TOYOTA CAMRY 2000 Service Repair Manual

DI07E±06
± DIAGNOSTICSENGINE (1MZ±FE)
DI±221
456 Author: Date:
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
Engine does not crank (Does not start)1. Starter
2. Starter relayST±18
ST±20
No initial combustion (Does not start)
1. ECM power source circuit
2. Fuel pump control circuit
3. Engine control module (ECM)DI±369
DI±374
IN±31
No complete combustion (Does not start)1. Fuel pump control circuitDI±374
Engine cranks normally (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit
3. CompressionDI±384
DI±374
EM±3
Cold engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI±384
DI±374
Hot engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI±384
DI±374
High engine idle speed (Poor idling)1. A/C signal circuit (Compressor Circuit)
2. ECM power source circuitAC±88
DI±369
Low engine idle speed (Poor idling)1. A/C signal circuit (Compressor Circuit)
2. Fuel pump control circuitAC±88
DI±374
Rough idling (Poor idling)1. Compression
2. Fuel pump control circuitEM±3
DI±374
Hunting (Poor idling)1. ECM power source circuit
2. Fuel pump control circuitDI±369
DI±374
Hesitation/Poor acceleration (Poor driveability)1. Fuel pump control circuit
2. A/T faultyDI±374
DI±453
Surging (Poor driveability)1. Fuel pump control circuitDI±374
Soon after starting (Engine stall)1. Fuel pump control circuitDI±374
During A/C operation (Engine stall)1. A/C signal circuit (Compressor Circuit)
2. Engine control module (ECM)AC±88
IN±31
Unable to refuel/Difficult to refuel1. ORVR systemEC±6

DI07F±06
A00435
B+
Thermistor
Power Transistor
Platinum Hot wire
B
Output
Platinum Hot
Wire A
Voltage
Thermistor
FI6929
S05741
DI±222
± DIAGNOSTICSENGINE (1MZ±FE)
457 Author: Date:
CIRCUIT INSPECTION
DTC P0100 Mass Air Flow Circuit Malfunction
CIRCUIT DESCRIPTION
The mass air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire,
thermistor and a control circuit installed in a plastic housing. The hot wire air flow meter works on the principle
that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the
intake air temperature.
The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This
current flow is then measured as the output voltage of the mass air flow meter.
The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power
transistor controlled so that the potential of A and B remains equal to maintain the set temperature.
DTC No.DTC Detecting ConditionTrouble Area
P0100Open or short in mass air flow meter circuit with more than 3
sec. engine speed 4,000 rpm or less
Open or short in mass air flow meter circuit

Mass air flow meter

ECM
If the ECM detects DTC 0100 it operates the fail±safe function, keeping the ignition timing and injection vol-
ume constant and making it possible to drive the vehicle.
HINT:
After confirming DTC P0100, use the OBD II scan tool or TOYOTA hand±held tester to confirm the mass
air flow ratio from ºCURRENT DATAº.
Mass Air Flow Value (gm/sec.)Malfunction
0.0
Mass air flow meter power source circuit open

VG circuit open or short
271.0 or more
E2G circuit open

A06156
Engine Room J/B
EFI Relay
Junction
Connector
J20
Junction
Connector EFI
2A
2K2J
2C B
EB
7 1
2
5
13
2
F9
F4
11
B±G
Mass Air
Flow Meter
B±Y
B±Y
B±Y
R
R±BECM
E2GVG
E2 P 5B
B
9
4 A A
5
3
8
W±B
E10 B±W
E7 10
19
MRELB+ E10 Junction
ConnectorJ35 J36
A
A
B±W
Fusible
Link
Block
FL
MAIN
Battery
J27J28
II3
± DIAGNOSTICSENGINE (1MZ±FE)
DI±223
458 Author: Date:
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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.

A00436
ON
4 (+)
BE6653
S05337
DI±224
± DIAGNOSTICSENGINE (1MZ±FE)
459 Author: Date:
1 Connect OBD II scan tool or TOYOTA hand±held tester, and read value of mass
air flow rate.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand±held tester main switch
ON.
(c) Start the engine.
CHECK:
Read mass air flow rate on the OBD II scan tool or TOYOTA hand±held tester.
RESULT:
Type IType II
Mass air flow rate (gm/sec.)0.0271.0 or more
Type I Go to step 2.
Type II Go to step 5.
2 Check voltage of mass air flow meter power source.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminal 4 of mass air flow meter con-
nector and body ground.
OK:
Voltage: 9 ~ 14 V
NG Check for open in harness and connector
between EFI main relay (Marking: EFI) and
mass air flow meter (See page IN±31).
OK

A02017
VG (+)
± DIAGNOSTICSENGINE (1MZ±FE)
DI±225
460 Author: Date:
3 Check voltage between terminal VG of ECM connector and body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF±73).
(b) Start the engine.
CHECK:
Measure voltage between terminal VG of the ECM connector
and body ground while engine is idling.
OK:
Voltage:
1.1 ~ 1.5 V (P or N position and A/C switch OFF)
OK Check and replace ECM (See page IN±31).
NG
4 Check for open and short in harness and connector between mass air flow meter
and ECM (See page IN±31).
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.

