tacoma error p0440, 441 & 446

my truck shows check engine when i drive it cold but after i reset the battery , start and warm it up for few minutes i dont get the error codes

1. it says evaporative emmision control system malfunction for the p0440

2. EECS incorrect purge flow for p0441

3. EECS Vent Control Circuit malfunction for p0446


i have 3 error codes and i dont know where to start ?

any idea? or have someone encountered this errors before?

thnks :confused:

From the FAQ thread:
P0440
The fuel tank pressure is atmospheric pressure after the vehicle is driven for 20 min (2 trip detection logic).

Possible Problems
Fuel tank cap incorrectly installed <= Most common
Fuel tank cap cracked or damaged (Toyota part only)
Bad vapor pressure sensor/circuit
Vacuum hose cracked, holed, blocked, damaged or disconnected
Hose or tube cracked, holed, damaged, or loose
Fuel tank/filler neck cracked, holed, or damaged
Charcoal canister cracked, holed, or damaged (collision)

In above description, check hoses between vapor pressur sensor and VSV for vapor pressure sensor and charcoal canister. Also, hose between charcoal canister and fuel tank.


P0441 and/or P0446

Possible Problems
Open or short in VSV circuit for vapor pressure sensor
VSV for vapor pressure sensor
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
Open or short in VSV circuit for EVAP
VSV for EVAP
Vacuum hose cracks, hole, blocked, damaged or disconnected
Charcoal canister cracks, hole, or damaged

(P0446 is not normally associated with a loose or non-sealing gas cap. A loose or non-sealing gas cap triggers P0440)

1. Check the VSV connector for EVAP, VSV connector for vapor pressure sensor and vapor pressure sensor connector for looseness and disconnection

2. Check the vacuum hose between intake manifold and VSV for EVAP, VSV for EVAP and charcoal canister, charcoal canister and VSV for vapor pressure sensor, and VSV for vapor pressure sensor and vapor pressure sensor. Check these hoses for correct connection, looseness, cracks, holes, damage, and blockage.

3. Check voltage between terminals VC and E2 of ECM connector (4.5-5.5 V). (replace ECM if faulty)

4. Check voltages between terminals PTNK and E2 of ECM connector while applying vacuum to vapor pressure sensor (2.9-3.7 V).

If faulty, check for open and short in harness and connector between vapor pressure sensor and ECM. If ok at this point, replace vapor pressure sensor.

If voltage above is ok, Check VSV for EVAP. When ECM terminal EVP is grounded (ignition "ON"), Air should flow in pipe E (inboard on tube) on VSV and out F (outboard on tube) on VSV (Don't use high pressure air for this test). When EVP is not grounded, air does not flow in E and out F.

5. Check operation of VSV for EVAP. Remove VSV from engine. Check that there is continuity between the two terminals (30-34 ohms). If there is no continuity, replace VSV for EVAP.

Check that there is no continuity between either terminal and body. If there is continuity, replace VSV for EVAP.

Check that air does not flow from inner port (E) to outboard port (F).

Check that air flows from port E to F when you apply battery voltage across terminals. If no air flows, replace VSV for EVAP.

6. Check the vacuum hose between intake manifold and VSV for EVAP, and VSV for EVAP and charcoal canister. Check as above.

7. Check for open or short in harness and connector between EFI main-relay and VSV for EVAP and ECM. If faulty, repair or replace harness or connector. If ok, check and replace ECM.

8. Check VSV for vapor pressure sensor. When ECM terminal TPC is grounded (ignition "ON"), Air should flow in pipe E (inboard on tube) on VSV and out F (outboard on tube) on VSV. When TPC is not grounded, air flows out G (outside of connector).

If ok, check and replace charcoal canister.

If not functioning correctly, check function of VSV for vapor pressure sensor. Remove from engine.
Check that there is continuity between the terminals (33-39 ohms). Replace the VSV if there is no continuity.

Check that air flows from port E (inboard in tube) to port G (side of connector).

Check that air flows from port E to port F (outboard in tube) when battery voltage is applied across terminals. Replace VSV if function is incorrect.

9. If good, Check the vacuum hose between charcoal canister and VSV for vapor pressure sensor, and vapor pressure sensor and VSV for vapor pressure sensor - check as above.

11. Check for open and short in harness and connector between EFI main replay and VSV for vapor pressure sensor and ECM.