Mitsubishi Eclipse. Manual - part 653

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-15

STEP 2. Check the harness wire between fan control relay 
connector A-09X (terminal number 2) and fan controller 
connector A-30 (terminal number 3).
Q: Are the harness wire between fan control relay 

connector A-09X (terminal number 2) and fan controller 
connector A-30 (terminal number 3) damaged?
YES : Repair or replace the part, then go to Step 6.
NO :  Go to Step 3.

STEP 3. Check the circuit at ECM connector C-49 (terminal 
number 21) <2.4L-M/T>, C-51 (terminal number 18) 
<3.0L-M/T> or PCM connector C-50 (terminal number 18) 
<2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T>.
(1) Connect ECM connector C-49 (terminal number 21) 

<2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or 
PCM connector C-50 (terminal number 18) <2.4L-A/T>, 
C-52 (terminal number 18) <3.0L-A/T>.

(2) Start the engine and run it at idle. [Engine coolant 

temperature: 80

°C (176°F) or less]

(3) Measure the voltage between terminal number 21 

<2.4L-M/T> or 18 <2.4L-A/T, 3.0L> and ground.

Q: Is the voltage 0 

− 0.3 volt when radiator fan is not 

operating?
YES : Go to Step 6.
NO :  Go to Step 4.

STEP 4. Check the harness wire between ECM connector 
C-49 (terminal number 21) <2.4L-M/T>, C-51 (terminal 
number 18) <3.0L-M/T> or PCM connector C-50 (terminal 
number 18) <2.4L-A/T>, C-52 (terminal number 18) 
<3.0L-A/T> and fan controller connector A-30 (terminal 
number 2).
NOTE: If intermediate connector C-07 (terminal number 6) is 
damaged, repair or replace it. Refer to GROUP 00E, Harness 
Connector Inspection 

P.00E-2

.

AC102598

CONNECTOR: A-09X

A-09X

AC

AC000270 AB

CONNECTOR: A-30

RADIATOR
FAN

AC000257

<2.4L-M/T>

<2.4L-A/T, 3.0L>

CONNECTOR C-49

CONNECTOR C-50, C-51, C-52

AC

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-16

Q: Are the harness wires between ECM connector C-49 

(terminal number 21) <2.4L-M/T>, C-51 (terminal number 
18) <3.0L-M/T> or PCM connector C-50 (terminal number 
18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T> 
and fan controller connector A-30 (terminal number 2) 
damaged?
YES : Repair or replace them, then go to Step 6.
NO :  Go to Step 5.

STEP 5. Check the fan controller at ECM connector C-49 
(terminal number 21) <2.4L-M/T>, C-51 (terminal number 
18) <3.0L-M/T> or PCM connector C-50 (terminal number 
18) <2.4L-A/T>, C-52 (terminal number 18) <3.0L-A/T>.
(1) Disconnect ECM connector C-49 (terminal number 21) 

<2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or 
PCM connector C-50 (terminal number 18) <2.4L-A/T>, 
C-52 (terminal number 18) <3.0L-A/T>.

(2) Pull out the terminal number <2.4L-M/T> or 18 <2.4L-A/T, 

3.0L> and connect it to the body ground.

(3) Reconnect ECM connector C-49 (terminal number 21) 

<2.4L-M/T>, C-51 (terminal number 18) <3.0L-M/T> or 
PCM connector C-50 (terminal number 18) <2.4L-A/T>, 
C-52 (terminal number 18) <3.0L-A/T> with pin 21 
<2.4L-M/T> or 18 <2.4L-A/T, 3.0L> still removed.

(4) Turn the ignition switch to the " ON" position.
Q: Do the radiator fan motor and condenser fan motor 

stop?
YES : Replace the ECM <M/T> or PCM <A/T>. Then go to 

Step 6.

NO :  Replace the radiator fan motor and fan controller 

assembly. Then go to Step 6 .

STEP 6. Check the symptoms.
Q: Do the radiator fan and condenser fan operate 

correctly?
YES : This diagnosis is complete.
NO :  Return to Step 1.

INSPECTION PROCEDURE 5: Radiator Fan does not Operate

.

