P0446 Evaporative Emission Control System Vent Control Circuit
The ECT PWR green light came on along with the eng service symbol. Took the 1999 toyota four runner to emissions inspection and this code was what failed the vehicle. What can I do to fix this problem instead of taking vehicle to dealer. No warranty
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Re: P0446 Evaporative Emission Control System Vent...
ECT stands for engine coolant temperature. So I would start by making sure that your engine coolant system is not leaking and is full of coolant.If you want to tackle the job yourself you could purchase Haynes techbook # 10206 OBD -2 and electronic engine management systems or check your local library they may have a copy and they have troubleshooting steps you can do with a scan tool or multimeter. Good luck and hopefully this helps you a little.
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P0446 Evaporative Emission Control System Vent Control Circuit Malfunction. The code P0446 is set when the engine computer recognizes a fault or restriction at the vent control part of the Evaporative emission control system (EVAP).
Specifically, P0446 indicates an Evaporative Emission Control (EVAP) system vent control circuit malfunction. Typically, this indicates a faulty vent valve, a bad control circuit for that valve, or a blockage in the vent valve. In all cases, it clearly shows the mechanic that a check of the EVAP vent valve is in order.
When your Toyota's P0441 is triggered, it usually indicates a bad vacuum switch or a leak in the EVAP system that is preventing fuel vapors from reaching the canister. The P0441 code can also indicate a faulty or "stuck" PCV, a short circuit in the feed circuit, or a faulty purge solenoid.
P0446 Evaporative Emission Control System Vent Control Circuit Malfunction
The code P0446 is set when the engine computer recognizes a fault or restriction at the vent control part of the Evaporative emission control system (EVAP). The description of the fault varies between different car manufacturers, but one thing is common, the code P0446 doesn't directly point to a defective part; some testing might be required to pinpoint the faulty component.
What can cause the code P0446:
- faulty vent control valve
- blockage at the vent hose, vent filter or vent control valve
- open or short in the vent control valve circuit
- bad charcoal canister
- EVAP system leak
- faulty EVAP system pressure sensor
- bad vacuum switching valve (VSV)
- stuck open purge valve (solenoid)
NOPE CANT ERASE CODES UNTIL THE PROBLEM IS FIXED OR THE SERVICE ENGINE LIGHT SOON WILL STAY ON. CODE PO441 - EVAPORATIVE EMISSION EVAP SYSTEM INCORRECT FLOW DETECTED.CHECK INTAKE VACUUM HOSE CONNECTIONS AT THE EVAP CANISTER PURGE VALVE.IF ALL IS GOOD.THE EVAP CANISTER PURGE VALVE COULD BE BAD. CODE PO 442 - EVAPORATIVE EMISSION EVAP SYSTEM SMALL LEAK DETECTED. EVAPORATIVE EMISSION SYSTEM LARGE LEAK DETECTED FUEL CAP LOOSE OR OFF MISSING. CODE PO 446 - EVAPORATIVE EMISSION EVAP SYSTEM VENT CONTROL CIRCUIT MALFUNCTION.
P0446 - Evaporative Emmission Control System Vent Control Circuit
Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Batt. voltage with key on. The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test.
Causes: A code P0446 could mean one or more of the following has happened: * Faulty vent valve * Open, short or excessive resistance on Vent valve control circuit * Blockage of vent valve * Bad PCM
Possible Solutions: With a P0446 OBD-II trouble code, here are some things to try: * Replace Vent valve * Repair open, short, or resistance problem in control circuit * Repair open, or short, or resistance problem in power circuit * Replace PCM
That is a problem in the evaporative emission control system.
Could be anything causing it
Clogged filter in the charcoal canister
A leak in one of the vacuum lines
The purge valve not working,,,etc.
The best thing is to take it and have it checked out, they might have to do a smoke test to find the problem.
All they do is inject smoke into the system, if there is a leak the smoke will come out of it. All it takes is a pin hole in these emission systems to screw it all up.
P0446 Evaporative Emission System Vent Control Circuit.
The following are descriptions of all Evaporative possible codes:
P0441 Evaporative Emission System Incorrect Purge Flow P0442 Evaporative Emission System Leak Detected (small leak) P0443 Evaporative Emission System Purge Control Valve Circuit P0444 Evaporative Emission System Purge Control Valve Circuit Open P0445 Evaporative Emission System Purge Control Valve Circuit Shorted P0446 Evaporative Emission System Vent Control Circuit P0447 Evaporative Emission System Vent Control Circuit Open P0448 Evaporative Emission System Vent Control Circuit Shorted P0449 Evaporative Emission System Vent Valve/Solenoid Circuit P0450 Evaporative Emission System Pressure Sensor/Switch P0451 Evaporative Emission System Pressure Sensor/Switch Range/Performance P0452 Evaporative Emission System Pressure Sensor/Switch Low P0453 Evaporative Emission System Pressure Sensor/Switch High P0454 Evaporative Emission System Pressure Sensor/Switch Intermittent P0455 Evaporative Emission System Leak Detected (large leak) P0456 Evaporative Emission System Leak Detected (very small leak) P0457 Evaporative Emission System Leak Detected (fuel cap loose/off) P0458 Evaporative Emission System Purge Control Valve Circuit Low P0459 Evaporative Emission System Purge Control Valve Circuit High
At least the cap isn't loose for the gas tank.
I would clear the code with an OBD-II Scanner 'erase code' button, and see how long it takes for it to come back.