Transmission Range Sensor Circuit Range/Performance
The Transmission Range Sensor (TRS) communicates the physical position of the shift lever (Park, Reverse, Neutral, Drive) to the engine and transmission control modules. Code P0706 is set when the powertrain control module detects an erratic, irrational, or out-of-range voltage signal from this sensor that does not match expected operating parameters.
This is a high-severity code because the vehicle may fail to start if the computer cannot verify the transmission is in Park or Neutral. It can also cause erratic shifting or force the vehicle into a restricted limp mode, making it unsafe for highway driving.
Common symptoms
- Check Engine Light is illuminated
- Engine fails to crank or start
- Transmission shifts erratically or harshly
- Vehicle enters limp-home mode (stuck in a single gear)
- Dashboard gear indicator (PRNDL) is blank or displays the incorrect gear
Likely causes
- Defective or internally shorted transmission range sensor (neutral safety switch)
- Corroded, damaged, or loose wiring and connectors in the sensor circuit
- Misadjusted or damaged mechanical shift cable or linkage
- Transmission fluid or water contamination inside the sensor connector
- Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM)
What to check before replacing parts
Inspect the transmission range sensor wiring and connector
Look for: Look for broken wires, loose pins, heavy corrosion, or transmission fluid intrusion inside the electrical connector that could distort the signal.
Verify the mechanical shift cable adjustment
Look for: Ensure the shift linkage moves the transmission lever fully into each detent and perfectly matches the gear selected by the driver inside the cabin.
Monitor the TRS data PID using a scan tool
Look for: Observe the gear position data on the scan tool while moving the shifter through all gears. Look for missing, erratic, or incorrect gear states being reported to the computer.
Test the sensor's power and ground circuits
Look for: Use a digital multimeter to verify the sensor is receiving the correct reference voltage (typically 5V or 12V depending on the manufacturer) and has a solid ground with minimal resistance.
Test the sensor signal output voltage
Look for: Back-probe the signal wire with a multimeter while shifting gears. Look for the voltage to step cleanly to the specific values outlined in the manufacturer's service manual for each gear position.
This page explains the generic P0706 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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