TECHNICAL DESCRIPTION
The cause could be a malfunction of the radiator fan 
motor or an open circuit between the fan controller 
and the radiator fan motor.

.

TROUBLESHOOTING HINTS

• Malfunction of radiator fan motor

• Malfunction of fan controller

.

AC000245 AE

CONNECTOR: 
       C-49 <2.4L-M/T>, C-50 <2.4L-A/T>
       C-51 <3.0L-M/T>, C-52 <3.0L-A/T>

ECM <M/T>
OR
PCM <A/T>

AC000257

<2.4L-M/T>

<2.4L-A/T, 3.0L>

CONNECTOR C-49

CONNECTOR C-50, C-51, C-52

AC

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-17

DIAGNOSIS
Replace the radiator fan motor and fan controller assembly.
Q: Does the radiator fan operate correctly?

YES : There is no action to be taken?
NO :  Repair the wiring harness between the fan controller 

and the radiator fan motor.

INSPECTION PROCEDURE 6: Condenser Fan does not Operate

.

Radiator Fan and Condenser Fan Drive Circuit
Refer to 

P.14-6

.

.

CIRCUIT OPERATION

• The fan controller is powered from fusible link 

number 2.

• The ECM <M/T> or PCM <A/T> judges the 

required revolution speed of radiator fan motor 
and condenser fan motor using the input signals 
transmitted from A/C switch, automatic compres-
sor controller, vehicle speed sensor and engine 
coolant temperature sensor. The ECM <M/T> or 
PCM <A/T> activates the fan controller to drive 
the radiator fan motor and condenser fan motor.

.

TECHNICAL DESCRIPTION
The cause could be a malfunction of the condenser 
fan motor or of the fan controller.

.

TROUBLESHOOTING HINTS

• Malfunction of condenser fan motor

• Malfunction of fan controller

.

DIAGNOSIS

STEP 1. Check the condenser fan motor.
Refer to GROUP 55, Condenser and Condenser Fan Motor 

P.55-50

.

Q: Is the condenser fan in good condition?

YES : Go to Step 2.
NO :  Replace the fan motor, then go to Step 3.

STEP 2. Check the fan controller.
Refer to 

P.14-20

.

Q: Is the fan controller in good condition?

YES : Go to Step 3.
NO :  Replace the fan controller, then go to Step 3.

STEP 3. Check the symptoms.
Q: Does the condenser fan operate correctly?

YES : This diagnosis is complete.
NO :  Return to Step1.

ON-VEHICLE SERVICE

TSB Revision

COOLING SYSTEM

14-18

ON-VEHICLE SERVICE

ENGINE COOLANT LEAK CHECK

M1141001000173

WARNING

When pressure testing the cooling system, slowly 
release cooling system pressure to avoid getting 
burned by hot coolant.

CAUTION

• Be sure to completely clean away any moisture from 

the places checked.

• When the tester is taken out, be careful not to spill any 

coolant from it.

• Be careful when installing and removing the tester and 

when testing not to deform the filler neck of the radia-
tor.

1. Check that the coolant level is up to the filler neck. Install a 

radiator cap tester and apply 160 kPa (23 psi) pressure, and 
then check for leakage from the radiator hose or 
connections.

2. If there is leakage, repair or replace the appropriate part.

RADIATOR CAP PRESSURE CHECK

M1141001300378

NOTE: Be sure that the cap is clean before testing, since rust 
or other foreign material on the cap seal will cause an improper 
indication.
1. Use a cap adapter to attach the cap to the tester.
2. Increase the pressure until the indicator of the gauge stops 

moving.

Minimum limit: 83 kPa (12 psi)
Standard value: 93 

− 123 kPa (14 − 18 psi)

3. Replace the radiator cap if the reading does not remain at or 

above the limit.

ENGINE COOLANT REPLACEMENT

M1141001200423

1. Turn the ignition switch to the "ON" position, and then rotate 

the heater control to the "MAX HOT" position.

2. Turn the ignition switch to the "LOCK" (OFF) position.

ACX01844 AB

CAP ADAPTER

ADAPTER

ACX01845 AB

CAP ADAPTER