OBD-II trouble code
P0705: Transmission Range Sensor "A" Circuit (PRNDL Input)
The module cannot read a valid gear selection from the transmission range sensor. Because the same sensor is what permits cranking, this is the code behind the classic "won't start in Park but starts in Neutral" complaint.
Quick facts
- System
- Powertrain
- Category
- Transmission / Shift Control
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $120 – $600
- DIY difficulty
- Intermediate DIY
Browse every code in P0700–P0799, or start from the full code library.
What does P0705 mean?
The transmission range sensor — also sold as the neutral safety switch, PRNDL switch, MLPS or inhibitor switch depending on the make — reports which gear the driver has selected. It is not a conventional two-wire sensor. On most designs it is a multi-position switch riding on the manual shift shaft where it exits the transmission case, and it encodes the selected range as a combination of several parallel circuits that are pulled to ground or left open. Park might be circuits 1 and 3 grounded, Reverse circuits 2 and 3, and so on.
That encoding is the key to understanding P0705. The module is not looking at a voltage and deciding it is out of range — it is looking at a pattern and deciding the pattern is impossible. All circuits open at once, two ranges reported simultaneously, or a combination the lookup table simply does not contain will all set this code. That is why P0705 can appear while the transmission still shifts perfectly: the mechanical linkage is doing its job, the electrical report of it is nonsense.
The consequence that brings most people here is not a shifting problem at all. The same switch is what tells the starter circuit it is safe to crank, and it is what closes the reverse lamp circuit. A vehicle with P0705 very often cranks in Neutral but not in Park, or the other way around, or refuses to crank in any position — which is why this code is treated as a no-start rather than a driveability fault. Expect the transmission to default to a fixed gear or a fail-safe shift pattern as well, because a controller that does not know what range the driver picked will not risk commanding a shift schedule.
Common causes
- Corroded or water-intruded connector at the sensor, which sits low on the case and takes road spray year-round
- Sensor knocked out of index during a transmission, mount or shift-cable replacement — the part is often perfectly good and simply bolted on a few degrees off
- Stretched, loose or misadjusted shift cable holding the manual shaft between detents, which costs nothing but adjustment time to rule out
- Worn or internally failed transmission range sensor / neutral safety switch on a vehicle with no recent work in that area
- Damaged, chafed or rodent-bitten wiring in the harness running along the transmission case
- Open or high-resistance ground for the range sensor circuit
- Failed transmission control module or PCM input driver (uncommon — verify the sensor and wiring first)
Symptoms
- Engine will not crank in Park, but cranks in Neutral (or vice versa)
- Engine will not crank in any gear selector position
- Gear position indicator on the dash is blank, wrong, or shows all positions lit
- Transmission stays in one gear or uses a harsh fail-safe shift pattern
- Reverse lights do not come on, or stay on in other gears
- Check engine light is on
- Vehicle rolls when the selector says Park (linkage-related cases)
Diagnostic steps
- 1.Confirm the basics first: does the gear the driver selected match what the dash indicator shows, and does it match what the scan tool reports as the transmission range PID? Three-way disagreement narrows the fault immediately.
- 2.Watch the range PID on a scan tool while an assistant moves the selector slowly through every position. Do this with the ignition on and the engine OFF, the parking brake set and the wheels chocked — the module reports range with the key on, so there is no reason to have an engine running while someone selects Drive and Reverse. Note exactly which position or transition the reading fails on — a fault in only one range points at the sensor, a fault in all of them points at power, ground or the connector.
- 3.Unplug the sensor connector and inspect it for water, green corrosion or spread terminals. This connector lives low on the transmission case and gets hit with road spray year-round.
- 4.Do not clear the range-sensor ground with a loaded voltage-drop test when the switch is pulled to ground by the module. That circuit carries only the pull-up current, which can be too small for a bad joint to show a useful drop, so the test can pass a ground that is still wrong. With the connector open and the circuit de-energized, measure the resistance of the ground wire, or compare the selected input's voltage at the module with the low level in the service information for this vehicle.
- 5.Verify shift cable adjustment. With the selector in Park, the manual shaft should sit fully in its Park detent, not just close to it.
- 6.If the sensor is replaced, index it correctly. Many designs mount on a slotted plate and must be aligned in Neutral against alignment marks or with a special tool before the bolts are tightened.
Repair cost
$120 – $600
Wiring or a connector repair is the cheap end. An external range sensor bolted to the outside of the case is the middle. A switch inside the valve body is the expensive end, because the pan and the fluid have to come out. Diagnosis earns its place here: a misadjusted cable and a failed sensor produce the same complaint. The figures are a planning span, not a shop quote. Price the sensor or the wiring, then the labor time the service information lists, and remember an external switch and an in-pan switch are different jobs.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with transmission range sensor / neutral safety switch replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.