Error Code P0707 is defined as Transmission Range Sensor “A” Circuit Low. This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, especially those made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.
This code refers to the transmission control system, and a type “C” code, which means it doesn’t cause the Check Engine light to light up, but may cause the overdrive (O/D) or D4 indicator to blink. Only emission-related code activates the Check Engine light.
The voltage signal is sent to the transmission range sensor. It changes or reroutes it according to the position of the gear shifter. This code specifically means there’s a low condition in the circuit. It refers to a low or no voltage signal returning to the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes). The PCM looks for a specific voltage range in the transmission range sensor, and when the voltage input is low, then it sets this code. When diagnosing this code, it’s best to refer to a diagram.
There is a wide range of symptoms for this code, including:
- No start condition due to an internal transmission range sensor’s park/neutral switch
- Erratic shifting
- Start in gear
- Lack of power caused by “limp mode”
- Increase in fuel consumption
- Failed transmission range sensor
- Failed park/neutral position switch
- Open or short in wiring harness
- Poor electrical connection
- Misadjusted transmission park/neutral position switch
How to Check
To better diagnose this code, we need to understand two things: Open and Short circuit.
Open Circuit – This is when a circuit doesn’t make a complete loop from negative to positive of the battery. I.e., a light bulb will not work if the filament is broken in half. The circuit will be open at the broken filament.
Short Circuit – This is when the negative of the battery comes in contact with the positive, without some load between them. There has to be a component (light, senor, motor, etc.) in the circuit. It’s like dropping a wrench on top of the car battery, and it touches both terminals, causing a spark. This is called direct short.
Open circuit will cause low voltage to the PCM. A short circuit at the same points can cause a blown fuse and low voltage at the PCM. Both will trigger the Error Code P0707.
To diagnose this code:
Check for any current codes, pending, and/or history using the scan tool
Clear the codes and then take the vehicle for a test drive to confirm the fault
Conduct a visual inspection for the misaligned shifter linkages, broken wirings, or worn and damaged components, and transmission fluid level and condition
Monitor the transmission’s range sensor operating using the scan tool
Check the transmission range sensor voltage using a multimeter
How to Fix
Depending on the diagnosis, common repairs for this code include:
- Replacement of transmission range switch
- Replacement of transmission fluid
- Repair or replacement of open or short in wiring harness
- Repair or replacement of broken electrical connections
- Repair or replacement of park/neutral position switch
Error Code P0707 will cause the vehicle to no start since the PCM thinks the transmission is in the wrong gear. For some cases, the vehicle will still run, but shifts poorly. Both cases are considered a serious problem.
The most common mistake in diagnosing this code is overlooking the condition of the transmission fluid or misadjusted position sensor. Sometimes, people also jump on replacing components that are working fine.