P0707–P2802 Transmission Range Sensor A Circuit Low

Which code is which

Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.

The definition

P0707: Transmission Range Sensor A Circuit Low.

P0707 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.

What to check first

Cheapest and fastest checks first:

1. Unplug the sensor. If the reading jumps to full scale, the wiring is fine and the sensor has failed low.
2. Check the sensor's 5V supply and its earth before condemning the sensor itself.

What actually causes this on a VAG

The control unit is seeing the selector position signal wire sitting low, at or near earth, when the current lever position should not be producing that. On VAG automatics this input is a set of wires from either a switch on the gearbox or a position sensor inside it, so a single wire held down is enough to trigger it. Typical effects are the car only starting in one lever position, reverse lights that do not work, or the gearbox holding a safe gear. This is an electrical circuit fault rather than a mechanical one - it says a wire or a contact is connected to earth when it should not be, and says nothing at all about the condition of the gears.

Most likely causes, in order

1. Wire chafed to earth near the gearbox. The loom runs across the bellhousing and past heat shields, and a section rubbed through against metal will hold the signal at earth permanently. Look for insulation worn flat, tape that has melted, or a loom that has been pulled tight or re-routed after previous work. Flexing the loom while watching the live position value on a scan tool often makes it show itself.
2. Damp or corrosion in the gearbox connector. Water in the plug conducts between the pins and earth and does exactly the same job as a chafed wire. Unplug it and check for green deposits, white powder, or moisture in the pin cavities, and make sure the seal and the latch are intact. Dry it out and retest before buying anything.
3. Internal short in the switch or position sensor. The switch or sensor can fail with a contact shorted inside. This is the one test worth doing before you spend anything: unplug the component at the gearbox and clear the code. If the complaint changes to an open or high circuit, the short was inside the component and the loom back to the control unit is intact. If the low complaint returns with the component unplugged, the short is in the wiring and a new switch would not have fixed it.

Worth knowing: Do the free half of this job first. Unplugging the connector at the gearbox splits the circuit neatly into two halves and tells you which side the problem is on, which is the difference between a wiring repair and an unnecessary gearbox part. One safety point before you drive it: because this same circuit carries the starter inhibit, a shorted contact can in principle allow the engine to crank with the lever in a driving position. If you find the car will crank anywhere other than P or N, do not use it until it is repaired. Reverse lights that have stopped working are also a roadworthiness failure, not just an inconvenience.

Common questions

What does P0707 mean?

P0707 means Transmission Range Sensor A Circuit Low. The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.

Can I drive with P0707?

The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.

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