EVAP System Operation

Explain the operation of the EVAP system. The EVAP system is in charge of recovering the excess fuel vapors and re-introducing them into the engine. It isn't just an emission system. If it malfunctions is also has a huge effect on engine performance and certain components operation will be cancelled by the ECM if the EVAP system fails. Learn how they operate here and how to test. The OBD-II scanner or Scan-1 is used to diagnose these systems and evaluate the process. See how it works.

Category:

Autos & Vehicles

Tags:

• EVAP
• evaporative system
• automotive
• diagnostics
• auto
• mandy concepcion
• auto repair
• auto diagnostics
• evaporative
• emissions
• Mandy Concepcion
• Scan-1
• P0440
• P0441
• P0442
• P0443
• P0444
• P0445
• P0446
• P0447
• P0448
• P0449
• P0450
• P0451
• P0452
• P0453
• P0454
• P0455
• P0456
• P0457
• P0458
• P0459
• P0465
• P0466
• P0467
• P0468
• P0469
• car

[FxXSMALLSXxF]

DONT USE A TEST LIGHT ON ECM CIRCUITS. You will jack sh!t up. Use a multimeter

[ADPTraining]

@FxXSMALLSXxF Hello, thanks so much for posting. Your assertion is wrong. You use a mutimeter for many things ECM, but to stress a circuit, as in proving a power or a ground circuit you use a test light. A regular incandescent test-light draws a nominal 300mA, enough to stress a small circuit. In other cases you may even have to use a higher load, as a head light substitution. When proving a false ground, if you don't use a test light you'll never find a 10 Ohm resistance, which will cause havoc

[ADPTraining]

@FxXSMALLSXxF Thanks so much for posting. You need stress the circuit. A TL is the least load device you can use to test any ECM circuit. A mutimeter is used to test electronic issues, not electrical problems. Good luck.

[ADPTraining]

Well, it is a pesky code but will not make the car leave you stranded. Your Neon uses an LDP pump. Follow the large hose that leaves the LDP pump to the rear of the vehicle or the charcoal canister. Try and isolate the small leak. Driving around with scanner connected will not help you. Do not erase codes. You may find leak by crimping the fuel vapor hoses, pressurizing the system with 1/4 PSI and see if still leaks. It is a hard job to do but not impossible. good luck...

[lolamizanin]

p0456  code has been coming on for my 2001 dodge neon for so long now I am ready to just straight blow my car up....... Currently driving around with Diagnostic Machine connected to my car in hopes of code clearing soon. anybody got any idea how to fix this problem

[getplaning]

Vac-u-um...LOL

[dirtylilrat]

good info but the VOICE is fucking STUPID..

[tomkkkkk]

PCV and Purge valves are a common failure especially on VW golfs. I am a Vw tech in training.

[ADPTraining]

@ADPTraining CONTINUED: If this happens right away then it is definitely an electrical fault. If it takes a while for the DTC to set, then either the electrical fault is not present at all times or it is related to vibrations or loose connections. Keep me posted. Good luck.

[ADPTraining]

@kelectr0n It is very odd that you'd get a DTC related to electrical and the cause being a performance problem. Keep in mind this: The ECM looks at the return voltage from the vent valve ground wire at all times. If just for an instant this voltage is lost, such DTC is generated. Resistance in the wires is also a problem.

I rarely recommend it, but at this time I would erase the DTC and drive the vehicle a bit to see if the same DTC is generated.