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P0708 — Transmission Range Sensor Circuit High

Generic OBD-II · all makesPowertrain (engine & transmission)

P0708 signals that the transmission range sensor is sending a voltage reading higher than the expected range to the vehicle's control module. This sensor communicates the gear selector position, and an abnormally high signal usually points to a short, sensor failure, or wiring issue.

Symptoms

What causes it — most likely first

1. Faulty transmission range sensor

The sensor itself can develop an internal short or fail, causing it to output a voltage that is consistently high.

2. Damaged wiring or connector

Corroded, broken, or loose wires and connectors between the sensor and the control module can create a high‑voltage condition.

3. Improper shift linkage adjustment

If the shift linkage is out of specification, the sensor may never see the correct position and can report an abnormal voltage.

4. Transmission control module fault

A rare internal failure in the module can misinterpret sensor signals, but this is less common than sensor or wiring issues.

5. Internal transmission mechanical problem

Severe internal damage that affects the sensor's mounting or movement can cause abnormal readings, though it is uncommon.

How it's diagnosed

  1. Check transmission fluid level and condition, topping off if low.
  2. Inspect the sensor wiring harness and connectors for corrosion, damage, or loose pins.
  3. Measure the sensor's resistance and voltage with a multimeter while moving the shifter through all positions.
  4. Verify the shift linkage or cable adjustment according to the vehicle's service specifications.
  5. Clear the code and re‑scan; if it returns, test the transmission control module communication and consider sensor replacement.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Can I fix P0708 by simply replacing the PCM?

No. The PCM is rarely the cause; most often the issue is a faulty sensor, wiring problem, or misadjusted linkage.

Will low transmission fluid trigger P0708?

Low fluid can cause shifting problems but does not directly generate a high‑circuit reading from the range sensor.

Is this code serious for vehicle operation?

It can cause drivability issues such as limited gear selection or limp mode, so it should be addressed promptly but is not an immediate safety hazard.