P2401: Leak detection pump circuit reading low
Evaporative emission system leak detection pump control circuit low
Severity: Monitor
P2401 is an EVAP-monitor fault on cars with a leak detection pump; it affects emissions, not how the car drives.
It gets more serious if:
- Inspect soon: Have it checked soon if you smell fuel or the engine idles roughly, which Toyota's fuel-in-EVAP bulletin lists with this code.
P2401 in short
P2401 means the leak detection pump control circuit read low when the computer checked it. The pump, its wiring, a charcoal canister problem or a loose fuel cap are the usual causes. On some Toyotas with P2419 and P043E the canister assembly is the cause. The car drives normally but will not pass emissions.
Some cars test the EVAP system with a small leak detection pump. The computer checks the pump circuit and sees whether the pump creates vacuum.
P2401 sets when the circuit voltage is lower than the computer expects; PartsAvatar lists the pump, wiring, canister valve, the PCM and a loose or missing cap.
A Toyota bulletin summary ties P043E, P043F, P2401, P2402 and P2419 to fuel in the EVAP system on some RAV4s.
Most likely causes
Cause 1: Leak detection pump or its wiring
Common general cause- Why it ranks here
- PartsAvatar lists the pump and its wiring first.
- What would change this
- Rises if the pump circuit tests low or open. Falls if the pump runs normally.
Cause 2: Fuel or charcoal contamination in the EVAP canister (some Toyotas)
Supported by vehicle data- Why it ranks here
- Toyota TSB-0046-10 (cached summary) ties this group of codes to fuel in the EVAP system on RAV4; an IATN thread reports canister replacement on an Scion xB and Corolla.
- What would change this
- Rises if P043E, P2419 and P2401 appear together on a Toyota. Falls on other makes or single-code cases.
Cause 3: Loose or missing fuel cap
Possible — needs testing- Why it ranks here
- PartsAvatar lists the cap, and recommends checking it before replacing parts.
- What would change this
- Rises if the cap is loose or worn. Falls if it seals.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Check the fuel cap seals fully and clear the code.
IfThe code returns
It meansLook at the pump and wiring.
IfThe code stays away
It meansThe cap was the problem.
Step 2: Have a shop test the leak detection pump circuit and look for fuel in the canister.
Warning:EVAP lines hold fuel vapor; keep ignition sources away.
IfThe circuit is open or low
It meansRepair the circuit or replace the pump.
IfP043E and P2419 are also stored on a Toyota
It meansCheck for fuel or contamination in the canister.
Points to: Fuel or charcoal contamination in the EVAP canister (some Toyotas)
Symptoms
- Check engine light
- Faint fuel odor
- Rough idle with fuel in the EVAP system Gets more serious: stop and have it checked.
Compare with: Check engine light came on after getting gas
How to fix
Step 1: Make sure the fuel cap clicks tight, then clear the code with a scan tool and see whether it returns.
Parts and cost context
- EVAP charcoal canister:On Toyotas with the full code group, canister replacement has been reported; confirm before buying. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
ToyotaYour car
2006–2010 · RAV4
Supported by vehicle dataToyota TSB-0046-10 lists P043E, P043F, P2401, P2402 and P2419 together with fuel in the EVAP system. Only the cached summary was read.
TSB-0046-10Status unverified
MIL on, fuel in EVAP system
2006–2010rav4 · NHTSA 10033407
Some vehicles show P043E, P043F, P2401, P2402 and P2419 with intermittent rough idle because of fuel in the EVAP system.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
01505Status unverified
MIL on, DTC P043E, P043F, P2401, P2402 and P2419
2005sequoia · NHTSA 10015869
Lists the same group of EVAP codes; summary does not state the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
P2401 questions
Will a new gas cap fix P2401?
Sometimes, as PartsAvatar lists the cap, but replace it only after checking the pump circuit.
Sources and review
- P2401 OBD error code summary
- Toyota TSB-0046-10: MIL on, fuel in EVAP system (P043E, P043F, P2401, P2402, P2419)
- P2419 DTC (IATN tech mail summary, April 2011)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error