What Does P1277 Mean?
The ECM has detected a high-to-low side open circuit condition in the cylinder #2 fuel injector driver circuit. An open circuit means there is a complete break in the electrical path to the cylinder #2 injector — either the power feed wire or the ECM control wire is broken or disconnected. The injector cannot be energized, resulting in a dead misfire on cylinder #2 with no fuel delivery to that cylinder.
Safety Warning
A completely non-functional cylinder #2 injector causes a persistent dead misfire with rough running, vibration, and substantial power loss. Unburned air passing through the dead cylinder can overheat the catalytic converter. The reduced power may make the vehicle unsafe in traffic situations requiring quick acceleration.
Common Causes
30%
Broken or severed wire in the cylinder #2 injector harness
25%
Disconnected, backed-out, or damaged pin in the cylinder #2 injector connector
25%
Burned-out (open) fuel injector coil winding on cylinder #2
15%
Severely corroded connector terminal creating an effective open circuit
5%
ECM driver output open-circuit failure for cylinder #2
Diagnostic Steps
1
Check for cylinder #2 misfire code (P0302) and related injector codes (P1262, P1267) to understand the complete picture.
2
Disconnect the cylinder #2 injector connector and inspect both the sensor side and harness side for backed-out pins, broken terminal retention tabs, or severe corrosion.
3
Measure the fuel injector coil resistance with a multimeter. An open reading (OL or infinity) indicates a burned-out injector. Normal resistance is typically 11-18 ohms for high-impedance injectors.
4
If the injector resistance is within specification, perform a continuity check on each wire from the injector connector pins back to the corresponding ECM connector pins to locate the open circuit.
5
Repair any broken wires, replace damaged connectors, or replace the fuel injector if the coil is open. Clear codes and verify the repair with a test drive.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM has detected a high-to-low side open circuit condition in the cylinder #2 fuel injector driver circuit. An open circuit means there is a complete break in the electrical path to the cylinder #2 injector — either the power feed wire or the ECM control wire is broken or disconnected. The injec...
The most common cause of P1277 (Cylinder #2 High To Low Side Open) is: Broken or severed wire in the cylinder #2 injector harness
Typical repair costs for P1277 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A completely non-functional cylinder #2 injector causes a persistent dead misfire with rough running, vibration, and substantial power loss. Unburned air passing through the dead cylinder can overheat the catalytic converter. The reduced power may make the vehicle unsafe in traffic situations requiring quick acceleration.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1277 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Manufacturer
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