What Does P1272 Mean?
The ECM has detected a high-to-low side short circuit in the cylinder #7 fuel injector driver circuit. This code applies to engines with seven or more cylinders, such as V8, V10, or V12 configurations. The short between the injector's power supply and ground control wires prevents proper fuel injection on cylinder #7, causing a misfire on that bank of the engine.
Safety Warning
A misfiring cylinder #7 causes rough running and reduced power, particularly noticeable on the affected engine bank. Unburned fuel entering the exhaust can overheat and damage the catalytic converter. The shorted circuit poses a risk of damaging the ECM driver.
Common Causes
35%
Wiring harness damage near the cylinder #7 injector with high and low side conductors shorting together
30%
Internal short circuit in the cylinder #7 fuel injector coil
20%
Corrosion or contamination in the cylinder #7 injector electrical connector
15%
ECM injector driver circuit failure for cylinder #7 output
Diagnostic Steps
1
Check for cylinder #7 misfire code (P0307) and any other injector driver codes to determine if the problem is isolated or affects multiple cylinders.
2
Locate cylinder #7 on your engine and disconnect the fuel injector connector. Inspect for corrosion, heat damage, or debris between the connector pins.
3
Measure the injector coil resistance with a multimeter and compare to manufacturer specifications. Also verify no continuity exists between the injector terminals and the injector body.
4
With the injector disconnected, check the harness wires for continuity between the two conductors — any continuity indicates a wiring short.
5
Swap the cylinder #7 injector with an adjacent cylinder injector, clear codes, and run the engine to determine if the fault follows the injector or remains with the cylinder #7 circuit.
Estimated Repair Cost
$100 - $550
Parts + labor, varies by vehicle and location
The ECM has detected a high-to-low side short circuit in the cylinder #7 fuel injector driver circuit. This code applies to engines with seven or more cylinders, such as V8, V10, or V12 configurations. The short between the injector's power supply and ground control wires prevents proper fuel inject...
The most common cause of P1272 (Cylinder #7 High To Low Side Short) is: Wiring harness damage near the cylinder #7 injector with high and low side conductors shorting together
Typical repair costs for P1272 range from $100 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A misfiring cylinder #7 causes rough running and reduced power, particularly noticeable on the affected engine bank. Unburned fuel entering the exhaust can overheat and damage the catalytic converter. The shorted circuit poses a risk of damaging the ECM driver.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1272 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Manufacturer
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