P0149 Fuel Timing Error

P0149 points to a fuel timing error. The controller detected fuel injection or pump timing behavior outside expected limits.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not adjust mechanical timing or replace pumps until command, feedback, and engine timing data are compared.

Symptoms of P0149

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0149

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Review injection timing command, actual timing feedback if available, fuel pressure, crank and cam signals, RPM, and load.
Inspect timing control solenoids, fuel quality, pump timing mechanisms, wiring, connectors, and related crank/cam correlation codes.
Check whether the fault appears during start, acceleration, high load, cold operation, or after fuel pump or timing service.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.