Remove the radiator cap in two steps. First turn the cap counterclockwise to the first stop. Then push and turn it further in the same direction and remove the cap.

NOTE
Wet the cap sealing surfaces with water or coolant to prevent pressure leaks.

NOTICE
During pressure testing, do not exceed the pressure for which the system is designed. The maximum pressure is 142 kPa (1.45 kgf/cm², 21 psi).
If the pressure holds steady, the system is all right.
If the pressure drops and no external source is found, check for internal leaks. Droplets in the engine oil indicate internal leakage. Check the cylinder head gasket and the water pump.
Remove the pressure tester, replenish the coolant, and install the radiator cap.
Coolant Deterioration Inspection
Cooling System FlushingThermostat Removal
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Throttle Body Assy (see Throttle Body Assy Removal in
the Fuel System (DFI) chapter)
Throttle Body Assy Holder Clamp [A]
...
Front Wheel Rotation Sensor Wiring Inspection (Service Code b 43)
Disconnect the front wheel rotation sensor lead connector
[A] (see Front Wheel Rotation Sensor Removal in the
Brakes chapter).
Disconnect the KIBS hydraulic unit lead connector (see
KIBS Hydraulic Unit Removal in the Brakes chapter).
Check the wiring continuity of the W lead and ...
Coolant Reserve Tank Installation
Install the following to the coolant reserve tank [A].
Pad [B]
Gasket [C]
Cap [D]
Collar [E]
Install the coolant reserve tank and tighten the bolt [F].
Run the hoses correctly (see Cable,Wire, and Hose Routing
section in the Appendix chapter).
Fill the coolant reserve tank with ...