What Does P1291 Mean?
The high-side driver circuit for one or more fuel injectors on bank 1 has detected a short to ground or battery voltage. This indicates a serious electrical fault in the injector control system.
Safety Warning
Vehicle may experience severe misfires, loss of power, or fail to start. May damage PCM if driven extensively. Avoid driving until repaired.
Common Causes
35%
Shorted fuel injector internal coil
30%
Wiring harness short to ground or power
20%
Water or oil intrusion in injector connector
15%
PCM injector driver circuit failure
Diagnostic Steps
1
Step 1: Disconnect all bank 1 injector connectors and clear codes to isolate which injector(s) are affected
2
Step 2: Measure resistance of each injector coil and compare to specifications
3
Step 3: Check for short to ground or voltage in injector harness with injectors disconnected
4
Step 4: Inspect injector connectors for oil, fuel, or moisture contamination
5
Step 5: Test PCM injector driver circuits individually using noid lights or oscilloscope
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
The high-side driver circuit for one or more fuel injectors on bank 1 has detected a short to ground or battery voltage. This indicates a serious electrical fault in the injector control system.
The most common cause of P1291 (Injector High Side Short To GND Or VBATT - Bank 1) is: Shorted fuel injector internal coil
Typical repair costs for P1291 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience severe misfires, loss of power, or fail to start. May damage PCM if driven extensively. Avoid driving until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1291 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Manufacturer
Recommended Tools
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