( TL19E00G24100000000HAAT05 )

Insufficient heating

Diagnostic procedure

1. Check the coolant level, R20A3 engine model, K24Z3 engine model
2. Check the radiator cap; R20A3 engine model, K24Z3 engine model
3. Check the operation of the air mix control motor and door
4. Check the coolant temperature
5. Check the blower motor unit for obstructions
6. Check for air leaks around the ducts and vents
7. Check the inlet hose temperature
8. If it is COLD, check for restrictions in the hose, a damaged or leaking thermostat, and a damaged or leaking water pump.
9. If it is HOT, check for restrictions in the heater core. Back flush the heater core using standard commercially available equipment, or replace the heater core.

Also check for

- Damaged cylinder head gasket