TROUBLESHOOTING
ENGINE COOLING14-5
TROUBLESHOOTING
INSPECTION CHART FOR TROUBLE
SYMPTOMS
M1141005600360
MB991223
A: MB991219
B: MB991220
C: MB991221
D: MB991222 Harness set
A: Test harness
B: LED harness
C: LED harness
adapter
D: ProbeMaking voltage and
resistance measurement
during troubleshooting
A: Connector pin contact
pressure inspection
B: Power circuit inspection
C: Power circuit inspection
D: Commercial tester
connection
MB991871 LLC changer Coolant refilling Tool Number Name Use
MB991223
A
B
C
D
AC
MB991871
Trouble symptom Inspection
procedure No.Reference page
Cooling fan (L.H.) and Cooling fan (R.H.) <4G1 (Vehicles with
A/C)> or A/C condenser fan <4G6> do not operate 1
P.14-6
Cooling fan (L.H.) and Cooling fan (R.H.) <4G1 (Vehicles with
A/C)> or A/C condenser fan <4G6> do not change speed or stop2
P.14-16
Cooling fan (L.H.) does not operate {When cooling fan (R.H.)
<4G1> or A/C condenser fan <4G6> operate} 3
P.14-20
Cooling fan (R.H.) <4G1> or A/C condenser fan <4G6> does not
operate {When cooling fan (L.H.) operate} 4
P.14-21
ON-VEHICLE SERVICE
ENGINE COOLING14-23
5. Apply the designated sealant to the screw area of
the cylinder block drain plug, and then tighten to
the standard torque.
Specified sealant: 3M Nut Locking Part
No.4171 or equivalent
Tightening torque:
40 ± 5 N⋅m <4G1>
44 ± 5 N⋅m <4G6>
6. Securely tighten the drain plug of the radiator.
7. Reinstall the radiator condenser tank.
CAUTION
Do not use alcohol or methanol anti-freeze or any
engine coolants mixed with alcohol or methanol
anti-freeze. The use of an improper anti-freeze
can cause corrosion of the aluminium
components.
8. By referring to the section on coolant, select an
appropriate concentration for safe operating
temperature within the range of 30 to 60%. Use
special tool LLC changer (MB991871) to refill the
coolant. A convenient mixture is a 50% water and
50% antifreeze solution (freezing point: −31°C).
Recommended antifreeze: DIAQUEEN SUPER
LONG LIFE COOLANT or equivalent
Quantity:
5.0 L <4G1>
7.0 L <4G6>
NOTE: For how to use special tool MB991871,
refer to its manufacturer’s instructions.9. Reinstall the radiator cap.
10.Start the engine and let it warm up until the
thermostat opens.
11.After repeatedly revving the engine up to 3,000
r/min several times, then stop the engine.
12.Remove the radiator cap after the engine has
become cold, and pour in coolant up to the brim.
Reinstall the cap.
CAUTION
Do not overfill the radiator condenser tank.
13.Add coolant to the radiator condenser tank
between the "F" and "L" mark if necessary.
CONCENTRATION MEASUREMENTM1141001100352
Measure the temperature and specific gravity of the
engine coolant to check the antifreeze concentration.
Standard value: 30 − 60% (allowable
concentration range)
Recommended antifreeze: DIAQUEEN SUPER
LONG LIFE COOLANT or equivalent
CAUTION
If the concentration of the anti-freeze is below
30%, the anti-corrosion property will be
adversely affected. In addition, if the
concentration is above 60%, both the
anti-freezing and engine cooling properties will
decrease, affecting the engine adversely. For
these reasons, be sure to maintain the
concentration level within the specified range.
COOLING FAN MOTOR DRIVE CONTROL
UNIT CHECK
M1141006100216
1. Remove the cooling fan motor drive control unit
connector.
2. Turn the ignition switch to the "ON" position, and
measure the voltage between terminal 1 and 3 at
the harness side connector.
Standard value: system voltage
AC200625
Cylinder block
drain plug
AC
AC303612AB
MB991871
AIR HOSE
AC103195
Y1716AU
1 23
AC
Cooling fan motor
drive control unit
