Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 494

Code No. 21 Engine coolant temperature sensor system
Range of Check
Ignition switch: ON
Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.
Set conditions
Sensor output voltage is 4.6 V or more (corresponding to an engine coolant
temperature of –45_C or less) for 4 seconds.
or
Sensor output voltage is 0.1 V or less (corresponding to an engine coolant
temperature of 140_C or more) for 4 seconds.
Range of Check
Ignition switch: ON
Engine speed is approx. 50 r/min or more
Set conditions
The sensor output voltage increases from 1.6 V or less (corresponding to an
engine coolant temperature of 40_C or more) to 1.6 V or more (corresponding
to an engine coolant temperature of 40_C or less).
After this, the sensor output voltage is 1.6 V or more for 5 minutes.
Check the engine coolant temperature
sensor. (Refer to P.13B-71.)
OK
Measure at the engine coolant tem-
perature sensor connector A-76.
Disconnect the connector, and
measure at the harness side.
Voltage between 1 and earth
(Ignition switch: ON)
OK: 4.5 – 4.9 V
Continuity between 2 and earth
OK: Continuity
OK
Check the following connector:
A-76
NG
Repair
MPI –
Troubleshooting
NG
Replace
NG
Check the following connector:
B-31
Check trouble symptom.
Check the harness wire between the
engine-ECU and the engine coolant
temperature sensor connector.
Replace the engine-ECU.
OK
Check trouble symptom.
Replace the engine-ECU.
Probable cause
Malfunction of the engine coolant temperature sensor
Improper
short-circuited harness wire of the engine coolant
temperature sensor circuit
Malfunction of the engine-ECU
NG
Repair
OK
NG
NG
Repair
OK
NG
13B-13
connector contact, open circuit or