Ford F-150 check engine light: what it means and what to do
01 · Read the dashboard
Check engine light or wrench light?
An F-150 has two amber warnings that get confused: the check engine light, shaped like an engine, and the powertrain light, a wrench. They mean different things, and what you should do depends on which is on, whether it flashes, and whether both are lit.
The short version
Steady check engine light: an emissions or engine fault. Have it checked soon. Flashing check engine light: a possible misfire. Slow down and have it serviced right away. Wrench and check engine light together: Ford says to stop as soon as it is safe.
| What you see | What Ford says it means | What to do |
|---|---|---|
| Check engine light, steady | The diagnostics system has found a malfunction in the emission control system | Have it checked soon |
| Check engine light, flashing | The engine may be misfiring, and the heat could damage the catalytic converter | Have it serviced immediately |
| Wrench light | A powertrain or four-wheel-drive fault that is not emissions-related | Have it checked as soon as possible |
| Wrench light, flashing | A powertrain fault | Reduce speed right away and have it checked as soon as possible |
| Wrench and check engine light together | A powertrain fault that can reduce power or stop the engine | Stop as soon as it is safe |
From the 2025 F-150 owner’s manual, pages 232 and 233.
02 · Common causes
Why the light comes on in an F-150
The fuel filler
The F-150 has a capless filler. A Check Fuel Fill Inlet message or a light right after fueling often means the inlet did not close. Do not pry it open; use Ford’s funnel only when filling from a can.
EVAP leaks
Leaks in the fuel-vapor system’s hoses, seals, or purge valve set codes without changing how the truck drives.
Misfires
Worn plugs or failing coils. P0307 and P0308 exist only on the V8, the 5.0L’s two extra cylinders.
Lean codes
P0171 and P0174 mean too much air for the fuel on one or both banks: a vacuum leak, a sensor, or a fuel delivery problem.
Cam timing
Crank and cam correlation codes can accompany timing faults on the EcoBoost engines. See the next section.
Low battery voltage
A weak battery can confuse sensors after a cold night. A battery test rules it out.
03 · 3.5L and 2.7L EcoBoost
Cam phaser bulletins and the 2.7L recall
Some 3.5L EcoBoost F-150s make a brief rattle on a cold start, traced to the variable cam timing units. Ford has published repair procedures for it:
- TSB 18-2305: 2011 to 2015 F-150 3.5L EcoBoost built on or before May 29, 2015.
- TSB 20-2191: 2017 and 2018 F-150 3.5L built on or before July 10, 2018.
- TSB 23-2143: 2017 to 2020 F-150 3.5L built on or before Nov. 30, 2019. It describes a noise of 2 to 5 seconds after the truck has sat for six hours or more, and code P164C may be stored.
A service bulletin is a repair procedure, not free coverage: whether the repair is covered depends on your warranty. Separately, recall 24V-635 (Ford 24S55) covers 2021 and 2022 F-150s with the 2.7L EcoBoost, whose intake valves may crack and break, with a possible loss of power. Recall repairs are free. Check your VIN for open recalls.
04 · What to do
Steps to take when a light comes on
- Check which light it is. Wrench and check engine together: stop when safe. Flashing: slow down and get it serviced.
- If you are towing, reduce the load on the engine and head for somewhere safe to stop.
- Think about the last fill-up. A filler that did not close is a common cause right after fueling.
- Do not clear the code yourself. It erases the information the technician needs.
- Book a diagnostic. Soon for a steady light, right away for anything flashing.
05 · Emissions testing
The check engine light and the Illinois emissions test
A lit check engine light with stored trouble codes fails the Illinois emissions test. Clearing the codes right before the test does not help: the readiness monitors reset, and a 2001 or newer vehicle with more than one monitor not ready is turned away and has to come back.
Whether your F-150 needs the test depends on the ZIP code it is registered in. Huntley (60142), Woodstock (60098), and Hampshire (60140) are outside the testing area. Algonquin, Lake in the Hills, Crystal Lake, Carpentersville, Elgin, and McHenry are inside it. The nearest station to our store is at 195 Liberty Road in Crystal Lake. Our areas we serve page has the rule for each town.
Test notice on the counter? Get the light diagnosed now, not the week the test is due.
06 · Trouble codes
Codes you may see on an F-150
| Code | What it points to |
|---|---|
| P0171 / P0174 | System too lean, bank 1 / bank 2 |
| P0300 to P0308 | Misfire, random or by cylinder. P0307 and P0308 only on the V8. |
| P0420 / P0430 | Catalytic converter efficiency below threshold, bank 1 / bank 2 |
| P0016 / P0017 | Crankshaft and camshaft position correlation, bank 1 sensor A / B |
| P164C | Listed in Ford TSB 23-2143 for the cam phaser noise on some 3.5L EcoBoost trucks |
| P0455 / P0456 | EVAP system large leak / very small leak |
| P1450 | Ford code: unable to bleed up fuel tank vacuum |
Generic definitions per SAE J2012; P164C and P1450 are Ford-specific. Only a diagnosis confirms the failed part.
07 · At Huntley Ford
What happens when you bring it in
A technician reads the stored codes and the freeze-frame data, which records the conditions when the fault happened. A code points to a system, not a part, so the next step is testing that system to find what actually failed. You get the finding and the price before any repair starts.
We also check your VIN for open recalls and Ford programs, which are free when they apply. Book a diagnostic online, call (847) 669-6060, and see directions and hours for the service department’s times.
08 · FAQ
Questions about the F-150’s warning lights
What does the wrench light mean on an F-150?
Ford calls it the powertrain warning light: a fault in the powertrain or four-wheel-drive system that is not emissions-related. If it comes on together with the check engine light, Ford says to stop as soon as it is safe.
Can I keep driving with the check engine light on?
With a steady light and nothing else wrong, for a short while, but have it checked soon. Not with a flashing light, with the wrench light also on, or with shaking or lost power.
Can I tow with the check engine light on?
It is best not to. Towing puts more load on the engine and exhaust, which makes a misfire or overheating fault worse. Have the code read before your next trip with a trailer.
Is the 3.5L EcoBoost cold-start rattle covered?
Ford has published repair procedures for it, but a bulletin is not an extended warranty. Coverage depends on your truck’s warranty status. We can check your VIN.
Will the light fail my emissions test?
Yes, a lit light with stored codes fails. Whether your truck is tested depends on its ZIP code: Huntley, Woodstock, and Hampshire are outside the testing area. Diesel vehicles are exempt.
09 · Sources
Where this information comes from
Every source was read Sept. 23, 2026. For the Escape, see our Escape check engine light guide.
- Ford: 2025 F-150 owner’s manual
- TSB 18-2305, TSB 20-2191, and TSB 23-2143, via NHTSA
- NHTSA: recall 24V-635
- Illinois EPA: vehicle emissions testing and Illinois Air Team questions
- The Vehicle Emissions Inspection Law, 625 ILCS 5/13C-5, for the ZIP codes tested
Get the light read in Huntley
Book a diagnostic online, or call and tell us which light is on.