P0705 Code: Transmission Range Sensor A Circuit (PRNDL Input)
The computer can't make sense of the gear selector position signal – P, R, N, D may be misread.
At a glance
Severity: Moderate
- Meaning
- Transmission Range Sensor A Circuit (PRNDL Input)
- System
- Transmission · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $60–$750
- DIY difficulty
- Moderate
The transmission range sensor – also called the neutral safety switch, PRNDL switch or MLP sensor – tells the computers which position the shift lever is in. Most versions send a pattern of three or four on/off circuits, and each lever position has its own valid combination. P0705 sets when the module sees a combination that belongs to no position, or a signal that drops out while you drive. Because the same sensor enables the starter, the reverse lights and the gear display, the symptoms are often electrical rather than shifting-related. The sensor sits on the outside of the case at the shift shaft on many vehicles, but some designs mount it inside the transmission.
Can I keep driving? If the engine starts and the display shows the right gear, you can drive carefully to a shop. Always set the parking brake when parked – a module that misreads Park may not stop the engine from starting or the lever from moving as expected, and don't rely on remote start until it's fixed.
How to read P0705
- P Powertrain
- 0 Generic (SAE)
- 7 Transmission
- 05 Specific fault
Symptoms
- Engine won't crank in Park but starts in Neutral (or the other way round)
- Gear indicator on the dash blank, flashing or showing the wrong letter
- Reverse lights stay off in Reverse or come on in other positions
- Transmission stuck in a single gear or engages harshly
- Key won't come out of the ignition or push-button won't switch off in Park
- Check engine light, often with P0700
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Worn or failed range sensor (internal contacts or electronics)
- Water or corrosion in the sensor connector, which sits low in road spray
- Damaged harness near the shift shaft, exhaust or crossmember
- Sensor loose or misadjusted after transmission or cable work
- Fused or blown circuit feeding the sensor, or a poor ground
- Transmission or engine module input fault
Diagnosis step by step
Watch the range PID in every position
With the key on and foot on the brake, move the lever slowly through P, R, N, D and the lower ranges while watching the transmission range reading on a scan tool. A position that shows 'invalid', 'between' or a wrong letter tells you where the signal breaks down.
Tools: OBD-II scanner
Check starter and reverse-light behavior
Note whether the engine cranks in Park and Neutral only, and whether the reverse lights follow the lever. If both behave correctly but the display is wrong, the fault may be in the circuit to one module only.
Tools: Flashlight
Inspect the sensor and its connector
Find the sensor at the shift shaft on the side of the transmission (on some units it is inside the pan). Unplug it and look for green corrosion, water, bent pins or a cracked housing; clean and dry any contamination.
Tools: Flashlight, Screwdriver
Test each circuit against the chart
Back-probe the signal wires and move the lever. Each circuit should switch cleanly between about 0 V and battery or reference voltage according to the position chart in the service information; a circuit that never changes or sits halfway points to the sensor or that wire.
Tools: Multimeter
Wiggle-test the harness
With the meter or scan tool connected, flex the harness near the transmission mount, exhaust and shift cable bracket. A reading that flickers while you move the wires means a broken conductor or chafed insulation.
Tools: Multimeter, OBD-II scanner
Replace and set the sensor correctly
A new sensor must be aligned to the shift shaft, often with the lever in Neutral and an alignment pin or gauge. After installation, confirm every position on the scan tool and verify the engine only starts in Park and Neutral.
Tools: Torque wrench, OBD-II scanner
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Clean and seal the sensor connector | Yes | $60–$150 |
| Repair chafed range sensor wiring | No | $120–$350 |
| Replace external range sensor and adjust | Yes | $180–$450 |
| Replace internal range switch (pan removal and fluid) | No | $350–$750 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Chevrolet
GM rear-wheel-drive automatics such as the 4L60E family use an internal mode switch mounted inside the transmission on the manual shaft; on the 6L80 family it is part of the internal control module assembly. Crank/no-crank problems and wrong gear displays with range codes are well known on Silverado and Tahoe models.
Ford
Many Ford automatics use an external range sensor on the driver's side of the case, called the MLP or DTR sensor. It is exposed to water and salt, and connector corrosion is a frequent reason for range codes and no-crank complaints on trucks and SUVs.
Field data
| Ford | 12 | ||
|---|---|---|---|
| Nissan | 7 | Versa, Versa Note | |
| Kia | 2 | Optima, Sedona |
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
P0705 turns on the check engine light, so the car fails an OBD-based smog or emissions inspection until the range sensor fault is fixed and the code stays off.
Frequently asked questions
Is the transmission range sensor the same as the neutral safety switch?
Mostly, yes. Older cars had a simple neutral safety switch that only enabled the starter; modern range sensors also report every lever position to the transmission computer and run the reverse lights and gear display.
Can P0705 leave me stranded?
It can. If the module never sees a valid Park or Neutral signal, the starter won't engage. Trying Neutral, or wiggling the lever slightly in Park while turning the key, sometimes gets it started – a strong sign the sensor or its adjustment is at fault.
Why did P0705 appear after a car wash or heavy rain?
External range sensors sit low on the transmission, close to where water splashes. Water in a worn connector seal can short the switch circuits temporarily; the code may clear once it dries, but corrosion keeps coming back unless the connector is cleaned and sealed.
Do I need to adjust a new range sensor?
On most external sensors, yes. It must line up exactly with the shift shaft position, otherwise the module sees a position between two gears and sets a new range code, usually P0706.