Sensor Power Supply Low Input
Your engine's computer detected that a sensor isn't receiving enough electrical power to operate properly. It's like trying to run a device with weak batteries—it can't function correctly.
The ECU monitors the power supply voltage delivered to oxygen sensors, MAF sensors, or other critical sensors. When voltage drops below the minimum threshold required for accurate signal output, the ECU triggers this fault. The sensor cannot generate reliable data at low voltage levels.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Supply Voltage | 4.5V - 5.5V | Below 4.0V |
| Signal Quality | Valid signal output | Erratic or missing signal |
Code P1246 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, P1246 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.