What Does P1228 Mean?
DTC P1228 indicates the fuel injector driver circuit for cylinder 4 has a short-circuit condition to ground. This means the PCM has detected abnormally low resistance or direct grounding in the injector wiring or connector for cylinder 4. The engine will likely misfire on this cylinder and the PCM may disable the injector to protect the driver circuit.
Safety Warning
A shorted injector circuit causes a dead misfire on cylinder 4, leading to rough running, loss of power, and potential catalytic converter damage from unburned fuel. The vehicle should not be driven extended distances.
Common Causes
35%
Damaged or chafed injector wiring harness shorted to chassis ground
30%
Faulty fuel injector with internally shorted coil windings
20%
Corroded or water-damaged injector connector
10%
PCM injector driver circuit failure
5%
Pinched wiring at valve cover or intake manifold routing
Diagnostic Steps
1
Disconnect the cylinder 4 fuel injector electrical connector and measure resistance across the injector terminals (should be 11-18 ohms for most high-impedance injectors).
2
With the injector disconnected, check for continuity between each injector harness wire and chassis ground — there should be no continuity (infinite resistance).
3
Visually inspect the injector harness from the PCM connector to the injector for chafing, melting, or pinched wires, especially near the exhaust manifold and valve cover.
4
Check the injector connector for signs of corrosion, moisture intrusion, or bent/pushed-back pins.
5
If the harness checks good and the injector tests within spec, swap the injector with an adjacent cylinder to determine if the fault follows the injector or stays with the cylinder 4 harness.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
DTC P1228 indicates the fuel injector driver circuit for cylinder 4 has a short-circuit condition to ground. This means the PCM has detected abnormally low resistance or direct grounding in the injector wiring or connector for cylinder 4. The engine will likely misfire on this cylinder and the PCM m...
The most common cause of P1228 (Injector Circuit Cylinder 4 Short To Ground) is: Damaged or chafed injector wiring harness shorted to chassis ground
Typical repair costs for P1228 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A shorted injector circuit causes a dead misfire on cylinder 4, leading to rough running, loss of power, and potential catalytic converter damage from unburned fuel. The vehicle should not be driven extended distances.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1228 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection
Difficulty
Type
Manufacturer
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