A02018
E2G
DI±226
± DIAGNOSTICSENGINE (1MZ±FE)
461 Author: Date:
5 Check continuity between terminal E2G of ECM and body ground.
PREPARATION:
Remove the glove compartment (See page SF±73).
CHECK:
Check continuity between terminal E2G of the ECM connector
and body ground.
OK:
Continuity (1 W or less)
NG Check and replace ECM (See page IN±31).
OK
6 Check for open in harness and connector between mass air flow meter and ECM
(See page IN±31).
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.

± DIAGNOSTICSENGINE (1MZ±FE)
DI±227
462 Author: Date:
DTC P0101 Mass Air Flow Circuit Range/Performance
Problem
CIRCUIT DESCRIPTION
Refer to DTC P0100 (Mass Air Flow Circuit Malfunction) on page DI±222.
DTC No.DTC Detecting ConditionTrouble Area
P0101
Conditions (a), (b) and (c) continue 10 sec. or more with
engine speed NE < 900:
(2 trip detection logic)
(a) Throttle valve fully closed
(b) Mass air flow meter output  2.2 V
(c) THW  70°C

Mass air flow meterP0101
Conditions (a) and (b) continue 10 sec. or more with engine
speed 1,500 rpm or more:
(2 trip detection logic)
(a) VTA  0.63 V
(b) Mass air flow meter output
1.06 V

Mass air flow meter
WIRING DIAGRAM
Refer to DTC P0100 (Mass Air Flow Circuit Malfunction) on page DI±222.
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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Are there any other codes (besides DTC P0101) being output?
NO Replace mass air flow meter.
YES
Go to relevant DTC chart.
DI07G±06

FI4741
(fig. 1)
Acceptable
Resistance kW
± 20 0 20 40 60 80 100
(± 4) 32 68 104 140 176 212 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
Te m p .°C (F°)
DI±228
± DIAGNOSTICSENGINE (1MZ±FE)
463 Author: Date:
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the air flow meter and senses the intake air temperature.
A thermistor built in the sensor changes the resistance value according to the intake air temperature.
The lower the intake air temperature, the greater the thermistor resistance value, and the higher the intake
air temperature, the lower the thermistor resistance value (See Fig. 1).
The intake air temperature sensor is connected to the ECM. The 5 V power source voltage in the ECM is
applied to the intake air temperature sensor from the terminal THA via resistor R.
That is, the resistor R and the intake air temperature sensor are connected in series. When the resistance
value of the intake air temperature sensor changes in accordance with changes in the intake air temperature,
the potential at terminal THA also changes. Based on this signal, the ECM increases the fuel injection vol-
ume to improve driveability during cold engine operation.
If the ECM detects the DTC P0110, it operates the fail±safe function in which the intake air temperature is
assumed to be 20°C (68°F).

Intake air temp.
°C (°F)Resistance
(kW)Voltage
(V)
±20 (±4)16.04.3
0 (32)5.93.4
20 (68)2.52.4
40 (104)1.11.4
60 (140)0.60.9
80 (176)0.30.5
100 (212)0.10.2
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit

Open or short in intake air temp. sensor circuit

Intake air temp. sensor (built into mass air flow meter)

ECM
HINT:
After confirming DTC P0110, use the OBD II scan tool or TOYOTA hand±held tester to confirm the intake
air temp. from ºCURRENT DATAº.
Temp. DisplayedMalfunction
±40°C ( ±40°F )Open circuit
140°C ( 284°F ) or moreShort circuit
DI07H±07

FI6448
Intake Air Temp. Sensor
(Inside the Mass Air Flow Meter)ECM
5 V
THA
E2
E1 1
2R
L±Y
BR
E10E1022
18
± DIAGNOSTICSENGINE (1MZ±FE)
DI±229
464 Author: Date:
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs P0110 (Intake Air Temp. Circuit Malfunction), P0115 (Engine Coolant Temp. Circuit Malfunc-
tion), P0120 (Throttle/Pedal Position Sensor/Switch ºAº Circuit Malfunction) and P1410 (EGR Valve
Position Sensor Circuit Malfunction) are output simultaneously, E2 (Sensor Ground) may be open.

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 warmed up or not, the air±fuel
ratio lean or rich, etc. at the time of the malfunction.

A00210
ON
Intake Air
Temp. Sensor
ECM
5 V
E2THA
1
2
E10 E10
22
18
DI±230
± DIAGNOSTICSENGINE (1MZ±FE)
465 Author: Date:
1 Connect OBD II scan tool or TOYOTA hand±held tester, and read value of
intake air temp.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand±held tester main switch
ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand±held tester.
OK:
Same as actual intake air temp.
HINT:

If there is open circuit, OBD II scan tool or TOYOTA hand±held tester indicates ±40°C (-40°F).

If there is short circuit, OBD II scan tool or TOYOTA hand±held tester indicates 140°C (284°F) or more.
NG ±40°C (±40°F) ... Go to step 2.
140°C (284°F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI±197).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Connect sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA
hand±held tester.
OK:
Temp. value: 1405C (2845F) or more
OK Confirm good connection at sensor.
If OK, replace mass air flow meter.
NG