P0705 - Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input)
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input) (P0705).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input) – Coil Resistance | Resistance (Ω) | 3 - 30 Ω (typical) | Connector disconnected at 20°C |
| Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input) – Duty Cycle | PWM (%) | 5 - 95 % (modulates with target) | Engine running, actuator in control |
| Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input) – Supply Voltage | Voltage (V) | 11.8 - 14.4 V | Ignition ON at connector |
Connector disconnected at 20°C
Engine running, actuator in control
Ignition ON at connector
Oscilloscope Waveform Analysis
2 ms/div, 20 V/divPossible Causes
Mechanical sticking or debris/carbon contamination jamming Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input)
Channel A:Verify dedicated wiring pins and signal pair for circuit A against the schematic.
Chafed or pinched wiring harness along the signal path to Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input)
Internal mechanical wear or carbon deposits inside Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input)
Defective internal output driver or reference circuit in the control module for Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input)
Symptoms
Recommended Solution
Compare signal voltage and resistance between circuit A and companion circuit B at module connector.
Command the actuator via scan-tool output tests to determine if the solenoid can overcome the return spring.
Verify loaded supply voltage and harness terminal pins at Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input).
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Transmission Range Sensor (PRNDL) 'A' Circuit (PRNDL Input).
Check supply and the low-side driver at the ECM connector. Replace the actuator or repair the circuit based on the readings.
Mechanic's Tip
Use the scan-tool output test with the scope on the control side at the same time. If duty changes but the actuator does not move, the valve is stuck — not the electrical fault you were chasing.