TROUBLESHOOTING
ENGINE COOLING
14-10
STEP 12. Check the fan controller at engine-ECU
connector C-121.
AC505254
16
25
10
24
1
9
24
27
13
26
11
3
12
2829
1415
3031
1718
3332
6
20
5
19 21
35
34
8
23
7
22
JAE
AB
Connector: C-121 <LHD>
Harness side
C-121 (GR)
Engine-ECU
AC505255
16
25
10
24
1
9
24
27
13
26
11
3
12
2829
1415
3031
1718
3332
6
20
5
19 21
35
34
8
23
7
22
JAE
AB
Connector: C-121 <RHD>
Harness side
C-121 (GR)
Engine-ECU
(1) Do not disconnect engine-ECU connector C-121.
(2) Pull out terminal No.18.
(3) Turn the ignition switch to the "ON" position.
Q: Does the cooling fan motor operate?
YES : Replace the engine-ECU. Then go to Step
13
.
NO : Replace the fan controller. Then go to Step
13
.
STEP 13. Check the symptoms.
Q: Does the cooling fan operate correctly?
YES : The procedure is complete.
NO : Return to Step 1.
INSPECTION PROCEDURE 2: Cooling fan does not change speed or does not stop
NOTE: If the engine coolant temperature reaches 110
°
C or higher, the cooling fan control runs the cooling fan
for up to 5 minutes even after the ignition switch is turned to the "LOCK" (OFF) position (the fan stops its rota
-
tion when the engine coolant temperature decreases to 110
°
C or lower).
COOLING FAN DRIVE CIRCUIT
Refer to P.14-4.
CIRCUIT OPERATION
• The fan controller is powered from fusible link
No.2.
• The engine-ECU judges the required revolution
speed of cooling fan motor using the input signals
transmitted from A/C switch, vehicle speed sen
-
sor and engine coolant temperature sensor. The
engine-ECU activates the fan controller to drive
the cooling fan motor.
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