TOYOTA CAMRY 1999 Service Repair Manual

A00310
Engine Coolant Temp.
Sensor
2
1ECM
G±B
BR4
E5
E595 V
THW
E2
E1 R DI±30
± DIAGNOSTICSENGINE
DTC P0115 Engine Coolant Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the
engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the intake air temperature circuit
malfunction shown on page DI±26.
If the ECM detects the DTC P0115, it operates fail safe function in which the engine coolant temperature
is assumed to be 80°C (176°F).
DTC No.Detection ItemTrouble Area
P0115Open or short in engine coolant temp. sensor circuit

Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
HINT:
After confirming DTC P0115, use the OBD II scan tool or TOYOTA hand±held tester to confirm the engine
coolant temp. from the CURRENT DATA.
Temp. DisplayedMalfunction
±40°C (±40°F)Open circuit
140°C (284°F) or moreShort circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs P0105, P0106, P0110, P0115, P0120, P0180 and P0190 are output simultaneously, E2 (sen-
sor 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 was warmed up or not, the air±fuel
ratio was lean or rich, etc. at the time of the malfunction.
DI00P±07

A00395
ECM ON
Engine Coolant
Temp. Sensor
2
14
9
THW
E25 V
E1 E5
E5
± DIAGNOSTICSENGINE
DI±31
1 Connect OBD II scan tool or TOYOTA hand±held tester, and read value of engine
coolant temperature.
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 the temperature value on the OBD II scan tool or TOYOTA hand±held tester.
OK:
Same as actual engine coolant temperature.
HINT:

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

If there is open 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±3).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temperature sensor con-
nector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand±held tester.
OK:
Temperature value: 140°C (284°F) or more
OK Confirm good connection at sensor. If OK, re-
place engine coolant temperature sensor.
NG

A03012A09258
ON
Engine Coolant
Temp. SensorECM
THW
E2
4
2
15 V
THW
E1 E5
E5
9E2
A00397
ON
Engine Coolant
Temp. Sensor
4
9ECM
E5
E5THW
E25 V
E1
DI±32
± DIAGNOSTICSENGINE
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Connect between terminals THW and E2 of the ECM con-
nector.
HINT:
The engine coolant temperature sensor connector is discon-
nected. Before checking, do a visual and contact pressure
check for the ECM connector (See page IN±29).
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand±held tester.
OK:
Temperature value: 140°C (284°F) or more
OK Open in harness between terminals E2 or THW,
repair or replace harness.
NG
Confirm good connection at ECM. If OK,
check and replace ECM (See page IN±29).
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the engine coolant temperature sensor con-
nector.
(b) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand±held tester.
OK:
Temperature value: ± 40°C (± 40°F)
OK Replace engine coolant temperature sensor.
NG

A03011A09257
Engine Coolant
Temp. Sensor
THW
E25 V
E1
ON
E5 Connector
± DIAGNOSTICSENGINE
DI±33
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Disconnect the E5 connector from the ECM.
HINT:
The engine coolant temp. sensor connector is disconnected.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand±held tester.
OK:
Temperature value: ±40°C (±40°F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN±29).

DI±34
± DIAGNOSTICSENGINE
DTC P0116 Engine Coolant Temp. Circuit Range/Perfor-
mance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI±30.
DTC No.DTC Detecting ConditionTrouble Area
If THW < ±7°C (19.4°F) or THA < ±7°C (19.4°F) 20 min. or
more after starting engine, engine coolant temp. sensor value
is ±10°C (±50°F)* or less (2 trip detection logic)
P0116
When THW 35°C (95°F) and 60°C (140°F), THA

±6.7°C (19.9°F) when starting the engine, conditions (a) and
(b) continue: (2 trip detection logic)
(a) Vehicle speed is changing (Not stable)
(b) Water temperature change is lower than 3°C (37.4°F) from
water temperature since when starting the engine
Cooling system

Engine coolant temp. sensor
INSPECTION PROCEDURE
HINT:

If DTCs P0105, P0106, P0110, P0115, P0120, P0180 and P0190 are output simultaneously, engine
coolant temperature sensor circuit may be open. Perform troubleshooting of DTC P0115 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.
1 Are there any other codes (besides DTC P0116) being output?
YES Go to relevant DTC chart.
NO
2 Check thermostat (See Pub. No. RM654U, page CO±10).
NG Replace thermostat.
OK
Replace engine coolant temperature sensor.
DI00Q±07

