Charge Air Cooler Fan Control
SYSTEM DESCRIPTION
Crankshaft position sensor (TDC)cEngine speed
ECM
cCharge air cooler fan relayCharge air temperature sensorcCharge air temperature
Ignition switch
cStart signal
The ECM controls the charge air cooler fan operation corresponding to the engine speed, the charge air tem-
perature and the start signal. The control system has 2-step control [ON/OFF]. The ECM does not directly drive
the charge air cooler fan. It controls the ON/OFF charge air cooler fan relay, which in turn controls the charge
air cooler fan.
When the charge air temperature is above 67ÉC (153ÉF) and engine speed is more than 1,600 rpm, the charge
air cooler fan operates.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
I/C FAN RLY+When charge air cooler fan is stopped. OFF
+When charge air cooler fan operates. ON
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
8 G/ORCharge air cooler fan
relayEngine is running.
Charge air cooler fan is not operating.BATTERY VOLTAGE
(11 - 14V)
Engine is running.
Charge air cooler fan is operating.0-1V
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
EC-178
DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK OVERALL FUNCTION.
1. Turn ignition switch ``OFF''.
2. Disconnect charge air temperature sen-
sor harness connector.
3. Connect 150Wresistor to charge air
temperature sensor harness connector.
4. Start engine and keep engine speed at
2,000 rpm.
5. Make sure that charge air cooler fan
operates.
NG
cOK
INSPECTION END
CHECK POWER SUPPLY.
1. Stop engine.
2. Disconnect charge air cooler fan relay.
3. Turn ignition switch ``ON''.
4. Check voltage between terminals
V2,
V5and ground with CONSULT or
tester.
Voltage: Battery voltage
OK
cNG
Check the following.
+Harness connectors
M21,E127
+10A fuse
+15A fuse
+Fuse block
M2
+Harness for open or
short between charge air
cooler fan relay and
fuses
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect charge air cooler fan motor
harness connector.
3. Check harness continuity between relay
terminal
V3and motor terminalV1,
motor terminal
V2and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
E127,M21
+Harness connectors
M50,F5
+Harness for open or
short between charge air
cooler fan relay and
charge air cooler fan
motor
+Harness for open or
short between charge air
cooler fan motor and
engine ground
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
jA
SEF710V
SEF798V
SEF712V
SEF799V
SEF711V
.
.
.
.
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
Charge Air Cooler Fan Control (Cont'd)
EC-180
