What this code means
P0441 may mean the PCM is not seeing the expected fuel tank pressure change during EVAP purge operation.
What the vehicle may do
- The MIL may illuminate.
- The vehicle may otherwise drive normally.
- Fuel odor or fueling complaints can be possible on some EVAP faults, but they are not required for this code.
Possible fault areas
- A restricted EVAP filter or fresh-air path may be involved.
- A restricted, pinched, broken, or disconnected EVAP line may be involved.
- A purge vacuum supply restriction or purge solenoid concern may be involved.
- A fuel tank pressure sensor signal or 5-volt supply concern may be involved.
Diagnostic path
Opening and diagnostic direction
On this Ram 1500 with the 3.6 Pentastar, P0441 is an EVAP purge system performance code. In plain terms, the PCM is looking for the fuel tank pressure signal to move the right way when purge flow is commanded, and it may set this code when that pressure change does not look correct. The driver may only notice the MIL, and the fault area can be anything from a restricted EVAP filter or line, to a purge vacuum supply problem, a purge solenoid issue, or a fuel tank pressure sensor and 5-volt supply concern. Start with the basic system checks, then keep the diagnosis structured. This monitor runs only after certain EVAP conditions are already satisfied, so if other purge control or leak-related faults are present, handle those first instead of forcing this P0441 path.
Start with updates, then check code context
First, check for any service bulletins or PCM flash updates that apply to this fault. If one is available, perform the applicable bulletin or update, then leak test the EVAP system before continuing. If there are no applicable updates, move on. Turn the ignition on, read the DTCs with the scan tool, and record what is present. If there are active or pending purge solenoid control faults, or small or large EVAP leak faults, diagnose those paths first. If not, continue with the P0441 performance test.
Check the EVAP filter
Next, remove the EVAP filter and inspect it for blockage. A plugged filter can restrict the fresh-air side of the system and affect the purge performance result. If you find a problem, repair or replace as necessary, then verify the repair. If the filter is clear, keep going.
Run the forced monitor and use the result to choose the branch
Now check for an active condition with the scan tool routine. Before starting the ESIM/Purge Flow Forced Monitor, vent any pressure or vacuum in the fuel tank by opening the capless fuel filler with the vent, or by removing and installing the fuel cap. That brings the tank pressure closer to atmosphere and makes the routine more consistent. The routine runs the EVAP, large leak, and purge performance checks and gives you pass-fail direction. For purge performance, the important signal is the fuel tank pressure sensor. The pass thresholds are vehicle-specific, but the example uses a -50 Pa Pass Threshold: a pressure decrease of -20 Pa fails, and a pressure decrease of -60 Pa passes. If all monitors pass and both sides are well beyond the pass thresholds, the purge system is passing and does not need repair at that time. If everything passes but both sides are close to the thresholds, the system is still passing, but with only P0441 present you should be thinking about a possible partial restriction at the intake manifold or manifold hose. If side 1 passes, side 2 fails, and vacuum is very high, well below the ESIM regulation point of approximately -500 Pa, then look for a restriction at the fresh air inlet filter or hose. If removing that filter and hose does not bring vacuum back toward approximately -500 Pa, the ESIM internal vacuum vent valve is stuck closed. If side 1 or side 2 fails with little or no fuel tank pressure sensor change, and the ESIM switch closes while the large leak test fails, inspect the canister and related tubes for restriction, damage, or a partially broken purge tube. If side 1 or side 2 fails with little or no fuel tank pressure sensor change, the ESIM switch closes, and the large leak test passes, move into the fuel tank pressure sensor and canister-to-tank restriction checks. If side 1 or side 2 fails and the ESIM switch does not close, or the purge solenoid is suspected, move to the intake and purge vacuum supply checks.
Fuel tank pressure sensor response and 5-volt supply path
For the branch where the large leak test passes but the fuel tank pressure sensor is not showing the expected change, turn the ignition off. Remove the recirculation tube from the fuel tank pressure sensor, attach a hand vacuum pump to the sensor, and monitor the sensor value on the scan tool while applying vacuum. If the fuel tank pressure sensor value changes, the sensor is responding, so repair the restriction in the canister tube, recirculation tube, or multi-function control valve, then rerun the ESIM/Purge Flow Forced Monitor to confirm the system is repaired. If the sensor value does not change, disconnect the fuel tank pressure sensor connector, turn the ignition on, and measure the N8 5-volt supply circuit at the sensor connector. The voltage should be between 4.9 to 5.1 volts. If it is in that range, verify good pin-to-terminal contact at the connector. If the connector is good, replace the fuel tank pressure sensor, then rerun the forced monitor. If the 5-volt supply is not between 4.9 to 5.1 volts, repair the N8 5-volt supply circuit for an open or high resistance, then rerun the forced monitor. A lost 5-volt supply can leave the sensor signal stuck mid-range, which can make the PCM think tank pressure is not changing during purge.
Intake vacuum, manifold hose, and purge solenoid path
For the branch where purge flow or the purge solenoid side is suspect, start at the intake manifold vacuum port. Remove the manifold hose vacuum line at the intake manifold and inspect inside the port for restriction or blockage from flashing or carbon buildup. If the port is restricted, repair that restriction and rerun the forced monitor. If the port is clear, reinstall the manifold hose at the intake manifold, remove the hose at the purge solenoid inlet, start the engine, and let it idle. Check for sufficient engine vacuum at the purge solenoid inlet. If vacuum is not sufficient there, repair the broken or plugged manifold hose, then rerun the forced monitor. If inlet vacuum is sufficient, turn the ignition off, reconnect the inlet hose, remove the outlet hose that leads toward the canister, connect a vacuum gauge to the purge solenoid outlet, start the engine, and let it idle long enough for the purge solenoid to cycle on. If sufficient vacuum is present at the outlet, inspect the purge tube for damage, a break, a disconnection, or a blockage, then rerun the forced monitor after repair. If vacuum is not sufficient at the outlet, check the purge solenoid connectors. If the connectors are good, replace the purge solenoid, then rerun the forced monitor. When the purge solenoid is checked with a hand vacuum pump, use the stated applied vacuum: apply approximately 10 - 15 in. Hg. One important point here: a restricted vacuum supply may still show vacuum on a gauge, but not enough flow. Inspect the intake port and manifold hose closely even when vacuum appears to be present.
Verification and takeaway
Keep verification separate from the testing. After the repair that matches your branch, rerun the ESIM/Purge Flow Forced Monitor where the path calls for it, and confirm the system is repaired and the code stays gone. The takeaway on P0441 is to let the forced monitor tell you which side of the EVAP system to work on, then prove the restriction, sensor signal, 5-volt supply, or purge vacuum problem before replacing parts. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis often works best by using the scan tool forced monitor to split the fault into a restriction, pressure-sensor, electrical supply, or purge-flow path.
For more guided automotive diagnostics, visit STEP Diagnostics.
