cycle the key three times on off on and it will come up on the odometer instantly, just did it.

 

Anyone know how to fix this check engine light code, P0498 Evaporative Emission System Vent Valve Control Circuit Low?

I recently had my 2003 Quad Cab 2500 Dodge Ram serviced by a dealer for this code, P0496 Evaporative Emision System High Purge Flow. I had to pay 50 bucks towards the repair. I called them and told them I'm still getting Emissions errors and they said it would be a new charge to look at the above error. I don't want to keep paying these guys for guessing at fixes to solve my emissions problem.

I'm new to this forum and I have to say I am glad I found it. I love the tip about the ON-BOARD DIAGNOSTICS. That is sweet.

If anyone has an idea how to fix the P0498 error I would really appreciate it.

Thanks
DK

 

The question I have is what did they replace previosly. If they have replaced the NVLD check the way it is mounted. If it is upside down it could cause this code as well. I will try to find a picture on how it suppose to be mounted

Possible causes:
GOOD TRIP EQUAL TO ZERO
VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION
NVLD SOLENOID
NVLD SOL CONTROL CIRCUIT SHORTED TO GROUND
PCM

TEST ACTION APPLICABILITY

1 Start by reading PCM DTC(s) and record the related Freeze Frame data in any
DTC(s) are present.
Check the vehicle repair history.
If the vehicle has a repair history that pertains to the customer’s current complaint,
review the repair.
Inspect the vehicle for any aftermarket accessories that may have been installed
incorrectly.
Check for any service bulletin(s) related to the customer’s complaint or DTC(s).
If a service bulletin applies, follow the instructions per service bulletin.
Did the service bulletin repair the customer’s complaint?
All
Yes ! Testing Complete.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No ! Go To 2

2 Ignition on, engine not running.
With the DRBIIIt, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
All
Yes ! Go To 3
No ! Refer to the INTERMITTENT CONDITION Symptom (Diagnostic
Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5.


3 Turn the ignition off.
Disconnect the NVLD electrical harness connector.
Measure the resistance of the NVLD Solenoid coil.
Is the resistance between 7.5 to 8.5 ohms?
All
Yes ! Go To 4
No ! Replace the NVLD Assembly.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

4 Disconnect the PCM harness connector.
Measure the resistance between ground and the NVLD Sol Control circuit at the
NVLD electrical harness connector.
Is the resistance below 5.0 ohms?
All
Yes ! Repair the short to ground in the NVLD Solenoid Control circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No ! Go To 5

5 NOTE: Before continuing, check the PCM harness connector terminals for
corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay
particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
All
Repair
Replace and program the Powertrain Control Module per Service
Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.




OPERATION of the NVLD
Vehicles equipped with NGC engine control modules use an NVLD pump and system.Vehicles equipped with JTEC engine control modules use a leak detection pump. Refer to Leak Detection Pump (LDP) for additional information.

The Natural Vacuum Leak Detection (NVLD) system is the next generation evaporative leak detection system that will first be used on vehicles equipped with the Next Generation Controller (NGC). This new system replaces the leak detection pump as the method of evaporative system leak detection. This is to detect a leak equivalent to a 0.020" (0.5 mm) hole. This system has the capability to detect holes of this size very dependably.

The basic leak detection theory employed with NVLD is the "Gas Law". This is to say that the pressure in a sealed vessel will change if the temperature of the gas in the vessel changes. The vessel will only see this effect if it is indeed sealed. Even small leaks will allow the pressure in the vessel to come to equilibrium with the ambient pressure. In addition to the detection of very small leaks, this system has the capability of detecting medium as well as large evaporative system leaks.

A vent valve seals the canister vent during engine off conditions. If the vapor system has a leak of less than the failure threshold, the evaporative system will be pulled into a vacuum, either due to the cool down from operating temperature or diurnal ambient temperature cycling. The diurnal effect is considered one of the primary contributors to the leak determination by this diagnostic. When the vacuum in the system exceeds about 1" H2O (0.25 KPA), a vacuum switch closes. The switch closure sends a signal to the NGC. The NGC, via appropriate logic strategies, utilizes the switch signal, or lack thereof, to make a determination of whether a leak is present.

