Diagnostic Lamp Driver Fault
The check engine light circuit itself is broken—the ECU can't control the dashboard warning lamp properly. It's like a light switch that doesn't work even though the bulb is fine.
The ECU monitors the diagnostic lamp driver circuit output voltage and current draw to ensure it can properly control the check engine light. It detects open circuits, shorts, or excessive resistance in the lamp driver circuit. When the ECU cannot achieve proper control voltage or senses abnormal current conditions, it sets this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Lamp driver output voltage | 12V capable when activated | Below threshold or no response |
| Circuit current draw | 100-500mA range | Open circuit or excessive draw detected |
Code P1614 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, P1614 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.