Tip & How-To about Mercedes-Benz E-Class

EVAP - Fuel Vapour Evaporative Control System

1.11) EVAP - Fuel vapour evaporative control system (actuator)


What is it? The EVAP system is a collection of pipes and devices designed to prevent fuel vapour emission to protect the environment.


Where is it located? Pipes run from the top of the fuel tank to the carbon (vapour trap) canister which can be located between the inner and outer fenders (wings), on the inner fender or on the firewall (bulkhead). A pipe connects the canister to the throttle: the pipe exits just in front of the throttle plate.


How does it work? The EVAP system passively stores the vapour from the fuel tank in a charcoal filled canister. When the engine is running above idle speed the ECU opens a purge valve to the pipe leading to the throttle body. A vent valve allows the ingress of air into the canister and this encourages fuel vapour to be drawn out through the purge valve to be added to the air intake mixture to be burnt. The opening of the purge valve cycles with engine speed. The purge valve should be closed during idle.



Symptoms of faulty EVAP

Associated OBD2 error codes DTCs: P0440 - P0459; P1441


  • Erratic idling - If the purge valve fails to close the ingress of unmetered air will compromise the ECU's ability to maintain a suitable air/fuel ratio.


How to check? Simply clamping off the pipe from the EVAP purge valve should result in an immediate improvement in engine idling performance. Remove the purge valve and try to blow through it. If there is resistance then the valve is mechanically OK. Applying voltage to the electrical connections should open the valve and remove any resistance to blowing.


How to fix? If the valve is jammed open permanently or fails to open when signaled to do so then replace it. It may be possible, taking the greatest of care in the process to open the valve to clean it up in the hopes of affecting a repair. If the solenoid, however, shows open-circuit due to an electrical short it is best to replace it.



NEXT 1.12) Oxygen (Lambda) sensor


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99 chrysler 300 m po455 smells like fuel when first starting up and at idle for extended periods run great


Hi there,

Code P0455 denotes "Evaporative Emmission Control System Malfunction".

The Evap system relates to petrol vapours which are recirculated and any excess fumes are absorbed by a little canister in the engine bay (look for rubber hoses going to a metal canistor).

This code generally triggers when it has detected a leak somewhere in the Evap system.

This could be anything ranging from petrol vapour leaking from the fuel cap (check for loose or incorrect fuel tank cap); faulty purge solenoid; charcoal canister is blocked/not working or a leaking hose etc.

You will need to check the entire system for a vapour leak somewhere, as leaking fuel vapour can be dangerous. Check the security of all rubber hoses.

Good luck.......



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Jun 05, 2011 | Chrysler 300M Cars & Trucks

1 Answer

error code p0440


Hi there,

Code P0440 denotes "Evaporative Emmission Control System Malfunction".

This code generally triggers when it has detected a leak somewhere in the Evap system. Could be anything ranging from vapour leaking from the fuel cap (check for loose or incorrect fuel tank cap); faulty purge solenoid; charcoal canister is blocked/not working or a leaking hose etc.

You will need to check the entire system for a vapour leak somewhere, as leaking fuel vapour can be dangerous.

Cheers,


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May 07, 2011 | 2001 Hyundai Elantra

1 Answer

I was told by a mechanic that my 2006 Saturn Ion needed a purge soleniode and vaccum canester. The gas sap light and engine light stays on. I replaced gas cap and they went out for couple of days now back on, and this id what they said I needed. HELP!!!




The purge solenoid valvend canister are part of the EVAP system. The automatic diagnostic method tests the integrity of the EVAP system for leaks by pressurizing everything and then checking to see if pressure is lost. The filler cap is the main seal to the gas tank and if this is loose then compromises the ability of the system to be pressurized. Put a film of grease around the rubber seal and fit the cap tightly.

The following is a brief overview of the system (any spelling anomalies are due to my British background). I hope you find it helpful :-



What is it? The EVAP system is a collection of pipes and devices designed to prevent fuel vapour emission to protect the environment.


