Help, P420 03 corrola

[beck5012]

daily,,no matter what..have put on New cap,,one click,,two or more,,same thing..have a echo 2000 doing same thing all the time..i can clear code and soon as a few miles,,or under hard ecelleration,,p420..with the echo,,if it warms up too fast it comes on also..even run with loose cap and same thing..is this normal??

[invader]

P0420: Catalyst System Efficiency Below Threshold. The code comes up if the downstream O2 sensor signal is not different enough from the upstream O2 sensor. It can be caused by a bad catalytic converter, exhaust leak, weak O2 sensor...

[invader]

You may need to have the ECM recalibrated and replace the catalytic converter.

TSB EG028–04: http://www.carsforum.co.il/vb/attach...entid=152813&d

[beck5012]

sorry but it is a 440 on both cars,,n with the echo,,it seems if it like warms up to fast on a cooler day like 70 out it comes on right away..but if warmed up on a hotter day it dont come on as much...or not at all..does this make any cents??

[invader]

Corolla instead of Corrola, and code P0440 instead of P0420 makes sense instead of cents...
It sounds like a evaporative system leak concern, possibly faulty Vent solenoid or VSV. Or maybe Leaking Evap hose around Canister area. Your best bet is to have your evap system smoke tested before replacing parts, with enhanced scanner that can close evap solenoid.

OBD Leak Test:
- The test is based on applying a vacuum to the system and monitoring the vacuum over time.
- The ECM (computer) monitors the vacuum level through a Fuel Tank Sensor.
- After some time, the EVAP canister purge valve/solenoid & EVAP vent valve/solenoid are turned ON, allowing the engine vacuum to draw a small vacuum on the entire evaporative emission system.
- If a sufficient vacuum level cannot be achieved, or decreases too fast, a "large leak" or faulty purge valve/solenoid is detected and could set the P0440 code.

This can be caused by any of the following conditions:
- Leaking fuel tank or fuel filler neck.
- Leaking fuel sender assembly O-ring.
- Disconnected or faulty fuel tank pressure sensor.
- Missing, not completely installed or faulty fuel fill cap.
- Disconnected, damaged, pinched, or blocked purge line.
- Disconnected or damaged EVAP vent hose.
- Disconnected, damaged, pinched, or blocked fuel tank vapor line.
- Disconnected or faulty canister purge valve/solenoid.
- Disconnected or malfunctioning vent valve/solenoid.
- Open ignition feed circuit to the vent or purge valve/solenoid.
- Damaged EVAP canister.
Conditions for the test to run (by the control system):
- Certain DTCs are NOT set (from TP sensor, IAT sensor, or MAP sensors)
- System voltage is between 10 & 16 volts.
- Fuel tank fuel level is between 15% & 85%.
- The barometric Pressure (BARO) is more than 75 kPa.
- The Intake Air Temperature (IAT) is between 40°F and 86°F.
- The Engine Coolant Temperature (ECT) is between 40°F & 86°F.
- The startup IAT & ECT are within 16°F of each other.

Clearing the code or turning OFF the Malfunction Indicator Lamp (MIL):
- The code will clear if the fill cap is tightened or reinstalled.
- This DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.
- The PCM will turn the MIL OFF when the diagnostic has been run & the fault condition is no longer present.
- A "history" DTC P0440 will clear after 40 consecutive warm-up cycles have occurred without a fault.

Notes:
- The control module will illuminate the Malfunction Indicator Lamp (MIL) during the 2nd consecutive trip in which the diagnostic is run and fails.
- The system will store conditions present when the DTC set as Freeze Frame/Failure Records data.