2001 TOYOTA PRIUS air conditioning

I18162
ON
SGTR
TR
(±) (+)
I00317
DI±882
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals TR and SGTR of A/C amplifier connector.
PREPARATION:
(a) Remove center cluster module control with connectors
still connected.
(b) Turn the ignition switch ON.
CHECK:
Check voltage between terminals TR and SGTR of A/C amplifi-
er connector at each temperature.
OK:
at 25 °C (77 °F) : 1.8 ± 2.2 V
at 40 °C (104 °F) : 1.2 ± 1.6 V
HINT:
As the temperature increases, the voltage decreases.
NG Go to step 2.
OK
Proceed to next circuit inspection shown on problem symptoms table (See page DI±874). Howev-
er, if DTC 11 is output, check and replace A/C amplifier.
2 Check room temperature sensor.
PREPARATION:
Remove room temperature sensor (See page AC±60).
CHECK:
Check resistance between terminals 1 and 2 of room tempera-
ture sensor connector at each temperature.
OK:
at 25 °C (77 °F) : 1.6 ± 1.8 kW
at 40 °C (104 °F) : 0.5 ± 1.7 kW
HINT:
As the temperature increases, the resistance decreases.
NG Replace room temperature sensor.
OK

± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±883
2001 PRIUS (RM778U)
3 Check harness and connector between A/C amplifier and room temperature sen-
sor (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.

I18377
A/C amplifier
A7
Ambient Temp.
SensorMPX+
A71
1 2 15
MP2+ A74 3 2Combination Meter
MPX+
MPX±GR
GR±B B8 MPX+
MPX±16
B8 Body ECU
GR
1MPX TAM
2MPX E2
14
E10
13
E1023
E8
18
E8 ECM
W±GIA25
IK12W±G GR±L11
4 G1 Gateway ECU
GR±B
2MPD
1MPD
C11
C11
BR
BR±W G1 G1 DI±884
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
DTC 12 Ambient Temperature Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the ambient temperature and sends the appropriate signals to the A/C amplifier.
DTC No.Detection ItemTrouble Area

Ambient temperature sensor

Harness or connector between ambient temperature sensor
12Open or short in ambient temperature sensor circuit

Harness or connector between ambient tem erature sensor
and ECM

ECM
ECM

Harness or connector between ECM and A/C amplifier

A/C amplifier.
WIRING DIAGRAM
DI7S6±01

I18175
ON
E2
TA M
(±) (+)
ECM terminals
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±885
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals TAM and E2 of ECM connector.
PREPARATION:
(a) Remove ECM with connectors still connected.
(b) Turn ignition switch ON.
CHECK:
Check voltage between terminals TAM and E2 of ECM connec-
tor at each temperature .
OK:
Voltage
at 25 °C (77 °F) : 1.35 ± 1.75 V
at 40 °C (104 °F) : 0.85 ± 1.25 V
HINT:
As the temperature increases, the voltage decreases.
NG Go to step 2.
OK
Proceed to the next circuit inspection shown on problem symptoms table (See page DI±874).
However, if DTC 12 is displayed, check and replace A/C amplifier.

I05262
1
2
DI±886
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
2 Check ambient temperature sensor.
PREPARATION:
Disconnect ambient temperature sensor connector.
CHECK:
Check resistance between terminals 1 and 2 of ambient tem-
perature sensor connector at each temperature.
OK:
Resistance
at 25 °C (77 °F) : 1.6 ± 1.8 kW
at 40 °C (104 °F) : 0.5 ± 0.7 kW
HINT:
As the temperature increases, the resistance decreases.
NG Replace ambient temperature sensor.
OK
Check multiplex communication system (See page DI±750).

I18376
A/C Amplifier
W
SGTE 2
A9
1
2 A13
A/C Thermistor
W
TE 1
A9
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±887
2001 PRIUS (RM778U)
DTC 13 Evaporator Temperature Sensor Circuit
CIRCUIT DESCRIPTION
This sensor detects the temperature inside the cooling unit and sends the appropriate signals to the A/C
amplifier.
DTC No.Detection ItemTrouble Area

Evaporator temperature sensor.
13Open or short in evaporator temperature sensor circuit.
Harness or connector between evaporator temperature sen-
sor and A/C amplifiersor and A/C amplifier.

A/C amplifier.
WIRING DIAGRAM
DI7S7±01

I18161
ON
SGTE TE
(±) (+)
AC0175
Thermometer
Ice
ThermistorOhmmeter
More
than
10 cm
(3.94 in.)
DI±888
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
1 Check voltage between terminals TE and SGTE of A/C amplifier connector.
PREPARATION:
(a) Remove center cluster module control with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals TE and SGTE of A/C am-
plifier connector at each temperature.
OK:
Voltage
at 0 °C (32 °F) : 2.0 ± 2.4 V
at 15 °C (59 °F) : 1.4 ± 1.8 V
HINT:
As the temperature increases, the voltage decreases.
NG Go to step 2.
OK
Proceed to next circuit inspection shown on problem symptoms table (See page DI±874). Howev-
er, if DTC 13 is displayed, check and replace A/C amplifier.
2 Check evaporator temperature sensor.
PREPARATION:
Remove evaporator temperature sensor (See page AC±27).
CHECK:
Check resistance between terminals 1 and 2 of evaporator tem-
perature sensor connector at each temperature.
OK:
Resistance
at 0 °C (32 °F) : 4.6. ± 5.1 kW
at 15 °C (59 °F) : 2.1 ± 2.6 kW
HINT:
As the temperature increases, the voltage decreases.
NG Replace evaporator temperature sensor.
OK

± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±889
2001 PRIUS (RM778U)
3 Check harness and connector between A/C amplifier and evaporator tempera-
ture sensor (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.