Toyota Pick-ups, Land Cruiser, and 4 Runner 1997-00

Evaporative Emission Controls

Print

OPERATION



The evaporative emission control system prevents the release of unburned hydrocarbons from the liquid gasoline vapor into the atmosphere. Evaporative fuel vapor from the tank is routed to the charcoal canister located in the engine compartment. The charcoal canister stores the vapor until the engine coolant temperature reaches 129° F (54° C). When the engine coolant temperature is above 129° F (54° C) and the throttle is open, a vacuum switching valve opens to allow vapors trapped in the canister to enter the intake manifold.

A fuel filler cap with a check valve allows air to enter the fuel tank as the fuel is used. This prevents a vacuum build-up in the fuel tank as the engine is running.

COMPONENT TESTING



Charcoal Canister

There were two type of charcoal canisters installed on these Toyota trucks. On early model vehicles, the canister only has one or two vacuum hoses. Later model vehicles have canisters with multiple vacuum lines and hoses attached. Regardless of which type your vehicle has, it's always a good idea to tag any vacuum lines before disconnecting them.

EARLY MODEL CANISTERS
  1. Label and disconnect the vacuum hose at the top of the canister. Remove the charcoal canister from the vehicle.
  2.  
  3. Remove the vacuum switching valve.
  4.  



Click image to see an enlarged view

Fig. Always label hoses and wires prior to removalearly model charcoal canister shown



Click image to see an enlarged view

Fig. The hoses are easily removed by sliding the clamp off the port end

  1. Look for cracks or damage to the outside of the canister.
  2.  
  3. Using low pressure compressed air ( 1 / 2 1 psi), blow into the tank pipe and check that air flows without any resistance from the other pipes.
  4.  
  5. Blow air into the purge pipe and check that air does not flow from the tank pipe and that it will flow, without resistance, from the other pipe. If there is any problems found, replace the canister.
  6.  

Do NOT attempt to wash the canister. No activated carbon should come out of the canister while cleaning or inspecting the unit. If it does, replace the canister.

  1. Install the canister on the vehicle and reconnect the hoses.
  2.  

LATE MODEL CANISTERS
  1. Label and disconnect the vacuum hoses at the top of the canister. Remove the charcoal canister from the vehicle.
  2.  
  3. Remove the vacuum switching valve.
  4.  
  5. Look for cracks or damage to the outside of the canister.
  6.  
  7. Install plugs onto ports A and B .
  8.  



Click image to see an enlarged view

Fig. Typical locations of the ports and plugs3RZ-FE engine shown, 2RZ-FE and 5VZ-FE similar



Click image to see an enlarged view

Fig. Blow air into port D and check that air does not flow from port F



Click image to see an enlarged view

Fig. Apply vacuum to port C



Click image to see an enlarged view

Fig. You can use your finger to plug port C



Click image to see an enlarged view

Fig. Charcoal canister port identification2UZ-FE engine

  1. While holding port C closed, blow air (about 1 / 4 psi into port D and check that air does not flow from port F .
  2.  
  3. Apply vacuum (about 1 in. Hg to port C , check that the vacuum does not decrease when port F is released.
  4.  
  5. While holding port F closed, apply about 1 in. Hg to port D . Check that the vacuum does not decrease when port C is closed, and check that the vacuum decreases when port C is released. If a problem occurs, replace the charcoal canister.
  6.  
  7. Remove the plugs.
  8.  
  9. Reinstall the canister.
  10.  

 
label.common.footer.alt.autozoneLogo