P0204: Cylinder 4 Injector A Circuit
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Short trips only.
Symptoms
- Cylinder 4 dead
- Rough idle
- Poor economy from enrichment on the remaining cylinders
Likely causes, most common first
- Injector 4 winding failed
- Wiring or connector fault
- Driver failure
- Harness damage at the end of the rail
Read P0204 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0204 is the circuit of injector 4 - on inline engines, the end of the rail, where the harness makes its final bend and wires fatigue first.
If multiple injector circuit codes appear at once, think supply, not injectors: on most cars all injectors share one feed from a relay or fuse, with the computer switching each ground individually. Every injector dead at the same moment is a blown feed; one injector dead is that injector's own circuit. The pattern of codes hands you the answer before the multimeter comes out.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0204
“I was driving and received a check engine light with “Service ESC” and traction control was disabled. Performed diagnostics and found P0300, P0304 and P0204 all relating to cylinder 4 misfire and injector issues on cylinder 4. Truck has just over 47,000 miles and may be related to the lifter issues that plague this engine design.”2023 Chevrolet Silverado 1500 · Dec 2024
Cars that report P0204 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0204?
Short trips only.
How much does it cost to fix P0204?
Typical US repair costs range from $60 for the simplest fix (connector repair) to $600 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0204. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.