Cylinder #1 High To Low Side Open
Cylinder #1's fuel injector circuit has an open connection between the high and low sides, meaning the injector isn't receiving proper electrical signals to spray fuel. Think of it like a broken wire in a lamp—the power can't reach the bulb.
The ECU monitors the voltage and current flow through the fuel injector circuit during opening and closing commands. It detects when the injector fails to respond by measuring the expected voltage drop across the injector coil windings. If the circuit is open, no current flows and the ECU cannot establish the normal electrical signature.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Injector coil resistance | 12-16 ohms | Infinite ohms (open circuit) |
| Injector peak current | 0.8-2.0 amps | 0 amps or no response |
Code P1276 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1276 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.