Welcome to the Corvette Forums at the Corvette Action Center!

P0441 EVAP system no flow during purge


Active member
Nov 6, 2003
98 pewter mn6 coupe
Help, I have this code and have no idea how to bust it. I'm pretty good with electronics etc but this one's got me. I've so far found this info:
Circuit Description

The EVAP vacuum switch is a normally closed switch connected to ground. The EVAP vacuum switch is mounted in the vacuum line between the EVAP canister and the EVAP solenoid. The PCM supplies 12 volts to the EVAP vacuum switch. When the PCM commands the EVAP canister purge solenoid valve open (purge ON) and the engine vacuum draws the evaporative emissions from the canister, the EVAP vacuum switch opens (signal voltage high) providing feedback to the PCM that the EVAP system is operating. When the PCM commands purge OFF, the EVAP vacuum switch closes (signal voltage low) confirming purging has ceased.

Conditions for Running the DTC

DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0443, P1120, P1220, P1221, P1441 are not set.
ECT is less than 115°C (239°F)
IAT is greater than 3°C (37°F) when first started, but less than 80°C (176°F) when operating.
The difference between ECT and IAT is not greater than 10°C (18°F) at engine start up.
Engine speed is between 800 and 3000 RPM
TP Angle is between 8% and 60%
MAP is greater than 15 kPa
BARO is greater than 75 kPa
Purge duty cycle is above 90%

Conditions for Setting the DTC

The PCM detects low signal voltage on the EVAP vacuum switch signal circuit when the PCM is commanding purge.
The fault exist for 5 seconds.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids

Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.

Before replacing any components, visually/physically check for the following:

Mis-routed harness
Rubbed through wire insulation
Broken wire inside the insulation
Kinked or damaged vacuum hoses
Physically damaged system components
Inspect components and vacuum lines for traces of carbon or other contaminants. The presence of foreign material may be causing a restriction in the system or preventing the solenoid valve from closing properly. Either condition may cause a DTC to set.
For an intermittent, refer to Symptoms .

Test Description
The numbers below refer to the step numbers on the diagnostic table.

DTC P0443 indicates that the purge control solenoid may not be operating correctly. This condition must be corrected first.

I do not have the P0443, and have looked everywhere under the coil covers for any kinked wires etc. This code only started popping up after I removed the intake manifold to change the rear/passenger air check valve. Not sure if its a coincidence or if it was related.

I do not have the diagnostic tool which can tell the solenoid to "activate" so I'm not sure how I can diagnose this. It does not seem like a common code as a search here and on the other forums turned out nothing. Car seems to run OK, but from what it sounds like the valve that allows the engine vaccuum to suck the vapors out of the charcoal canister in the back near the gas tank. I havent gotten under the car yet to see if there's anything busted down there.

PS the car is a 98 coupe M6.


Well-known member
Jul 5, 2004
So Cal
2004 Millenium Yellow Coupe
[/QUOTE]This code only started popping up after I removed the intake manifold to change the rear/passenger air check valve. Not sure if its a coincidence or if it was related. [/QUOTE]

I believe this code can be caused by something a simple as a vacuum leak. On other vehicles I've heard it may be caused by just a loose or defective gas cap but that is a bit unclear. I would be looking for a missed or loose or cracked vacuum hose since I do not believe in coincidences.
There is some good info available on this subject here.


Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!



Advertise with the Corvette Action Center!

Double Your Chances!


Top Bottom