P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input)
May cause incorrect gear selection, inability to start in correct gear, limp mode, and transmission shifting issues
Overview
P0705 indicates a malfunction in the transmission range sensor circuit (also called the PRNDL or neutral safety switch) responsible for reporting gear position to the PCM/TCM. It can be caused by sensor failure, wiring/connectors issues, or control module faults.
Common Symptoms
- Illuminated check engine light
- Incorrect PRNDL gear display
- Vehicle may only start in neutral or park issues
- Erratic or delayed shifting
- Backup lights not functioning
Most Common Causes
The sensor fails to correctly report gear position to control modules
Open, shorted, or corroded connections interrupt signal
Improperly aligned linkage can send incorrect position signals
Module failure or software issue can misinterpret sensor input
Internal range sensor issues require complex service
Diagnostic Steps
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Connect OBD-II scanner and confirm P0705 with freeze frame dataExpected: P0705 code present and no conflicting codesInterpretation: Confirms code validity
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Visually inspect TRS wiring and connectors for corrosion, damage, or loosenessExpected: No broken wires, clean and tight connectorsInterpretation: Wiring issues may directly cause code
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Check shift linkage adjustment and gear indicator alignmentExpected: Linkage correctly matches gear lever to sensor positionInterpretation: Misalignment can cause erroneous sensor signals
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Test TRS sensor voltage/resistance with multimeter/live data across different gear positionsExpected: Sensor outputs expected values per gearInterpretation: Invalid values suggest sensor failure
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If necessary, test TCM/PCM input circuit for continuity and software faultsExpected: Proper input readings and updated control moduleInterpretation: Faults here indicate control module issues
Repair Solutions
External sensors are simpler and cheaper; internal sensors are more costly and complex
Cost varies with labor and extent of damage
Minor adjustment may resolve sensor signal issues
High cost and complexity; confirm with module testing
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming problem is low transmission fluid without checking sensor circuit
- Confusing P0705 with other transmission codes like P0706–P0709 without confirming sensor output
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