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 (see 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.
- 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.
- Turn the ignition switch ON (II), and make sure the A/C is off.
- Check the radiator fan.
Does the radiator fan keep running?
- YES - Check the radiator fan circuit (see RADIATOR FAN CIRCUIT TROUBLESHOOTING ), radiator fan switch circuit for open (see RADIATOR FAN SWITCH CIRCUIT TROUBLESHOOTING (OPEN) ), radiator fan switch circuit for short (see RADIATOR FAN SWITCH CIRCUIT TROUBLESHOOTING (OPEN) ) and the radiator fan switch (see RADIATOR FAN SWITCH TEST ). If they are OK, substitute a known-good ECM (see HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES ) and recheck. If the symptom/indication goes away, replace the original ECM (see ECM REPLACEMENT ).
- NO - Replace the thermostat (see THERMOSTAT REPLACEMENT ).