Honda Civic Service Manual page 398

PGM-FI System
Engine Coolant Temperature (ECTI Sensor
The scan tool indicates Diagnostic Trouble code (DTC) P0116; A range/performance problem in the
Engrne
Coolant Temperature (ECT) Sensor circuit.
The ECT Sensor is a temperature dependant resistor (thermistor). The resistance of the thermistor decreases
as the engine
coolant temperature increases as shown oetow.
RESISTANCE
(ko)
NOTE: lf DTC P0117 and/or P01'18 are stored at the same time as DTC
for DTC P0116.
Possible Cause
. ECT sensor deterioration
. Malfunction in the thermostat and cooling system
Troubleshooting Flowchart
- a 3 2 6 8 r 0 a l a 0 l ? 6 2 t 2 2 4 8 1 ' r r
-20 o 20 ao o D r@ Il,
r'c)
ENGINE COOLANT IEMPERATURE
P0116, troubleshoot those DTCS first. then recheck
11 - 1 2 8
THERMISTOR
-
The MIL has bogn reported on.
-
DTC P0116 is stored.
Problem verification:
1 . S t a r t t h e e n g i n e . H o t d t h e
engine at 3,000 rpm with no
load (in Park or neutral) until
t h e r a d i a t o r f a n c o m e s o n ,
then let it idle.
2. With the scan tool, check the
Intermiftent lailure. system is OK
ai thi. time. Ch.ck the thc.mo-
stat 6nd thc cooling system.
is 176 200'F {80 - 93'C)or
0 . 0 - 0 . T V i n d i c a t e d ?
Check the thermostat and the
cooling system. ll they als OK,
raplace the ECT sensor.