P0708: Transmission Range Sensor Circuit High (Meaning, Causes, Fixes)
What P0708 means
The transmission range sensor (TRS), also called the inhibitor switch, PRNDL input or neutral safety switch, tells the transmission control module (TCM) and powertrain control module (PCM) whether the transmission is in park, reverse, neutral, drive or a lower gear. RepairPal says it is attached directly to the transmission's manual valve. OBD-Codes.com explains that the sensor receives a 12-volt signal from the ignition switch and sends a signal back to the PCM/TCM for the selected shifter position. P0708 is set if the module receives signals indicating two different gear positions at the same time for more than 30 seconds. It is a generic OBD-II code, though repair steps vary by make and model. The sources describe it differently: OBD-Codes.com ties P0708 to conflicting gear-position signals, while RepairPal says the PCM sets it when the sensor input is erratic or irrational (the same general wording it uses for the other range sensor codes) and defines it as a circuit high input. On the warning light, OBD-Codes.com calls P0708 a type "B" code that turns on the check engine light only after the fault is seen on two consecutive key cycles, and says the transmission then goes into limp mode, typically starting off in third gear; RepairPal simply lists the check engine light as a symptom. RepairPal also lists a defective manual valve or linkage and dirty transmission fluid as possible causes, which OBD-Codes.com does not mention. Related codes are P0705 (circuit malfunction), P0706 (range/performance), P0707 (circuit low) and P0709 (intermittent).
Severity: can I keep driving?
Stop and fix promptly
Get it fixed right away. OBD-Codes.com says the transmission is commanded into fail-safe (limp-home) mode, that continuing to drive could cause severe transmission damage, and recommends repairing it immediately to avoid costly internal repairs. RepairPal rates P0708 Urgent. Because the range sensor usually includes the park/neutral safety switch, set the parking brake and keep your foot on the brake whenever you start the engine until it's fixed.
Common symptoms
- Check engine light on; OBD-Codes.com says it lights after the fault is detected on two key cycles in a row (both sources)
- Obvious lack of power pulling away from a stop because the transmission starts in third gear in limp-home mode (OBD-Codes.com)
- Vehicle may not shift properly or may not go into gear (RepairPal)
- Decrease in fuel economy (RepairPal)
- In unusual cases, no noticeable symptoms (RepairPal)
Likely causes
Roughly most to least common, based on the sources below. Your vehicle may differ.
- Faulty transmission range sensor; OBD-Codes.com says this is one of the most common causes (both sources)
- Misadjusted transmission shift cable or linkage; OBD-Codes.com names this among the most common causes (both sources mention linkage)
- Damaged range sensor wiring or connector (both sources)
- Misadjusted range sensor (OBD-Codes.com)
- Defective manual valve, or dirty transmission fluid restricting hydraulic passages (RepairPal)
- Rarely, PCM or TCM failure; OBD-Codes.com says its author has never seen a module cause a range sensor code, though a module can be damaged by a short in the sensor circuit
Diagnostic steps you can do
Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.
- Read all stored codes before clearing anything, since P0708 can appear alongside other transmission codes.
- Set the parking brake and block the wheels before testing anything near the shifter or transmission.
- Check that the shift cable or linkage is properly adjusted so the shifter position matches the transmission's actual gear.
- Inspect the range sensor connector and harness for damage, corrosion or oil contamination and repair anything you find.
- OBD-Codes.com's voltage test: with the key on and engine off, back-probe each signal circuit at the connected sensor while a helper moves the shifter through each position. Each signal circuit should have voltage in one position only; voltage on any circuit in more than one position points to a faulty range sensor. A scan tool makes this easier.
- If the PCM or TCM is ever replaced, find and fix any short in the sensor circuit first so the new module isn't damaged the same way, as OBD-Codes.com warns.
- Follow your vehicle's service manual for sensor location, wiring diagram and adjustment procedure, since these vary by make.
Typical fixes
- Adjust the shift cable or linkage
- Readjust a misadjusted transmission range sensor
- Replace a faulty transmission range sensor
- Repair damaged range sensor wiring or connectors
- Service dirty transmission fluid or repair the manual valve or linkage if diagnosis points there (RepairPal)
- Replace or reprogram the PCM or TCM only after everything else checks out
Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.
🛠 When to call a pro
- The transmission is stuck in limp mode or won't go into gear
- The engine starts with the shifter out of park or neutral
- You've checked the linkage, wiring and sensor and the code comes back
- You suspect an internal problem such as the manual valve
Where to buy
Plain search links. Always match parts to your exact year, make, model and engine.
FAQs
Is P0708 serious?
Yes. OBD-Codes.com says the transmission goes into limp mode and continuing to drive could cause severe transmission damage, so it recommends repairing it immediately. RepairPal rates it Urgent.
What's the difference between P0707 and P0708?
P0707 means the computer sees low or no voltage coming back from the range sensor, usually an open circuit, a short or a blown fuse. OBD-Codes.com says P0708 is set when the sensor reports two different gear positions at the same time for more than 30 seconds, most often from a bad sensor or a misadjusted shift linkage.
Why does my car start off in third gear with P0708?
OBD-Codes.com explains that once P0708 sets twice in a row, the transmission is commanded into fail-safe or limp-home mode, which typically means starting off in third gear and feeling a big loss of power from a stop.
How much does it cost to fix P0708?
Neither source gives a repair cost. It depends on whether the fix is a linkage adjustment, wiring, a new sensor or something internal, so get a diagnosis or a written estimate first.
Sources
Last reviewed 2026-10-25. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.