P0705 Code: Transmission Range Sensor Circuit Malfunction (PRNDL Input)

What the P0705 code means

The computer needs to know where the gear selector is to decide several things at once: whether to allow the engine to start, which gear to engage, when to turn on the reverse lights and what to show on the dash.

The transmission range sensor takes care of that. It is also called the neutral safety switch or inhibitor switch. It usually mounts on the outside of the transmission, on the shift lever shaft, and it works with a set of contacts or a potentiometer that gives a different value in each position.

The P0705 code is stored when that signal is missing, inconsistent or matches two positions at once. The last case is more common than it sounds: a sensor that is out of adjustment can sit between two positions and send both signals at the same time.

The typical result is a vehicle that will not start in park but will start in neutral, or the other way around, because the system only allows starting when it clearly recognizes one of those two positions.

A useful point before you take anything apart: check whether the vehicle has a shift lock feature, the one that keeps you from taking the lever out of park without pressing the brake. If that does not respond either, the problem may be in the brake pedal switch and not in the range sensor, because both take part in the same chain of permissions.

P0705 code symptoms

• The engine will not start in park but starts in neutral, or the other way around.
• The dash does not show the selected gear, or shows dashes.
• Check engine light and transmission warning light on.
• Harsh shifts, late shifts or no shifts at all.
• The reverse lights do not come on when you select reverse.
• Transmission in limp mode with a single gear.
• Cruise control does not engage.
• The lever will not come out of park even when you press the brake.

Likely causes of the P0705 code

1. Range sensor out of adjustment, sitting between two positions and sending contradictory signals.
2. Sensor failed from worn internal contacts.
3. Water or dirt getting into the sensor, because it sits exposed on the outside of the transmission.
4. Corroded connector or one with backed-out pins.
5. Damaged wiring along its run to the transmission.
6. Shift linkage or cable out of adjustment, so the shaft does not reach the exact position.
7. Blown fuse in the circuit.
8. Failed transmission module. The last possibility.
9. Faulty brake pedal switch, which takes part in the same chain of permissions as the range sensor.

How to diagnose the P0705 code step by step

1. Watch the position the scan tool reports as you move the lever through every position. It should match in each one, with no jumps and no double positions.
2. Check whether the engine starts in one position and not in another. That points straight at the sensor adjustment.
3. Verify the sensor adjustment. Many let you loosen the bolts and rotate the sensor slightly to center the neutral position.
4. Inspect the connector for corrosion, moisture and backed-out pins.
5. Measure the continuity or resistance of the sensor in each position, depending on the type.
6. Check the shift linkage or cable. A mechanical misadjustment produces the same symptom without a bad sensor.
7. Check the fuse and the power supply to the circuit.
8. Check whether the reverse lights work. They share the circuit, so a failure there confirms the diagnosis.
9. Check whether the lever comes out of park when you press the brake. If it does not, also check the brake pedal switch, which is part of the same chain.

How to fix the P0705 code

• Adjust the sensor, centering it on the neutral position following the manufacturer procedure. It is the most common repair and needs no parts.
• Replace the sensor if its internal contacts are worn or water got in.
• Adjust the shift linkage or cable if the misadjustment is mechanical.
• Clean or replace the corroded connector and protect it with dielectric grease.
• Repair damaged wiring, following the original routing.
• Replace the fuse and find out why it blew.
• Replace the brake pedal switch if the shift lock does not respond either, before you work on the range sensor.

After the adjustment, check that the reported position matches in every gear and that the engine starts in park and in neutral. Then clear the P0705 code and confirm it does not return.

Technical reference data

• The sensor must give a different, unambiguous value in each lever position.
• Starting is only allowed in park and in neutral: it is a safety function.
• The reverse lights usually share the circuit with this sensor.
• Many sensors can be adjusted by rotating them on their shaft with the bolts loosened.
• A misadjustment can make the sensor report two positions at once.
• The brake pedal switch takes part in the permission chain together with the range sensor.

Brand-specific notes

Before you order the sensor, try adjusting it. On many vehicles it is enough to loosen its bolts, center the neutral position with the lever in neutral and tighten them again. It is the most common fix for this code and it costs nothing in parts.

Check the reverse lights too. If they do not work either, you confirm that the circuit is involved. If they work normally, the problem may be closer to the module than to the sensor.

Frequently asked questions about P0705