P0257 Code Meaning and Next Steps

First checks take 10 to 20 minutes for the first checks. No special tools are usually needed for the first checks.

Can you keep driving?

Stop driving if any of these apply

!The vehicle suddenly runs much worse, loses power sharply, or the check-engine light starts flashing.
!There is a strong smell, smoke, overheating, or any symptom that suggests a real-time safety problem rather than a stored code alone.

If the light is steady and the vehicle still drives normally: Often yes for a short time, but it should not be ignored if drivability changes are obvious.

What to check first

Step-by-step checks

1
Safety first
Work on the fuel system only with the engine off and keep sparks, hot surfaces, and open flames away from the area
2
Free - no tools
Inspect the secondary metering connector and harness for damage, corrosion, or a pin that has backed out
3
Basic tool needed
Check whether the engine is losing power or struggling to maintain fuel delivery under load
4
Basic tool needed
Verify filter and pump condition before blaming the valve
5
Basic tool needed
If scan data is available, compare commanded fuel delivery with the actual response of the secondary path
6
Basic tool needed
Confirm whether the vehicle uses a dedicated secondary metering valve or just one control path

If the code returns

-If the circuit is shorted, repair wiring before replacing the valve.
-If the valve is electrically sound but fuel delivery is still low, the supply side becomes more likely.
-If the code returns after connector repair, recheck terminal fit and the control feed.

Background

What this code means

P0257 is a generic OBD-II code for a low-input secondary fuel metering control circuit.

That usually means the ECU is seeing a signal that sits lower than expected on the alternate fuel metering path. A shorted wire, weak valve, or supply-side fuel restriction can all create that pattern.

Diagnosis

Common causes

Most common

Short-to-ground in the secondary circuit

A wiring fault can pull the signal lower than expected.

Common

Weak secondary metering valve

The valve may not respond properly to the control command.

Common

Fuel supply restriction

A clogged filter or weak lift pump can make the signal look low.

Possible

Connector contamination

Fuel, corrosion, or moisture in the connector can distort the circuit.

Avoid these mistakes

What not to do

xDo not replace the pump before checking the supply-side and connector condition.
xDo not overlook a clogged filter or air intrusion that could be causing the low reading.

Parts

Parts that may need replacing

PartTypical costNotes

Secondary fuel metering valve$80-$400Relevant when the secondary valve itself is not responding correctly.

Fuel filter or lift-pump repair$20-$220Worth checking when the fuel supply is actually weak.

Connector or wiring repair$20-$160Important when the circuit is being pulled low by damage or corrosion.

Related OBD codes

P0252

P0252 means the fuel metering control circuit is not responding properly.

P0253

P0253 means the fuel metering control circuit is reading too low.

P0254

P0254 means the fuel metering control circuit is reading too high.

Source notes

Generic OBD-II (SAE J1979 / ISO 15031-5). P0257 was seeded from dtcdb and then expanded around low secondary fuel metering faults, especially short-to-ground wiring issues and weak alternate valves.

This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.

This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.

Last reviewed: 2026-04-10

Reference: Open reference

P0257 - The Secondary Fuel Metering Control Signal Is Reading Too Low