Transmission Range Sensor Circuit malfunction (PRNDL Input)
Your transmission range sensor, which tells the engine what gear you've selected (Park, Reverse, Neutral, Drive, Low), is sending a bad signal or disconnected. It's like the engine can't read which gear you're trying to use.
The ECM monitors voltage from the transmission range sensor (PRNDL switch) to determine selected gear position. The sensor uses a series of electrical contacts that complete different voltage circuits for each position. If voltage falls outside expected ranges or doesn't match gear selector movement, a malfunction is detected.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| PRNDL Voltage Signal | 0.5V-4.5V (varies by position P/R/N/D/L) | Open circuit, short to ground, or erratic voltage changes |
| Sensor Response Time | Immediate voltage change with gear selection | Delayed or no voltage transition detected |
Code P0706 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, P0706 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.