Code
P0715
GWM
P — Powertrain
- Malfunction in the turbine speed sensor circuit
AI status
Completed
Completed
100%
Causes
- Damaged or corroded connector, pins, or wiring to the turbine speed sensor
- Open or short in the sensor signal or ground circuit
- Faulty turbine (input) speed sensor
- Poor sensor reference voltage or ground at the control module
- Intermittent contact from vibration or wiring chafing
- Faulty transmission control module (less common)
Symptoms
- Check Engine Light / transmission warning lamp illuminated
- Incorrect or erratic transmission shift patterns (harsh, delayed, limp mode)
- No vehicle speed vs. engine RPM correlation in transmission behavior
- Stored or pending transmission-related DTCs
- Transmission may fail to engage or shift properly
What to check
- Scan for stored and pending codes; record freeze-frame and live data
- Inspect sensor connector and wiring for corrosion, damage, or pin stretch
- Backprobe signal, reference and ground pins with harness connector connected
- Measure sensor resistance (if specified by manufacturer) and compare to spec
- Check for short to battery or ground using an ohmmeter
- Monitor live turbine/input speed signal while cranking and at various engine/transmission speeds
Signal parameters
- Type: Hall-effect (square wave) or magnetic (AC sine) depending on vehicle design
- Voltage: Hall-type typically 0.0–5.0 V square wave; magnetic sensors produce an AC voltage that increases with speed
- Frequency: proportional to input shaft speed — frequency should increase smoothly with engine/transmission RPM
- Resistance: varies by sensor type and manufacturer — compare to vehicle-specific specification
- Expected behavior: stable, noise-free waveform with no dropouts or erratic pulses
Diagnostic algorithm
- Safety: Park vehicle on level ground, apply parking brake, chock wheels. Use proper PPE.
- Retrieve codes and live data with a capable scan tool. Note turbine/input speed reading at idle and when moving; compare with engine RPM — values should correlate.
- Visually inspect sensor, harness, and connector for damage, corrosion, or fluid intrusion. Repair any obvious damage.
- With ignition on (engine off), backprobe connector: verify reference voltage (if present) and ground continuity to the control module.
- With engine running or transmission driven, measure sensor signal waveform with a lab scope or multimeter (frequency or AC voltage). Verify smooth, proportional signal with RPM/gear changes.
- If signal is missing or erratic, perform continuity and resistance checks between the sensor connector and TCM/ECM harness connector to find opens or shorts. Wiggle harness while monitoring to find intermittent faults.
- If wiring and connectors are good, compare sensor resistance to manufacturer spec; if out of range, replace the turbine speed sensor.
- After repair, clear codes, perform a road test and confirm signal is present and code does not return. If code returns despite good wiring and sensor, consider TCM/ECM input circuit fault and consult manufacturer service information.
- Document findings and any replaced parts. If uncertain, refer to vehicle-specific wiring diagrams and service manual procedures.
Likely causes
- Connector corrosion or loose pin at sensor or PCM/TCM
- Broken or shorted wiring in harness between sensor and control module
- Failed turbine speed sensor
- Contaminated sensor or reluctor wheel (metal debris, oil saturation)
Fault status
Status
The control module detected an abnormal turbine (input) speed sensor signal (open, short, no signal, or implausible waveform). This can cause incorrect shift behavior and may force the transmission into limp mode until the issue is resolved.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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