EXHAUST HEAT RECIRCULATION SYSTEM ON-VEHICLE INSPECTION

CAUTION / NOTICE / HINT

PROCEDURE

1. INSPECT FRONT EXHAUST PIPE ASSEMBLY (TWC: Rear Catalyst)

   CAUTION:

   To prevent burns, do not touch the engine, exhaust pipe or other high temperature components while the engine is hot.

   
   

   1. Inspect the exhaust flow control valve operation.

      
      
      1. 

         *a	Protective Tape

         Using a screwdriver, move the exhaust flow control valve from the bottom of the vehicle. Check that the valve moves smoothly.

         OK
         Valve moves smoothly.

         If the valve is stuck or does not move smoothly, replace the front exhaust pipe assembly (TWC: Rear Catalyst).

         Click here

   2. Inspect the exhaust pipe gas control actuator sub-assembly.

      
      

      1. Connect the GTS to the DLC3.

      2. Turn the power switch on (IG).

      3. Turn the GTS on.

      4. Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.

         
         Powertrain > Engine > Data List

         Tester Display
         Coolant Temperature

      5. 

         While checking the engine coolant temperature with the GTS, check the operation of the exhaust pipe gas control actuator rod when the temperature rises.

         Standard
         Condition Rod Operation Cold (below approximately 71°C (160°F)) → Warmed up (approximately 80°C (176°F) or higher) Rod gradually extends smoothly as the temperature rises

         If the exhaust pipe gas control actuator rod does not extend smoothly, replace the exhaust pipe gas control actuator sub-assembly.

         Click here

         Tech Tips

         
         

         • After the engine has warmed up (the thermostat temperature is approximately 80°C (176°F) or higher), the rod should be extended approximately 7.2 mm (0.283 in.) or more compared to when the engine is cold (the thermostat temperature is below approximately 71°C (160°F)).

         • The coolant temperature shown in the Data List may slightly deviate from the thermostat temperature. This is because the Data List value indicates the temperature detected by the engine coolant temperature sensor, which is mounted on the engine, while the thermostat is positioned in the exhaust pipe gas control actuator sub-assembly.

         • If it is difficult to check while the rod is operating, allow the engine to cool down until the coolant temperature matches the ambient temperature and then check the rod operation again.

      6. Check for any cracks or damage on the exhaust pipe gas control actuator rod.

         OK
         No cracks or damage is found.

         If any cracks or damage is found, replace the front exhaust pipe assembly (TWC: Rear Catalyst).

         Click here

2. INSPECT FOR ENGINE COOLANT LEAK FROM FRONT EXHAUST PIPE ASSEMBLY (TWC: Rear Catalyst)

   CAUTION:

   Do not remove the reserve tank cap and air release valve while the engine or radiator assembly are still hot. Pressurized, hot engine coolant and steam may be released and cause serious burns.

   Note

   Before performing this inspection, turn the A/C switch off.

   
   

   1. Turn the power switch off. Check for engine coolant leaks from the front exhaust pipe assembly (TWC: Rear Catalyst) and the heater water hose around the engine coolant temperature sensor.

   2. Remove the reserve tank cap.

   3. Add engine coolant to the FULL line of the radiator reserve tank assembly.

   4. 

      *a	Radiator Cap Tester

      Install a radiator cap tester.

   5. Put the engine in inspection mode (maintenance mode).

      Click here

   6. Warm up the engine.

   7. Pump the radiator cap tester to 122 kPa (1.2 kgf/cm², 17 psi), and then check that the pressure does not drop.

      If the pressure drops, check the front exhaust pipe assembly (TWC: Rear Catalyst) and the heater water hose around the engine coolant temperature sensor for leaks.

   8. Remove the radiator cap tester.

   9. Install the reserve tank cap.