What does it mean?
Some evaporative systems test for leaks with a small pump module that pressurises the tank and canister and then watches how the pressure decays. The pump draws its air through a small filter so that dust and water cannot enter the sealed system. This code is stored when the module sees abnormal pump current or an abnormally slow pressure build up that matches a blocked intake filter rather than a leak in the tank. With a restricted filter the pump simply cannot move enough air, so no valid leak test can be completed and the evaporative monitor never finishes.
Symptoms
- MIL (check engine lamp) on with no change in the way the vehicle drives
- Evaporative readiness monitor that never completes, which blocks an emissions inspection
- Occasional leak detection codes appearing alongside this one
- Faint fuel odour if the canister side is affected as well
- The pump audibly running longer than usual after the vehicle is switched off
- The fault appearing more often after driving on wet, muddy or salted roads
Likely causes
- Filter element clogged with road dust, mud or salt because of its underbody position
- Water entering the filter and later freezing inside it or in the pump inlet
- Insect or rodent nesting material blocking the inlet
- Inlet hose to the pump module crushed, kinked or damaged
- Filter housing cracked or its cover displaced, letting debris straight in
- Carbon dust from the canister migrating into the pump inlet
- Aged pump module whose motor current has risen so that it looks like a restriction
How to fix it
- Read the pump data and any leak test result, and note whether the test aborted rather than reporting a leak
- Locate the pump module and its filter under the vehicle and inspect for mud, water and nesting debris
- Remove the filter and confirm that air passes through it freely
- Inspect the inlet hose and housing for crush damage, cracks and a cover that is not seated
- Replace the restricted filter, or the filter and pump assembly where the design requires it, and clear anything blocking the inlet area
- Run the evaporative test with a scan tool and confirm the pump now builds pressure normally
- Make sure shields and covers around the pump are refitted so the problem does not return