Cooling System Malfunction - Honda Civic 2002-2003 Service Manual

PGM-FI System
OTC Troubleshooting (cont'd)
Ole P0128: Cooling System Malfunction
NOTE: If the DTCs listed below are stored at the same
time as DTC P0128, troubleshoot those DTCs first, then
recheck for P0128.
P0107, P0108, Pl128, Pl129: Manifold absolute
pressure (MAP) sensor
Pll06, Pll07, Pll08: Barometric pressure (BARO)
sensor
P1259: VTEC system
POl16, POl17, P0118: Engine coolant temperature (ECT)
sensor
POl12, POl13: Intake air temperature (IAT) sensor
P0500: Vehicle speed sensor (VSS)
P0335, P0336: Crankshaft position (CKP) sensor
P0300: Random misfire
P0301, P0302, P0303, P0304: No.1, No.2, No.3 or No.4
cylinder misfire
P0505: Idle control system malfunction
P1519: Idle air control (lAC) valve
DTC P0128 can occasionally set when the hood is
opened while the engine is running.
1. Check the engine coolant level.
Is the engine coolant level low?
YES-Refill the engine coolant. If necessary, repair
the coolant leakage .•
NO-Go to step 2.
2. Turn the ignition switch ON (II), and make sure the
NC is off.
11-64
3. Check the radiator fan.
Does the radiator fan keep running?
YES-Check the radiator 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. If the Circuits, the switch, and the
connections are OK, update the ECM if it does not
have the latest software, or substitute a known-
good ECM, then recheck (see page 11-6). If the
symptom/indication goes away with a known-good
ECM, replace the original ECM .•
NO-Replace the thermostat (see page 10-8) .•
•