P0231 on Subaru: How to Diagnose & Fix
Fuel Pump Secondary Circuit - Low
2 Subaru models · 2 documented issues · 2 critical
P0231 on Subaru by model: symptoms, diagnosis and fix
Certain 2019-2021 Ascents are affected by a fuel pump recall (WRK-22, NHTSA 20V-701) where the low-pressure fuel pump impeller can deform due to excessive absorption of fuel components, particularly in regions with higher-concentration ethanol fuels. A deformed impeller reduces fuel delivery, causing engine stalling, rough running, or inability to start. This is a safety concern as stalling can occur without warning during driving. The recall was coordinated across multiple manufacturers using the same Denso fuel pump.
Common Symptoms
- Engine stalling without warning while driving
- Rough idle or engine misfires
- Extended cranking before engine starts
- Loss of power during acceleration
- Check engine light with fuel system codes
- Vehicle fails to start
How to Fix
Check recall status by VIN at subaru.com/owners/recalls or NHTSA.gov. Recall WRK-22 (NHTSA 20V-701) provides free fuel pump replacement at any Subaru dealer. The updated pump uses a revised impeller material resistant to fuel component absorption. If you experience stalling before recall repair, avoid situations where a stall could be dangerous.
Find a Subaru dealer
Choose to share your location for this search, or enter an area below. Your search location is sent to Google to find dealers.
Open Subaru dealer map in Google Maps ↗Call to confirm they service Subaru vehicles and check your VIN, recall eligibility, parts availability, and appointment options.
Sources for this issue (4)
2019 Crosstreks (along with various 2013-2020 Subarus) were built with Denso low-pressure in-tank fuel pumps whose plastic impeller absorbs fuel and swells. The swollen impeller binds against the pump body, causing rough running, no-start, and unexpected engine stalls at highway speed. Affected vehicles were subject to NHTSA recalls (including WRD-20); related class-action litigation remains pending (Seeger Weiss case 1:20-cv-0982, D.N.J.).
Common Symptoms
- engine stall without warning
- long crank or no-start when hot
- rough running
- check engine light with fuel pressure codes
How to Fix
Verify recall completion via Subaru VIN lookup; dealer will replace the in-tank low-pressure fuel pump assembly with a redesigned fuel-resistant impeller version at no charge. Eligible owners can also claim reimbursement via the Denso fuel pump class settlement.
Find a Subaru dealer
Choose to share your location for this search, or enter an area below. Your search location is sent to Google to find dealers.
Open Subaru dealer map in Google Maps ↗Call to confirm they service Subaru vehicles and check your VIN, recall eligibility, parts availability, and appointment options.
Sources for this issue (3)
P0231 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0231 mean on a Subaru?
P0231 stands for "Fuel Pump Secondary Circuit - Low." This code indicates the engine computer detected a low-voltage condition in the fuel pump's secondary (driver/output) control circuit. Many vehicles control the fuel pump through a relay or a dedicated driver module, and the computer monitors the voltage on that circuit to confirm the pump is being powered correctly. When the feedback voltage stays lower than expected, P0231 sets. Because the fuel pump supplies pressurized fuel to the injectors, this fault can cause hard starting, stalling, or no-start conditions. On Subaru it is documented across 2 models: Ascent, Crosstrek.
What are the most common causes of P0231?
The most common causes of P0231 are: Faulty fuel pump relay, Corroded or loose connector at the pump or relay, Damaged or shorted wiring in the pump power circuit, Poor ground for the fuel pump circuit, Failing fuel pump drawing abnormal current, Faulty fuel pump driver module, PCM/ECM internal driver fault (rare). The specific cause varies by vehicle.
How much does it cost to fix P0231 on a Subaru?
Repair costs vary widely with the root cause and Subaru model; each issue on this page carries its own estimate where one is published.
Looking for P0231 on a different make?
View P0231 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.