Error Code P1706 is defined as Transmission Range Control Switch Circuit Open.

This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, especially vehicles made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs vary from one make and model to another.


When the shift position is P or N (Park/Neutral Position or PNP) switch is turned On. The PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) detects the position because the continuity of the line (the On signal) exists.

The PNP switch assembly also indicates a transmission range switch to detect shift lever position.

Error Code P1706 is detected when the signal of PNP switch is not changed in the process of engine start or driving.

Common Symptoms

As with other error codes, this code activates the Check Engine light and registers the code to the vehicle’s system.

Possible Causes

There are a couple of common possible causes of this error code; signal line open or switch failure. In other cases, it could also be due to:

  • Faulty Park/Neutral switch
  • Misadjusted Park/Neutral switch
  • Open or shorted Park/Neutral switch harness
  • Poor electrical connection in Park/Neutral switch circuit

How to Check

As with many error codes, diagnosis for this code starts with using an AutoHex II scan tool.

The malfunction is detected when the Engine is started, the voltage from IG1 is more than 10.5V, and the input voltage from VBU to TCM is less than 6V for at least 2 seconds.

How to Fix

Common repairs for this code include:

  • Replacement of Park/Neutral switch
  • Repair or replacement of park/neutral switch harness
  • Repair or replacement of poor electrical connection in park/neutral switch harness circuit

Fixing this error code is relatively easy. Simply jack up your vehicle and stick an axle stand in place for safety. Then, undo the wiring plug, as well as the sensor and replace with a new one. Ready your new sensor or put your thumb over the top of the hole to keep the oil in when you take the sensor out.

Also, make sure you check the plug and wiring to make sure they’re not corroded or wet.