P0128

DTC P0128: Cooling System Malfunction (2002-2005 models)

NOTE:
- If the DTCs listed below are stored at the same time as DTC P0128, troubleshoot those DTCs first, then recheck for P0128.
- Before you troubleshoot, record all freeze data and review the general troubleshooting information.

P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor
P1106,P1107, P1108(P2227, P2228, P2229)*: Barometric pressure (BARO) sensor
P1259; VTEC system
P0116, P0117, P0118 (P0125)*: Engine coolant temperature (ECT) sensor
P0112, P0113: Intake air temperature (IAT) sensor
P0335, P0336: Crankshaft position (CKP) sensor
P0300: Random misfire detected
P0301, P0302, P0303, P0304: No. 1, No. 2, No. 3 or No. 4 Cylinder misfire detected
P0505 (P0506, P0507)*: Idle control system
P1519(P0511)*: Idle air control (IAC) valve *: 2004-2005 models

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 A/C is off.
3. Check the radiator fan.

Does the radiator fan keep running?

YES - Check the radiator fan circuit, radiator fan switch circuit for open, radiator fan switch circuit for short and the radiator fan switch. If they are OK, substitute a known-good ECM and recheck. If the symptom/indication goes away, replace the original ECM.

NO - Replace the thermostat.