🚨 Diagnostic Profile
Vehicle Make: CHRYSLER
Description: Evaporative Emission (EVAP) System Flow During Non-Purge. This fault indicates the EVAP system detected unexpected vapor flow or pressure behavior while the purge solenoid is commanded closed. Common causes include a stuck-open or leaking purge valve, a leaking vent or canister vent solenoid, or a cracked hose or fuel cap seal.
🚨 Repair Difficulty Tier
Tier: [Intermediate]
Diagnosis requires a smoke machine or pressure/vacuum test and familiarity with EVAP monitor logic. Most repairs (hoses, fuel cap, solenoid replacement) are straightforward once the leak path is isolated.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Confirm the fuel cap is present, undamaged, and sealing correctly; replace if cracked or worn.
- Visually inspect EVAP hoses and lines for cracks, brittleness, disconnections, or rodent damage.
- Check for active or stored DTCs and freeze-frame data using a scan tool.
- Inspect the purge solenoid and canister vent solenoid connectors for corrosion or loose terminals.
- Verify the physical mounting and condition of the EVAP canister (typically located along the vehicle underbody near or forward of the fuel tank), the purge solenoid (commonly mounted on or near the intake manifold/throttle body in the engine bay), and the canister vent valve/solenoid (usually integrated at or near the canister assembly, close to the fuel tank). Exact routing and mounting points vary by platform (e.g., Pacifica, 300, Charger, Durango, Ram), so confirm placement against the underhood emissions label or service information for the specific model and engine.
Step 2: Diagnostic Verification
- Command the purge solenoid and vent solenoid using the bidirectional scan tool and observe commanded versus actual states.
- Perform a smoke test on the EVAP system (introduce smoke at the service port with the system sealed) to locate leaks at hoses, canister seams, purge valve, and vent valve seals.
- With the solenoid energized, verify that battery reference voltage (nominally 12V) is present at the control circuit using a digital multimeter referenced to a known good chassis ground; then measure coil resistance at the solenoid connector (disconnected) and compare to the manufacturer’s specified range for that component — typical purge/vent solenoid coils fall in the tens of ohms, but always confirm against the OEM service specification for the exact part number installed.
- Verify that the purge valve does not pass vacuum or flow when de-energized, using a handheld vacuum pump — the valve should hold vacuum with no measurable bleed-down when commanded closed.
- Confirm ground circuit integrity at the EVAP solenoid control circuits by probing the ground leg of each connector and verifying continuity to chassis ground with no more than a nominal voltage drop (a few tenths of a volt) under load; an open or corroded ground will cause erratic solenoid operation and false flow-during-non-purge faults.
Step 3: Resolution & Reset Process
- Replace the faulty purge valve, vent solenoid, hose, or fuel cap as determined by verification results.
- Repair any wiring or connector faults found in the control circuits.
- Clear all DTCs with the scan tool and confirm no pending codes remain.
- Perform the EVAP monitor drive cycle: ensure the fuel tank is between approximately 15%–85% full, start the engine cold (coolant temperature below roughly 86°F/30°C with intake air temp within about 20°F of coolant temp), allow the PCM to complete its initial system checks at idle, then drive with a sustained steady-speed cruise (approximately 45–65 mph) for 10+ minutes to allow the PCM to run its leak-detection (pump or natural vacuum) routine. Avoid excessive throttle transients or stops during this window, as they can abort the monitor.
- Verify readiness monitors reach complete status using the scan tool and confirm the fault does not return after multiple drive cycles.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Purge solenoid valve — OEM/Mopar part number varies by model year and engine; verify exact part number via dealer parts catalog or VIN-specific lookup
- Canister vent solenoid — OEM/Mopar part number varies by model year and engine; verify via dealer parts catalog or VIN-specific lookup
- EVAP hoses, clamps, and quick-connect fittings as needed — sourced per platform
- Fuel cap (if required) — OEM or quality aftermarket equivalent rated for the vehicle’s fuel system
- Bidirectional OBD-II scan tool with EVAP solenoid control/test capability and a smoke machine with appropriate EVAP system adapters
Average Component Price:
- Purge solenoid valve: approximately $40–$120 (parts only)
- Canister vent solenoid: approximately $60–$150 (parts only)
- EVAP hoses and clamps: approximately $15–$60 depending on length/routing
- Fuel cap: approximately $15–$35
Estimated Labor Hours:
- Diagnosis and smoke testing: approximately 0.5–1.5 hours, depending on leak location complexity and canister accessibility
- Component replacement (purge valve, vent solenoid, hoses, or fuel cap): approximately 0.3–1.5 hours per component; canister vent solenoid replacement can run longer on platforms where the canister is mounted in a tight underbody location requiring partial fuel tank or skid plate removal
- Verification and drive cycle confirmation: approximately 0.3–0.7 hours shop time plus road test duration to complete the EVAP monitor
Total estimated out-of-pocket cost for diagnosis plus a single-component repair (e.g., purge valve or fuel cap) typically ranges from $150–$350 including labor; if both the purge and vent solenoids require replacement along with hose repairs, total costs can range from $350–$650 depending on regional labor rates and canister accessibility.