Autopapyrus · Lexus LX 5.7 V8 (3UR-FE) (2012)
https://autopapyrus.com/guides/lexus/lx/evap-canister-diagnosis-and-service/
https://autopapyrus.com/guides/lexus/lx/evap-canister-diagnosis-and-service/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.
Lexus LX 5.7 V8 (3UR-FE) (2012): EVAP Canister Diagnosis and Service
The canister traps gasoline vapors from the fuel tank and releases them into the engine through the purge valve. The fault is usually caused not by the charcoal granules themselves, but by the valves, hoses, or a clogged vent line. Typical symptoms: EVAP codes (P0441, P0446, P0455, P0456), a gasoline smell, difficult refueling with the pump nozzle constantly shutting off, and an unstable idle after refueling. The exact canister removal procedure for this generation is not documented in public service materials, so below is the general principle based on the typical layout.
Part
- 🔩 EVAP canister (charcoal fuel vapor canister) assembly, canister purge valve (VSV solenoid valve), vent valve with EVAP system pressure sensor. It is best to match the exact part numbers for your trim to your VIN to avoid ordering the wrong part
Step by step
10 steps- Read the trouble codes with a scan tool and save them. If the codes are only for system leaks (P0455, P0456), first check the fuel filler cap: the seal, the latching, and any cracks. This is the most common cause.
- Inspect the purge valve in the engine bay. Disconnect the electrical connector and check the coil resistance with a multimeter (check the range for this valve against the service manual). Apply 12 V from the battery to the valve: it should click, and air should flow through only while power is applied. If air passes through without power, the valve is stuck open and must be replaced.
- Inspect the vacuum and vapor lines from the valve to the canister and to the intake. On older vehicles the rubber sections crack, and the plastic quick-connect fittings break. Replace any damaged sections.
- Shut off the engine and let it cool. Disconnect the negative battery terminal. Gasoline vapors are flammable, so work away from sparks and open flames.
- Raise the rear of the vehicle on a lift, or on a jack with jack stands. The canister is located at the rear of the underbody next to the fuel tank, usually under a shield or cover. Remove the shield if one is fitted.
- Locate the vent valve and pressure sensor assembly on the canister. Disconnect the connector. Check the fitting for clogging with dirt, spider webs, or water. The vent line often gets clogged on vehicles driven on dirt roads or after water crossings.
- Disconnect the lines from the canister by pressing the quick-connect retainers. Label the lines or photograph their positions. Remove the mounting hardware and carefully lower the canister. Installation torque: the fasteners are small, so tighten them moderately, about 5-10 N·m (4-7 lb-ft), or per the service manual.
- Blow-test the housing. Apply light air pressure (up to 1-2 bar (15-29 psi)) to the vent fitting and make sure it passes through to the purge fitting and to the tank, and that vapors exit freely at the tank fitting. Excessive pressure can damage the housing and valves.
- If you can hear the granules rattling inside the canister, it is soaked with gasoline, liquid is leaking out of it, or air does not pass through, cleaning will not help. Never wash the charcoal with water, soap, or solvents: wet charcoal loses its properties, and a canister flooded with gasoline is saturated and must be replaced. Disassembling the housing and "baking out" the charcoal is also not recommended, because the housing is usually a sealed, non-serviceable unit.
- Reinstall the canister, connect all the lines (the retainers must click), the connectors, and the shield. Reconnect the battery, clear the codes, and take a 10-20 minute drive with varied driving conditions. Check that the code has not returned. If the EVAP test did not complete or pass, check the lines and the fuel cap for leaks.
Common mistakes and warnings
- Working on the fuel system is a fire hazard: do not smoke, do not work near sources of sparks, and ensure ventilation. If fuel is leaking from the canister or lines, do not start the engine until you have fixed the cause. If you lack experience working under the vehicle and with fuel lines, have a repair shop do the job. Do not defeat the EVAP system with "bypass" devices and do not remove the canister: this will cause trouble codes and a gasoline smell, and on some vehicles it also causes fuel tank pressure problems.