CEL again, 1996 Maxima

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Hey everyone,
if you noticed a few threads down I posted that the CEL went out while driving. It stayed out for about 500 miles or so, and the gas milage seemed better. Well now it is back on and I used the scan tool, which gave me PO440 and PO446. They both deal with the evap system (gas). Any ideas what the heck is going on? Any ideas how to fix this?


Thanks,
Zack
 
0903 (PO446)
Diagnostic Trouble Code 0903 indicates a problem with the Evaporative Emission (EVAP) Canister Vent Control Valve or its associated electric circuit.

This part is used by the Engine Control Module to perform the fuel system leak test. Since it is used only for self-diagnosis your engine will run perfectly well despite the dashboard Malfunction Indicator Lamp.

The EVAP canister and this valve are located under the car, near the rear left tire. You might check to make sure all the electrical connectors in that area are secure.

There's no telling how expensive the repair will be, because no definite diagnosis has been made. Maybe you just have to re-plug a loose connector. Since the EVAP system is part of the emissions control system you might have warranty coverage.


0705 (PO440)
Diagnostic Trouble Code 0705 points to a problem with the Evaporative Emission Control System.

This malfunction is detected when the EVAP control system has a leak or the EVAP control system does not operate properly. (EVAP = EVAPorative emissions.)
Possible causes include...
- incorrect fuel tank vacuum relief valve
- incorrect fuel filler cap
- fuel filler cap vent remains open or fails to close
- foreign matter caught in fuel filler cap
- a leak in the line between the intake manifold and the
EVAP Canister Vacuum Control Valve
- foreign matter caught in the EVAP CVCV
- leaks in the EVAP canister or fuel tank
- leaks in the EVAP purge line (pipe and rubber tube)
- EVAP purge line rubber tube bent
- blocked or bent rubber tube to EVAP control system pressure sensor
- loose or disconnected rubber tube
- EVAP CVCV and circuit
- EVAP Canister Purge Volume Control Solenoid Valve and circuit
- absolute pressure sensor
- tank fuel temperature sensor
- MAP/BARO switch solenoid valve and circuit
- blocked or bent rubber tube to MAP/BARO switch solenoid valve
- O-ring of EVAP CVCV is missing or damaged
- water separator
- EVAP canister saturated with water
- EVAP control system pressure sensor
- refueling EVAP vapor cut valve
- ORVR system leaks


This is a "jackpot" DTC. It points to so many things you don't know what to check. It is often combined with another DTC which is more specific and therefore more helpful.


Good Luck,

Kevin
 
I'd be checking for fuel system leaks, or anything that could cause pressure loss in the fuel system, like a bad injector, or a bad seal on your gas cap, etc.
 
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