CUSTOMER CONCERN The check-engine light is on with DTC P012800 indicating that engine coolant temperature remains below the thermostat's specified operating range. CAUSE The engine coolant thermostat failed and did not regulate coolant temperature to the specified range. CORRECTION Remove and replace the engine coolant thermostat, clear DTC P012800, and verify coolant temperature reaches and maintains the specified operating range.

CUSTOMER CONCERN Check-engine light is on with DTC P1116. CAUSE Testing confirmed the coolant heat-storage water pump failed to circulate coolant. CORRECTION Remove and replace the failed coolant heat-storage water pump. Refill and bleed the cooling system.

CUSTOMER CONCERN Cabin heater does not produce warm air, and DTCs P1116, P1121 and P1122 are stored. CAUSE Testing confirmed the coolant flow-control valve failed to route coolant correctly. CORRECTION Remove and replace the failed coolant flow-control valve. Refill and bleed the cooling system.

CUSTOMER CONCERN The hybrid warning light is on with inverter-cooling DTC P0A93-346 stored. CAUSE The inverter coolant reservoir was full, but active testing confirmed that the inverter water pump was not circulating coolant. CORRECTION Remove and replace the inverter water pump. Refill and bleed the inverter cooling circuit.

CUSTOMER CONCERN The vehicle intermittently enters limp mode with DTCs P0A7C, P1A0D, P1A0E, and P1A0F stored. CAUSE The confirmed failure is the Motor Electronics Cooling System pump, which is not circulating coolant through the hybrid electronics cooling circuit. CORRECTION Remove and replace the Motor Electronics Cooling System pump.

CUSTOMER CONCERN Customer states there is no heat inside the vehicle. DTCs P1116, P1121 and P1122 are stored. CAUSE Active testing showed the coolant heat-storage water-valve position signal did not follow commanded positions, confirming a failed coolant flow-control valve. CORRECTION Remove and replace coolant flow-control valve. Refill and bleed engine cooling system, clear DTCs and verify cabin heat operation.

CUSTOMER CONCERN Customer states a noise begins in the engine compartment as soon as the vehicle is powered on. CAUSE Inspection isolated the noise to the auxiliary heater water pump, one of the components operating immediately at power-up. CORRECTION Remove and replace auxiliary heater water pump. Refill and bleed the heater-coolant circuit and verify quiet pump operation.

CUSTOMER CONCERN Customer states the malfunction indicator light is on. DTC P0A93 is stored, and the inverter water pump runs briefly before shutting off when commanded with a scan tool. CAUSE The pump retained battery voltage and ground but would not continue operating, confirming an internally failed inverter water pump. CORRECTION Remove and replace inverter water pump. Refill and bleed inverter cooling circuit, clear DTC P0A93 and verify commanded pump operation.

CUSTOMER CONCERN Customer states the malfunction indicator light is on with DTCs P0A93 and P0AC4, and the vehicle will not complete its emissions test. CAUSE The inverter cooling reservoir was empty, and inspection confirmed coolant leaking from an inverter cooling-system hose. CORRECTION Repair leaking inverter cooling-system hose. Refill and bleed inverter cooling circuit, clear DTCs P0A93 and P0AC4 and verify coolant circulation.

CUSTOMER CONCERN Customer states the engine-temperature reading fluctuates while driving and DTC P0117 returns after coolant-temperature sensor replacement. CAUSE The 5-volt reference and warmed-up sensor signal tested correctly, confirming the radiator was not maintaining stable coolant temperature. CORRECTION Remove and replace radiator. Refill and bleed engine cooling system, clear DTC P0117 and verify stable coolant temperature.

CUSTOMER CONCERN Customer states the engine overheats while driving and the heater blows cold. Coolant temperature reaches approximately 230°F with the cooling fans operating. CAUSE Cooling-system bleeding and flow checks confirmed combustion leakage from a failed cylinder-head gasket. CORRECTION Remove and replace failed cylinder-head gasket. Refill and bleed engine cooling system and verify normal operating temperature.

CUSTOMER CONCERN Customer states the engine overheats and coolant leaks from the radiator area. CAUSE Inspection identified the larger radiator nearest the engine as the leaking engine-cooling radiator. CORRECTION Remove and replace engine radiator. Refill and bleed engine cooling system and verify no coolant leaks.

CUSTOMER CONCERN Customer states the check-engine light is on and DTC P0128 is stored. CAUSE Cold-soak temperature data and cooling-system checks confirmed the engine coolant thermostat was not maintaining the specified regulating temperature. CORRECTION Remove and replace engine coolant thermostat. Refill and bleed engine cooling system. Clear DTC P0128.

CUSTOMER CONCERN Customer states DTC P1116 appeared two weeks after the cooling system was drained and refilled. CAUSE Air remained trapped in the coolant heat-storage circuit; this system requires scan-tool-assisted bleeding. CORRECTION Perform cooling-system air-bleed procedure with a compatible scan tool and clear DTC P1116.

CUSTOMER CONCERN Customer states there is no cabin heat and DTCs P1116, P1121 and P1122 are stored. CAUSE Active testing of the coolant heat-storage system confirmed the coolant flow-control valve position did not track commanded positions. CORRECTION Remove and replace coolant flow-control valve. Refill and bleed engine cooling system.

CUSTOMER CONCERN Customer states the hybrid warning is on and DTC P0A93 is stored. CAUSE The inverter cooling-water pump failed to circulate coolant through the inverter cooling system. CORRECTION Remove and replace inverter water pump. Refill and bleed inverter cooling circuit.

CUSTOMER CONCERN Customer states the check-engine light is on with DTC P0128. CAUSE Cold-soak temperature comparison confirmed the engine coolant thermostat was not regulating temperature correctly. CORRECTION Remove and replace engine coolant thermostat. Refill and bleed engine cooling system.

CUSTOMER CONCERN The check-engine light was on with DTC P0128. CAUSE The engine coolant thermostat was not regulating coolant temperature correctly, so the engine did not reach the expected temperature. CORRECTION The engine coolant thermostat was replaced.

CUSTOMER CONCERN The check-engine light was on with DTC P0128. CAUSE The engine coolant thermostat was not maintaining the expected regulating temperature. CORRECTION The engine coolant thermostat was replaced.