DTC P1486: Cooling System Malfunction (2004 3.5RL)

NOTE: DTC P1486 can set occasionally when hood is opened. If some of the DTCs listed below are stored at the same time as DTC P1486, troubleshoot those DTCs first, then troubleshoot DTC P1486:

P0107, P0108, P1128, P1129: MAP Sensor
P2227, P2228, P2229: Barometric Pressure Circuit
P1259, P1279: VTEC System
P0401: Insufficient EGR Flow
P0404 Insufficient EGR Valve Lift
P0406: EGR Valve Position Sensor High Voltage
P0125, P0116, P0117, P0118: Engine Coolant Temperature Circuit
P0112, P0113: Intake Air Temperature Circuit
P0345, P0349, P1336, P1337: Crankshaft Position Sensors 1 & 2
P0300: Random Misfire
P0301, P0302, P0303, P0304, P0305, P0306: Cylinder No. 1, 2, 3, 4, 5 or 6 Misfire Detected
P0506, P0507: Idle Control System Malfunction
P0511: Idle Air Control Valve

Turn ignition switch off. Check engine coolant level. Add coolant as necessary. If coolant level is okay, turn ignition switch ON (II). Check radiator fan. If radiator fan does not keep running, check thermostat. If radiator fan keeps running, check radiator fan circuit, radiator fan switch circuit, and radiator fan switch. Repair as necessary. If all components are okay, substitute a known-good PCM, and recheck. If symptom or indication goes away, replace original PCM.