p0440 code on my 99 blazer
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Joined: Jan 2007
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RE: p0440 code on my 99 blazer
If you are making sure that the cap is on tight (3clicks) then you could have an Evap Emissions failure...there is a pressure valve on top of the fuel tank I think in the same assembly as the fuel pump...if this valve fails then when the computer commands a test for the Evap Emissions system then you would set a code... there is also a part upon the upper intake manifold in the back by the distributor...I think that is a sensor.
Here is some text from the Service Docment Dealers use from the 2005 GM Service DVD...
Circuit Description
The evaporative system includes the following components:
[*]The fuel tank[*]The EVAP vent solenoid[*]The fuel tank pressure sensor[*]The fuel pipes and hoses[*]The vapor lines[*]The fuel cap[*]The evaporative emission canister[*]The purge lines[*]The EVAP purge solenoid [/ul]
The evaporative leak detection diagnostic strategy is based on applying a vacuum to the EVAP system and monitoring the vacuum decay rate. The VCM monitors the vacuum level via the fuel tank pressure sensor input. At an appropriate time, the EVAP purge solenoid and the EVAP vent solenoid turn ON, allowing the engine vacuum to draw a small vacuum on the entire evaporative emission system. If a sufficient vacuum level cannot be achieved, a large leak or an EVAP system malfunction is indicated. The following conditions can cause this problem:
[*]A disconnected or malfunctioning fuel tank pressure sensor[*]A missing, malfunctioning, improperly installed, or loose fuel cap[*]A disconnected, damaged, pinched, or blocked EVAP purge line[*]A disconnected or damaged EVAP vent hose[*]A disconnected, damaged, pinched, or blocked fuel tank vapor line[*]A disconnected or malfunctioning EVAP purge solenoid[*]A disconnected or malfunctioning EVAP vent solenoid[*]An open ignition feed circuit to the EVAP vent or purge solenoid[*]A damaged EVAP canister[*]A leaking fuel sender assembly O-ring[*]A leaking fuel tank or fuel filler neck [/ul]
Any of the above conditions can set a DTC P0440.
Here is some text from the Service Docment Dealers use from the 2005 GM Service DVD...
Circuit Description
The evaporative system includes the following components:
[*]The fuel tank[*]The EVAP vent solenoid[*]The fuel tank pressure sensor[*]The fuel pipes and hoses[*]The vapor lines[*]The fuel cap[*]The evaporative emission canister[*]The purge lines[*]The EVAP purge solenoid [/ul]
The evaporative leak detection diagnostic strategy is based on applying a vacuum to the EVAP system and monitoring the vacuum decay rate. The VCM monitors the vacuum level via the fuel tank pressure sensor input. At an appropriate time, the EVAP purge solenoid and the EVAP vent solenoid turn ON, allowing the engine vacuum to draw a small vacuum on the entire evaporative emission system. If a sufficient vacuum level cannot be achieved, a large leak or an EVAP system malfunction is indicated. The following conditions can cause this problem:
[*]A disconnected or malfunctioning fuel tank pressure sensor[*]A missing, malfunctioning, improperly installed, or loose fuel cap[*]A disconnected, damaged, pinched, or blocked EVAP purge line[*]A disconnected or damaged EVAP vent hose[*]A disconnected, damaged, pinched, or blocked fuel tank vapor line[*]A disconnected or malfunctioning EVAP purge solenoid[*]A disconnected or malfunctioning EVAP vent solenoid[*]An open ignition feed circuit to the EVAP vent or purge solenoid[*]A damaged EVAP canister[*]A leaking fuel sender assembly O-ring[*]A leaking fuel tank or fuel filler neck [/ul]
Any of the above conditions can set a DTC P0440.
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