P24296
Throttle Position
Sensor
VC
VTA
E2ECM
A09396
Throttle Position Sensor
ECM
E5
E5 1
3
2Y
LG
BR1
11
9VC
VTA
E25 V
E5
± DIAGNOSTICSENGINE
DI±35
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle. When the throttle valve
is fully closed, a voltage of approximately 0.3 ± 0.8 V is applied
to terminal VTA of the ECM. The voltage applied to the termi-
nals VTA of the ECM increases in proportion to the opening
angle of the throttle valve and becomes approximately 3.2 ± 4.9
V when the throttle valve is fully opened. The ECM judges the
vehicle driving conditions from this signal input from terminal
VTA, and uses it as one of the conditions to decide the air±fuel
ratio correction, power increase correction and fuel±cut control
etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) continues with more than 5 sec.
(a) VTA < 0.1 V
(b) VTA > 4.9 V
Open or short in throttle position sensor circuit

Throttle position sensor

ECM
HINT:
After confirming DTC P0120, use the OBD II scan tool or TOYOTA hand±held tester to confirm the throttle
valve opening percentage.
Throttle valve opening position expressed as percentageTblAThrottle valve fully closedThrottle valve fully openTrouble Area
0 %0 %
VC circuit open

VTA circuit open or ground short
Approx. 100 %Approx. 100 %
E2 circuit open
WIRING DIAGRAM
DI00R±07

FI7052
A00369
ON
VC
(+)
(±)
DI±36
± DIAGNOSTICSENGINE
INSPECTION PROCEDURE
HINT:

If DTCs P0105, P0106, P0110, P0115, P0120, P0180 and P0190 are output simultaneously, E2 (sen-
sor 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 was warmed up or not, the air±fuel
ratio was lean or rich, etc. at the time of the malfunction.
1 Connect OBD II scan tool or TOYOTA hand±held tester, and read the throttle
valve opening percentage.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tes-
ter 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 the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening position
expressed as percentage
Fully openApprox. 70 %
Fully closedApprox. 10 %
OK Check for intermittent problems
(See page DI±3).
NG
2 Check voltage between terminal VC of throttle position sensor connector and
body ground.
PREPARATION:
(a) Disconnect the throttle position sensor connector.
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal VC of the throttle posi-
tion connector and body ground.
OK:
Voltage: 4.5 ± 5.5 V
NG Go to step 5.
OK

A09283BE6653
A09264
ON
VTA
E2
(+)
(±)
BE6653A03008A09254
ON
VC
E2
(±)
(+)
± DIAGNOSTICSENGINE
DI±37
3 Check throttle position sensor (See Pub. No. RM654U, page SF±29).
NG Replace throttle position sensor.
OK
4 Check voltage between terminals VTA and E2 of ECM connector.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals VTA and E2 of the ECM
connector.
OK:
Throttle valveVoltage
Fully closed0.3 ± 1.0 V
Fully open3.2 ± 4.9 V
NG Check for open and short in harness and con-
nector in VTA and E2 circuits between ECM and
throttle position sensor (See page IN±29).
OK
Check and replace ECM (See page IN±29).
5 Check voltage between terminals VC and E2 of ECM connector.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals VC and E2 of the ECM
connector.
OK:
Voltage: 4.5 ± 5.5 V
NG Check and replace ECM (See page IN±29).

DI±38
± DIAGNOSTICSENGINE
OK
Check for open in harness and connector in
VC circuit between ECM and throttle position
sensor (See page IN±29).

± DIAGNOSTICSENGINE
DI±39
DTC P0121 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Range/Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0120 on page DI±35.
DTC No.Detection ItemTrouble Area
P0121
After vehicle speed has been exceeded 30 km/h (19 mph)
even once, output value of throttle position sensor is out of
applicable range while vehicle speed between 30 km/h (19
mph) and 0 km/h (0 mph) (2 trip detection logic)

Throttle position sensor
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 Are there any other codes (besides DTC P0121) being output?
YES Go to relevant DTC chart.
NO
Replace throttle position sensor.
DI00S±06