The NVLD device is designed with a normally open vacuum switch, a normally closed solenoid, and a seal, which is actuated by both the solenoid and a diaphragm. The NVLD is located on the atmospheric vent side of the canister. The NVLD assembly may be mounted on top of the canister outlet, or in-line between the canister and atmospheric vent filter. The normally open vacuum switch will close with about 1" H2O (0.25 KPA) vacuum in the evaporative system. The diaphragm actuates the switch. This is above the opening point of the fuel inlet check valve in the fill tube so cap off leaks can be detected. Submerged fill systems must have recirculation lines that do not have the in-line normally closed check valve that protects the system from failed nozzle liquid ingestion, in order to detect cap off conditions.

The normally closed valve in the NVLD is intended to maintain the seal on the evaporative system during the engine off condition. If vacuum in the evaporative system exceeds 3" to 6" H2O (0.75 to 1.5 KPA), the valve will be pulled off the seat, opening the seal. This will protect the system from excessive vacuum as well as allowing sufficient purge flow in the event that the solenoid was to become inoperative.

The solenoid actuates the valve to unseal the canister vent while the engine is running. It also will be used to close the vent during the medium and large leak tests and during the purge flow check. This solenoid requires initial 1.5 amps of current to pull the valve open but after 100 ms. will be duty cycled down to an average of about 150 mA for the remainder of the drive cycle.

Another feature in the device is a diaphragm that will open the seal in the NVLD with pressure in the evaporative system. The device will "blow off" at about 0.5" H2O (0.12 KPA) pressure to permit the venting of vapors during refueling. An added benefit to this is that it will also allow the tank to "breathe" during increasing temperatures, thus limiting the pressure in the tank to this low level. This is beneficial because the induced vacuum during a subsequent declining temperature will achieve the switch closed (pass threshold) sooner than if the tank had to decay from a built up pressure.

The device itself has 3 wires: Switch sense, solenoid driver and ground. It also includes a resistor to protect the switch from a short to battery or a short to ground. The NGC utilizes a high-side driver to energize and duty-cycle the solenoid.

 

I am driving a 2003 Dodge CTD six speed with about 65000. Lift pump went out last month and I replaced with an aftermarket from Diesel Performance Products. Well that pump failed and I just installed a replacement which was under warrenty. I am getting the following code in the odometer:

P0628 Fuel Pump "A" Control Circuit Low

Any ideas how to fix or have I already corrected the problem with the replacement pump? Also which pump is "Fuel Pump A?"

Thanks Everyone,

 

You might want to start a new post in the CTD section. You'll probably get more answers. Drew would be the person to ask, he is our diesel expert around here (among others, his name just comes to mind first)

 

Was the truck running when you put fuel in it?? Strangely, fueling up your vehicle while it's running can set off an emmisions code. AND it can take a day for the C/E light to come on. That happend with my neighbors Dodge, and that's what the mechanics came up with.

 

Interesting thread & feature!
I just bought an 04 Ram/hemi.
Do all 3rd gen trucks have this feature? When I do it, nothing flashes
does that mean no codes (problems) are coming up at this time??

Thanks
Sean

 

A while back there was a thread about a hose that tends to go bad causing a EVAP leak. I believe it was one of the hoses on the charcoal canister near the fuel tank. Does anyone think he might have a bad hose?

 

YES.... I had this same problem on my 2002 Dodge 1500 QC. WIth the engine running, slide under the truck on the driver side in front of the gas tank. ALL the evap stuff is loacted here. Check the big hoses for cracks, splits, etc. If the leak is big enough, you shoudl be able to hear it. Mine has a split about 1" long. Easily fixed. Good luck

 

i only see two rubber hoses, and they are both connected to the fill hole. where are the others?