
CAUTION:
Do not rub your eyes or skin.
(b) Apply clean petroleum jelly to the skin.
(c) Go immediately to a physician or hospital for professional
treatment.
4. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED
FLAME
5. BE CAREFUL NOT TO DROP CONTAINER AND NOT
TO APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT
ENOUGH REFRIGERANT IN REFRIGERATION SYS-
TEM
If there is not enough refrigerant in the refrigerant system oil lu-
brication will be insufficient and compressor burnout may occur,
so that care to avoid this, necessary care should be taken.
7. DO NOT OPEN PRESSURE MANIFOLD VALVE WHILE
COMPRESSOR IS OPERATE
If the high pressure valve is opened, refrigerant flows in the re-
verse direction and could cause the charging cylinder to rup-
ture, so open and close the only low pressure valve.
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH
REFRIGERANT
If refrigerant is overcharged, it causes problems such as insuffi-
cient cooling, poor fuel economy, engine overheating etc.
Page 197 of 1897

C
No.Wire Connector Side
1
2
3
4
6
7
8
9
10
11
12
13
14
15
16ECU-IG No. 2 Fuse
Injector *
1
F (Panel) Fuse
Outside temperature sensor
ECM *
1
ABS ECU
Fuel sender gauge
Fuel sender gauge
Light control volume
RAD No. 1 Fuse Ground
ECU-ACC Fuse
-
Engine coolant temperature sendoer gauge
EFI
Heater control ECU *
117
18
19
20
21Speed control unit
Fuel sender gauge
-
Sender ground
Ground 22Starter Relay
D1
2
3
4
6
7
8
9
10
11
12
13
14
15
16-
Combination meter
-
-
-
- 17
18 -Low oil pressure warning switch *
2
Compressor lock sensor *2
A/C magnet switch
Evaporator temperature sensor *
2
A/C switch *2
A/C indicator *2
-
*1: Hi GradeECM
*2: Lo Grade 5
5Combination meter
Combination meter
Combination meter
Combination meter
Combination meter Combination meter
Combination meter
Combination meter
Combination meter
Combination meter
Combination meter
E
No.Wire Connector Side
1
2
3
4
6
7
8
9
10
11
12
13
14
15
16
17
18
19
205 1
2Compass sensor *1
Compass sensor *1
Compass sensor *1
-
-
-
-
-
-
-
-
-
- Compass sensor *
1
7
Compass sensor *1
- BODY ELECTRICALCOMBINATION METER
BE-47
1651 Author: Date:
2001 AVALON (RM808U)
Page 215 of 1897
I12532
Door Courtesy Switch
Fuel Sender Gauge
Light Failure Sensor Seat Belt Buckle Switch
Engine Coolant Temperature Sender Gauge
Park/Neutral Position Switch Low Oil Pressure Warning Switch
Occupant Detection Sensor
BE-42
- BODY ELECTRICALCOMBINATION METER
1646 Author: Date:
2001 AVALON (RM808U)
Page 308 of 1897

BE-4
- BODY ELECTRICALTROUBLESHOOTING
1608 Author: Date:
2001 AVALON (RM808U)
COMBINATION METER (Meter, Gauges and Illumination):
SymptomSuspect AreaSee page
Tachometer, Fuel Gauge and Engine Coolant Temperature Gauge
do not operate.
1. ECU-B Fuse
2. ECU-IG No. 2 Fuse
3. Meter Circuit Plate
4. Wire Harness
5. Multi Display-
-
BE-43
-
-
Speedometer does not operate.
1. Vehicle Speed Sensor (ABS - ECU)
2. Meter Circuit Plate
3. Wire Harness
4. Multi DisplayBE-53
BE-43
-
-
Tachometer does not operate.
1. EFI - ECU
2. Meter Circuit Plate
3. Wire Harness
4. Multi Display-
BE-43
-
-
Fuel Gauge does not operate or abnormal operation.
1. Fuel Receiver Gauge
2. Fuel Sender Gauge
3. Meter Circuit Plate
4. Wire HarnessBE-53
BE-53
BE-43
-
Engine Coolant Temperature Gauge does not operate or abnormal
operation.
1. Engine Coolant Temperature Receiver Gauge
2. Engine Coolant Temperature Sender Gauge
3. Meter Circuit Plate
4. Wire HarnessBE-53
BE-53
BE-43
-
All illumination lights do not light up.
1. Bulb
2. PANEL Fuse
3. Light Control Rheostat
4. Wire Harness-
-
BE-53
-
Brightness does not change even when rheostat turned.
1. Bulb
2. Rheostat
3. Wire Harness-
-
-
Only one illumination light does not light up.1. Bulb
2. Wire Harness-
-
COMBINATION METER (Warning Lights):
SymptomSuspect AreaSee page
Warning lights do not light up. (Except Discharge, Open Door and
SRS)
1. Bulb
2. GAUGE No. 1 Fuse
3. Meter Circuit Plate
4. Wire Harness-
-
BE-53
-
Low Oil Pressure warning light does not light up.
1. Multi Display
2. Bulb
3. Low Oil Pressure Warning Switch
4. Meter Circuit Plate
5. Wire Harness-
-
BE-53
BE-43
-
Fuel Level warning light does not light up.
1. Multi Display
2. Bulb
3. Fuel Sender Gause
4. Meter Circuit Plate
5. Wire Harness-
-
BE-53
BE-43
-
ABS warning light does not light up.
1. Bulb
2. ABS ECU
3. Wire Harness-
DI-210
-
Page 927 of 1897

