What Does P1225 Mean?
P1225 indicates a short-to-ground condition in the fuel injector circuit for cylinder 1. The ECM has detected that the control line for the cylinder 1 injector is making unwanted contact with vehicle ground, causing excessive current draw or preventing proper injector control. This may result in the injector staying energized, not firing, or firing erratically.
Common Causes
30%
Injector harness wiring chafed against the engine block or ground point
25%
Internally shorted cylinder 1 fuel injector with ground fault
20%
Corroded connector allowing moisture ingress and ground path
15%
Damaged wire insulation from heat exposure near the exhaust manifold
10%
ECM injector driver circuit failure pulling the line to ground
Diagnostic Steps
1
Review freeze frame data and check for companion codes P0201 (injector circuit) and P0301 (misfire) for cylinder 1.
2
Disconnect the cylinder 1 injector connector and measure resistance between each injector wire and engine ground. Any low resistance reading indicates a ground short in the harness or injector.
3
With the injector disconnected, check the harness side only for shorts to ground from the ECM to the connector to isolate wiring vs. injector fault.
4
Inspect the cylinder 1 injector harness for areas where insulation has worn through, particularly where wires contact the valve cover, engine block, or metal brackets.
5
Measure the injector coil resistance between its terminals and between each terminal and the injector body to check for internal ground shorts.
6
Repair wiring insulation damage or replace the shorted injector, clear codes, and verify proper operation by monitoring injector current waveform.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
P1225 indicates a short-to-ground condition in the fuel injector circuit for cylinder 1. The ECM has detected that the control line for the cylinder 1 injector is making unwanted contact with vehicle ground, causing excessive current draw or preventing proper injector control. This may result in the...
The most common cause of P1225 (Injector Circuit Cylinder 1 Short To Ground) is: Injector harness wiring chafed against the engine block or ground point
Typical repair costs for P1225 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A ground-shorted injector circuit can cause cylinder 1 to misfire or flood, leading to rough running and potential catalytic converter damage. If the injector stays open from the short, it can cause hydro-lock risk and exhaust system overheating.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1225 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
