P0204: Injector Circuit/Open – Cylinder 4
Key takeaways
- P0204 is an electrical code: the engine computer can't drive the cylinder 4 fuel injector properly, so that cylinder usually misfires.
- Drive only short, gentle trips; if the check engine light flashes or you smell raw fuel, stop.
- Check the injector connector and wiring first ($100–$250); a new injector costs $250–$600.
- 6 complaints filed with NHTSA mention P0204; it is a code owners rarely quote.
- 62 manufacturer bulletins name P0204, including a software update for the 2014 Chrysler 200 and harness fixes on GM full-size trucks.
What P0204 means
The engine computer can’t operate the fuel injector for cylinder 4 the way it should. Scanners call it Injector Circuit/Open – Cylinder 4. The computer fires each injector by switching its circuit, and it watches the voltage on that circuit while it does. When what it sees doesn’t match what it commands, most often because the circuit is open, it sets P0204.
It’s a circuit code, not a clogged-injector code. Something between the computer and the injector’s coil isn’t carrying current. That can be the injector itself, but the connector and the wire come first.
Is it safe to drive?
Short trips only. Without a signal, the cylinder 4 injector usually stays shut, the cylinder misfires, and you get a rough idle, less power and often misfire code P0304. With a steady light, drive gently to a shop. Stop and have the car towed if the check engine light flashes, the engine stalls, or you smell raw fuel, which can mean the injector is stuck open instead of dead.
Causes, ranked
| Cause | How you confirm it | Typical cost (US independent shop, 2026) |
|---|---|---|
| Loose, unplugged or corroded injector connector | Look at the cylinder 4 injector plug; common right after intake, plug or coil work | $100–$250 (sometimes just a reseat) |
| Damaged injector wiring | Chafed, heat-damaged or chewed harness; test for power at the plug and continuity back to the computer | $100–$250 |
| Failed injector (open coil) | Injector resistance out of spec; on port injection, swap with a neighbor and the code moves | $250–$600 for one injector |
| Lost power feed to the injectors | Blown fuse or bad relay; several injector codes at once | $100–$250 |
| Software fault | Shop finds a matching bulletin for your engine | $100–$200; often $0 under a bulletin |
| Engine computer injector driver failed | Wiring and injector test good, but the computer’s output is dead | $800–$1,800 plus programming |
What to check first
- Read all the codes. P0204 alone points to cylinder 4’s own circuit. Several injector codes, or P0200, point to a shared fuse, relay or harness.
- Inspect the connector. Unplug it, check for corrosion, bent pins and a broken lock, and reseat it firmly.
- Check power at the plug with a test light, key on. No power means a fuse or feed wire.
- Measure the injector’s resistance against your engine’s spec.
- Swap injectors on a port-injected engine to see if the code follows. On direct injection, leave it to a shop; those injectors run on high voltage and high fuel pressure.
Most bulletins point at wiring. GM’s for the 2021–2022 Escalade, Silverado 1500, Sierra 1500, Suburban and Yukon XL replace the injector with the wiring harness, and a GM note for the 2021 Escalade ESV says to inspect the engine harness for damage. Chrysler has an engine-computer software update for P0204 on the 2014 Chrysler 200, and Jeep has a bulletin for P0204 on the 2022 Grand Wagoneer.
What it costs
The cheap outcome is a connector or wire repair, $100–$250. The common outcome is one fuel injector, $250–$600, with direct-injection engines at the top. The expensive outcome is an engine computer, $800–$1,800 plus programming, which is rare and should only follow a full circuit test. An hour of diagnosis, usually $100–$180, costs less than buying an injector for a broken wire. If you want to go over your codes first, ask our AI mechanic.
Related codes
P0204 usually sets with P0304 and sometimes P0300. With P0201 it matches a Mazda bulletin pattern; with P0202 and P0203 as well, suspect the shared power feed. If the engine stumbles or bucks, see car sputtering and car jerks when accelerating.
What owners report to NHTSA
6 complaints filed with NHTSA mention P0204, 5 of them since 2015, across 6 different models. The component owners most often filed it under: electrical system.
Manufacturer service bulletins that name P0204
62 technical service bulletins and manufacturer communications filed with NHTSA mention P0204, from 14 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- CADILLAC ESCALADE NA (2021, 2022), bulletin 10211935: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
- GMC SIERRA 1500 (2021, 2022), bulletin 10211935: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
- CHEVROLET SUBURBAN (2021, 2022), bulletin 10211935: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
- CHEVROLET SUBURBAN 1500 (2021, 2022), bulletin 10213243: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
- CADILLAC ESCALADE (2021, 2022), bulletin 10213243: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
- CHEVROLET SILVERADO 1500 (2021, 2022), bulletin 10214874: This technical bulletin provides a procedure to replace the fuel injector and the wiring harness to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated with DTC P0201, P0202, P0203, P0204, P0205, P…
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.
Frequently asked questions
Does P0204 mean the injector is bad?
Not necessarily. P0204 means the computer sees a problem in the injector's electrical circuit. A loose connector, a corroded pin or a damaged wire sets the same code, so test those before buying an injector.
Can I drive with P0204?
Short, gentle trips to a shop are usually fine if the light is steady. Cylinder 4 is probably not getting fuel, so the engine runs rough. A flashing light, a strong fuel smell or stalling means stop.
Can a V6 or V8 set P0204?
Yes. Every engine with four or more cylinders has a cylinder 4. Where it sits depends on the maker's numbering, so look it up for your engine before unplugging anything.
Why do P0201 and P0204 show up together?
Look for something the two circuits share, such as a harness section or connector. Mazda has a bulletin for this exact pairing on the 2013–2017 Mazda3, CX-5 and Mazda6.