Sensor Power Supply Malfunction
Your engine's computer detected that a sensor isn't receiving proper electrical power. Think of it like a lamp that won't turn on because the power cord is disconnected or damaged.
The ECM monitors the 5V reference voltage supplied to sensors and detects if the supply drops below acceptable thresholds. When voltage is insufficient, the sensor signal becomes unreliable and the ECM cannot trust the data.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Reference Voltage | 4.8V - 5.2V | Below 4.5V or no signal detected |
| Sensor Signal Ground | 0.1V or less | Above 0.5V (poor ground connection) |
Code P1245 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, P1245 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.