Electric Current Circuit Malfunction
Your engine's computer detected an electrical problem in a circuit that controls a specific function, like it found a broken wire or loose connection. It's similar to a light switch that won't work because the wiring is faulty.
The ECU monitors voltage and current flow in various control circuits, comparing actual readings against expected baselines. When current draw is too high, too low, or absent, the ECU triggers this fault code indicating a circuit malfunction.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Circuit Current Draw | Within expected operating range for the circuit | Excessive current, insufficient current, or open circuit detected |
| Circuit Voltage | 10.5V to 14.5V typical operating range | Voltage out of specification or circuit dropout |
Code P1520 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, P1520 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.