A00477
Atmosphere
Cover
Exhaust GasPlatinum
Electrode
Solid Electrolyte
(Zirconia Element)
Platinum
Electrode
Heater
A/F Sensor Voltage
Air-Fuel Ratio
(V)
2.6 4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.4
12 13 14 15 16 17 18
Coating (Ceramic)
ECM Monitored
19
Housing
- DIAGNOSTICSENGINE
DI-43
199 Author: Date:
2001 AVALON (RM808U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way cata-
lytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio
must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The A/F sensor has the characteristic that provides output voltage* approximately proportional to the exist-
ing air-fuel ratio. The A/F sensor output voltage* is used to provide feedback for the ECM to control the air-
fuel ratio.
By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio
and control the proper injection time immediately. If the A/F sensor is malfunctioning, ECM is unable to per-
form accurate air-fuel ratio control.
The A/F sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the
ECM. When the intake air volume is low (the temp. of the exhaust gas is low), current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, A/F sensor output* does not
change when conditions (a), (b), (c) and (d) continue for at
least 1.5 min:
*: Output value changes at inside of the ECM only
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 - 100 km/h (25 - 62 mph)
(c) Throttle valve is not fully closed
(d) 140 sec. or more after starting engineOpen or short in A/F sensor (bank 1, 2 sensor 1) circuit
A/F sensor (bank 1, 2 sensor 1)
Air inducation system
Fuel pressure
Injector
Gas leakage on exhaust sytem
ECM
HINT:
After confirming DTC P0125, use the OBD II scan tool or TOYOTA hand-held tester to confirm voltage
output of the A/F sensor (bank 1, 2 sensor 1) from the CURRENT DATA.
The ECM controls the voltage of the AFR+, AFL+, AFR- and AFL- terminals of the ECM to the fixed
voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without the OBDII scan
tool or TOYOTA hand-held tester.
DI07M-14
Page 930 of 1897
DI-46
- DIAGNOSTICSENGINE
202 Author: Date:
2001 AVALON (RM808U)
3 Check for open and short in harness and connector between ECM and A/F sen-
sor (bank 1, 2 sensor 1) (See page IN-30).
NG Repair or replace harness or connector.
OK
4 Check resistance of A/F sensor heater (bank 1, 2 sensor 1) (See page SF-79).
NG Replace A/F sensor.
OK
5 Check air induction system (See page SF-1).
NG Repair or replace.
OK
6 Check fuel pressure (See page SF-6).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF-1).
OK
7 Check injector injection (See page SF-23).
NG Replace injector.
OK
Page 937 of 1897

DI-58
- DIAGNOSTICSENGINE
214 Author: Date:
2001 AVALON (RM808U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position sensor to monitor changes in
the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred.
When the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated, the
MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
DTC No.DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected during any particular
200 or 1,000 revolutionsOpen or short in engine wire
Connector connection
Vacuum hose connection
P0301
P0302
P0303For any particular 200 revolutions for engine, misfiring is de-
tected which can cause catalyst overheating (This causes MIL
to blink)
Ignition system
Injector
Fuel pressure
Mass air flow meter
Engine coolant tempsensorP0303
P0304
P0305
P0306For any particular 1,000 revolutions of engine, misfiring is de-
tected which causes a deterioration in emission (2 trip detec-
tion logic)
Engine coolant temp. sensor
Compression pressure
Valve clearance
Valve timing
ECM
DI07S-10
Page 941 of 1897
FI6588
FI6538
A00064
10 V
/Division10 V
/Division
GND GND
100 msec./Division (Idling)1 msec./Division (Idling)
Injection duration
(Magnification) Injector Signal Waveform
DI-62
- DIAGNOSTICSENGINE
218 Author: Date:
2001 AVALON (RM808U)
Reference: INSPECTION USING OSCILLOSCOPE
With the engine idling, check the waveform between terminals #10 - #60 and E01 of the ECM connector.
HINT:
The correct waveform is as shown.
OK Go to step 5.
NG
4 Check resistance of injector of misfiring cylinder (See page SF-19).
NG Replace injector.
OK
Check for open and short in harness and con-
nector between injector and ECM (See page
IN-30).
5 Check fuel pressure (See page SF-6).
NG Check and repair fuel pump, fuel pipe line and
filter (See page SF-1).