P0705

Transmission Range Sensor A Circuit malfunction (PRNDL Input)

P0705 is a generic OBD-II powertrain diagnostic trouble code: Transmission Range Sensor A Circuit malfunction (PRNDL Input). It is logged by the engine control unit when the trans monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0705
Group
Powertrain
System
Trans
Severity
Warning (MIL on, possible limp mode)
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What P0705 means

DTC P0705 is set when the Transmission Control Module (TCM) or Powertrain Control Module (PCM) detects an invalid or implausible signal from the Transmission Range (TR) sensor, also known as the Manual Lever Position (MLP) sensor or Park/Neutral Position (PNP) switch. This sensor communicates the driver's selected gear range — Park, Reverse, Neutral, Drive, or a manual range — by generating a unique combination of switch states on four input circuits. When the PCM/TCM reads a pattern that does not correspond to any recognised gear position, or receives no valid signal at all, it stores P0705 and illuminates the MIL.

The TR sensor plays a critical safety role beyond gear selection feedback: it prevents the starter motor from cranking in any position other than Park or Neutral, enables the correct shift-schedule logic in Drive, restricts upshifts in manual ranges, and activates the reverse lights. A malfunctioning sensor can therefore affect starting ability, shift quality, and lighting — not just trigger a warning lamp. Because the TCM may be unable to determine the correct gear, many vehicles will default to a fixed gear or reduced-functionality limp mode to protect the transmission from inappropriate shift commands.

P0705 is an SAE generic (J1979) code that applies to any OBD-II compliant automatic-transmission vehicle, though the physical sensor location, connector pinout, and adjustment procedure vary by manufacturer. On most vehicles the TR sensor is mounted on the transmission case at the manual shaft, and mis-adjustment after a service or repair is one of the most common non-electrical root causes.

Common causes

Most-frequently reported root causes when P0705 is logged.

  • 1
    Faulty or failed Transmission Range (TR) / Manual Lever Position (MLP) sensor
  • 2
    Mis-adjusted or out-of-position TR sensor on the transmission manual shaft
  • 3
    Open circuit, short to ground, or short to voltage in the TR sensor wiring harness
  • 4
    Corroded, damaged, or loose connector pins at the TR sensor or TCM
  • 5
    Water intrusion into the TR sensor connector causing intermittent signal loss
  • 6
    Defective TCM/PCM (rare — only after wiring and sensor are confirmed good)
  • 7
    Mechanical damage to the transmission manual linkage affecting sensor position
  • 8
    Chafed or broken wiring routed near hot or moving components

Symptoms drivers notice

MIL (Check Engine / Service Engine Soon) illuminated
Gear selector position indicator on instrument cluster shows incorrect or no gear
Transmission enters limp mode (fixed gear, usually 3rd or 2nd, with limited engagement)
Vehicle will not crank or start (starter inhibit active in wrong state)
Reverse lights inoperative or illuminated in the wrong gear
Harsh, delayed, or erratic gear shifts due to TCM operating without valid range input

How to diagnose P0705

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all stored DTCs and freeze-frame data; note any related transmission (P07xx), chassis (Cxxx), or module communication (Uxxx) codes that may point to a wiring or power supply fault
  2. 2
    Inspect the TR sensor wiring harness and connector for visible damage, chafing, corrosion, or moisture; wiggle the connector while monitoring live TR sensor data on a scan tool to reveal intermittent faults
  3. 3
    With the ignition on (engine off), use a scan tool to monitor the TR sensor input states in each selector position — Park, Reverse, Neutral, Drive, and manual ranges — and verify the pattern matches the expected values for the vehicle
  4. 4
    Verify TR sensor adjustment: with the selector in Neutral, check that the sensor is aligned per manufacturer specification (typically a slot or pin alignment mark on the sensor body); re-adjust if necessary and recheck sensor pattern
  5. 5
    Perform a pin-out voltage or resistance check at the TR sensor connector against the factory wiring diagram; look for open circuits, shorts to ground, or short-to-power conditions on each of the four sensor signal wires
  6. 6
    If wiring and adjustment are confirmed good, test the TR sensor in isolation (bench test or substitute with a known-good unit) to determine whether the sensor itself has failed internally
  7. 7
    Clear codes after repairs, perform a complete drive cycle through all gear positions, and confirm P0705 does not return before releasing the vehicle

Related powertrain codes

Frequently asked questions

Can I drive with a P0705 code?

It depends on how the vehicle responds. If the transmission has entered limp mode you can drive short distances at low speed to reach a workshop, but extended driving risks overheating the transmission. If the vehicle will not start due to the starter-inhibit circuit, it cannot be driven at all. Either way, prompt diagnosis and repair are strongly advised.

Is P0705 always caused by a bad sensor?

Not always. The sensor itself is one possibility, but mis-adjustment after a service, a damaged wiring harness, or corroded connector pins are just as common — and cheaper to fix. Always inspect wiring and check sensor alignment before condemning the sensor.

Will P0705 cause the car to not start?

Yes, it can. The TR sensor is part of the neutral safety / starter-inhibit circuit. If the TCM receives no valid signal or an invalid pattern, it may prevent the starter relay from engaging because it cannot confirm the transmission is in Park or Neutral.

How much does it cost to fix P0705?

Repair cost varies widely. Sensor adjustment (if just out of alignment) may cost under $100 in labour. Replacing the TR/MLP sensor typically runs $150–$400 depending on the vehicle and labour rate. Wiring repairs vary based on severity. TCM replacement is the most expensive scenario, generally $500–$1,500 or more including programming.

Disabling P0705 in software

RaceTune can permanently disable P0705 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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