Where is it located? Pipes run from the top of the fuel tank to the carbon (vapour trap) canister which can be located between the inner and outer fenders (wings), on the inner fender or on the firewall (bulkhead). A pipe connects the canister to the throttle: the pipe exits just in front of the throttle plate.


How does it work? The EVAP system passively stores the vapour from the fuel tank in a charcoal filled canister. When the engine is running above idle speed the ECU opens a purge valve to the pipe leading to the throttle body. A vent valve allows the ingress of air into the canister and this encourages fuel vapour to be drawn out through the purge valve to be added to the air intake mixture to be burnt. The opening of the purge valve cycles with engine speed. The purge valve should be closed during idle.


Symptoms of faulty EVAP

  • Erratic idling - If the purge valve fails to close the ingress of unmetered air will compromise the ECU's ability to maintain a suitable air/fuel ratio.


How to check? Simply clamping off the pipe from the EVAP purge valve should result in an immediate improvement in engine idling performance. Remove the purge valve and try to blow through it. If there is resistance then the valve is mechanically OK. Applying voltage to the electrical connections should open the valve and remove any resistance to blowing.


How to fix? If the valve is jammed open permanently or fails to open when signaled to do so then replace it. It may be possible, taking the greatest of care in the process, to open the valve to clean it up in the hopes of affecting a repair. If the solenoid itself, however, shows 'open-circuit' due to an electrical break it is best to replace it.

Mar 15, 2011 | 2006 Saturn ION

2 Answers

Check Engine Light came on, it was diagnosed as error code P0441 what does that mean


The Diagnostic Trouble Code table says for P0441 Evap Ctrl System Incorrect Purge:

General Description

The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel tank2_bing.gif from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustion. This valve is actuated by the purge control signal from the ECM and controls fuel2_bing.gif vapor from the canister to the intake manifold.
DTC Description

During "test of vapour generation" a new value from the tank pressure sensor is measured and compared with the start pressure at beginning of "test of vapour generation".
The ECM sets DTC P0441 if the pressure signal decrease occurs and the difference is below the predetermined threshold. If same error code is set in the next driving cycle, the ECM illuminates the MIL.

Unfortunately, this is not the 'turn gas cap 3 clicks" fault. Your likely cause is the PCSV valve is sticking in the open position.

Your test inspection procedure is:

System Inspection
PCSV Inspection
1. Ignition "OFF" .
2. Disconnect the hose leading from the PCSV to the intake manifold at PCSV.
3. Using a vacuum pump, apply specified vacuum(Approx. 15 in, Hg) to the manifold side of the valve and verify PCSV holds vacuum.
4. Ignition "ON" & Engine "OFF".
5. Install scantool and select "EVAP PURGE VALVE" on the Actuation Test mode.
6. Activates "EVAP PURGE VALVE" by pressing "STRT(F1)" key.
7. Verify PCSV release vacuum while valve is activating(should hear a faint click from PCSV).
8. Repeat this procedure 4 or 5 times to ensure PCSV reliability.
9. Is PCSV working properly?
YES
? Thoroughly check fuel vapor hoses and hose clamp and replace as necessary. Go to "Terminal and connection inspection" procedure.
NO
? Thoroughly check fuel vapor hoses and hose clamps between PCSV and intake manifold. Repair as necessary.
If OK, test with a new PCSV and check for proper operation. If problem is corrected, replace PCSV and go to "Verification of Vehicle Repair" procedure

I realize you probably do not have a ScanTool, as this is a dealer testing console. You should start by inspecting the hoses and connection to the PCSV.

Jun 04, 2010 | Hyundai Motor 2003 Sonata

1 Answer

im getting a P0441 EVAP emission control system purge flow fault code on my 2002 hyundia elantra. im guessing a good start would be to blow out the lines and replace the vacuum switch? where are they?


P0441 : Evap. Emission System Incorrect Purge Flow

General Description
The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustlon. This valve is actuated by the purge control signal from the PCM and controls fuel vapor from the canister to the intake manifold.
Possible Cause : ● Leakage on hose to PCSV ● Defective PCSV

Aug 09, 2008 | Hyundai Elantra Cars & Trucks

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