P401 Insufficient EGR flow-Clean out the EGR and test it
P0171/P0174-A lean fuel condition can be caused by:
* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge to check fuel pressure at idle)
* Dirty fuel injectors. (Try cleaning the injectors)
* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)
* Leaky EGR valve. (Check operation of EGR valve)
* Leaky PCV Valve or hose. (Check valve and hose connections)
* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)
P1450, Inability of Evaporative Emission Control System to bleed fuel tank
Possible causes:
EVAP canister purge outlet tube (EVAP canister purge valve to EVAP canister) blockages or kinks.
EVAP canister tube (fuel tank to EVAP canister) blockages or kinks.
Fuel vapor elbow on EVAP canister contaminated.
Restricted EVAP canister.
Canister vent (CV) solenoid stuck closed (partially or fully).
Plugged or contaminated CV solenoid filter.
EVAP canister purge valve stuck open.
Fuel filler cap stuck closed (no vacuum relief).
VREF circuit open in fuel tank pressure (FTP) sensor.
Damaged FTP sensor. (Fuel tank pressure)
Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).
Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.
Check CV solenoid filter for blockage or contamination.
The common things I've seen are mud in the canister and the canister vent solenoid being shot or the wiring to the canister vent solenoid being torn off. The resistance of the solenoid should be 48-65 ohms.
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Wednesday, January 21st, 2009 AT 3:40 PM
