Dtc P0128: Cooling System Malfunction - Honda EP3 Service Manual

PGM-FI System
a
DTG Troubleshootang (cont'dl
DTC P0128: Cooling System Malfunction
NOTE; lf the DTCS listed below are stored at the same
time as DTC P0128. troubleshoot those DTCS first, then
recheck for P0128.
P 0 1 0 7 , P 0 1 0 8 , P 1 1 2 8 , P 1 1 2 9 : N 4 a n i f o l d a b s o l u t e
pressure (MAP) sensor
P] I06, P1 107, P1 108: Barometric pressure (BARO)
sensor
P1259: VTEC system
P01 16, P01 17, P01 18: Engine coolant temperature (ECT)
sensor
P01 12, P01 13: Intake air temperature (lAT) sensor
P0500: Vehicle speed sensor {VSS)
P0335, P0336: Crankshaft position (CKP) sensor
P0300: Random misfire
P 0 3 0 1 , P 0 3 0 2 , P 0 3 0 3 , P 0 3 0 4 : N o . 1 , N o . 2 , N o . 3 o r N o . 4
cylinder misfire
P0505: ldle control system malfunction
P 1 5 1 9 : l d l e a i r c o n t r o l ( l A C ) v a l v e
DTC P0128 can occasionally set when the hood is
o p e n e d w h i l e t h e e n g i n e i s r u n n i n g .
1. Check the engine coolant level
Is the engine coolant level low?
VES Refill the engine coolant. lf necessary, repair
t h e c o o l a n t l e a k a g e . l
NO Go to step 2.
2 . T u r n t h e i g n i t i o n s w i t c h O N ( l l ) , a n d m a k e s u r e t h e
A,/C is off.
11-64
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3. Check the radiator fan.
Does the tadiator fan keep running?
YES Checkthe rad iato r fan circuit (see page 10-
14), the radiator fan switch circuit (Short) (see page
10-'16), and the radiator fan switch (see page 10-17).
Also, inspect the ECT and IAT circuits and terminal
connections. lf the circuits, the switch, and the
connections are OK, update the ECI\4 if it does not
have the latest software. or substitute a known-
good ECM, then recheck (see page 1 1-6). lf the
symptom/indication goes away with a known-good
E C M , r e p l a c e t h e o r i g i n a l E C M . I
NO Replace the thermostat (see page 10-8).1