Transmission 4-Wheel Drive Low Indicator Open Circuit
The transmission's 4-wheel drive low range indicator light circuit is broken or disconnected, like a light switch with a severed wire. The ECU detects no signal when it tries to turn on the 4WD low indicator.
The ECU monitors voltage on the 4WD low indicator circuit, expecting a valid signal when 4WD low range is commanded. An open circuit prevents current flow, causing the ECU to detect zero or out-of-range voltage.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Indicator circuit voltage | 12V when active / 0V when inactive | No voltage change or stuck at 0V (open circuit detected) |
| Circuit continuity resistance | Less than 1 ohm (complete circuit) | Infinite or very high resistance (open/broken) |
Code P1814 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, P1814 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.