Code
P1705
LEXUS
P — Powertrain
Direct Clutch Speed Circuit Fault
Views:
UK: 24
EN: 35
RU: 35
AI status
Completed
Completed
100%
Causes
- Open or short in direct clutch speed sensor wiring
- Faulty direct clutch speed sensor (Hall or VR type)
- Poor connector contact or corrosion at sensor/TCM
- Faulty TCM (signal input or driver circuit)
- Missing or unstable reference voltage/ground
- Mechanical damage to tone ring/reluctor or magnetic interference
Symptoms
- MIL (check engine/transmission light) illuminated
- Transmission may shift harshly, slip, or enter limp/limitation mode
- Incorrect gear selection or late/erratic shift timing
- Reduced drivability or limited top gear
- Intermittent loss of speed reading for the direct clutch
What to check
- Scan for stored and pending codes; record freeze-frame and live data
- Visual inspection of sensor, connector, and harness for damage or corrosion
- Back-probe sensor connector and observe signal while cranking/rolling
- Check reference voltage and ground at sensor connector
- Wiggle harness while observing live data for intermittent changes
- Inspect reluctor/tone ring or sensor mounting for physical damage or debris
Signal parameters
- Hall-effect sensor: square/pulse signal (0–5 V swing) referenced to a 5 V supply; pulse frequency proportional to clutch speed
- VR (variable reluctance) sensor: AC sine/alternating signal; amplitude and frequency increase with speed and requires proper bias/ground
- Expected behavior: clean, continuous pulses/frequency proportional to rotation; no intermittent drops to 0 V or short to battery/ground
Diagnostic algorithm
- Retrieve freeze-frame and related transmission codes; note conditions when code set (temp, speed, gear).
- Visually inspect connector and harness at the direct clutch speed sensor for corrosion, loose pins, or damage.
- With ignition on (or engine cranking per manufacturer procedure), back-probe the sensor connector: verify reference voltage (if Hall type), signal waveform, and good ground.
- If VR type, check for AC signal while rotating the clutch/transmission input (use scope or AC voltmeter).
- Perform continuity and resistance checks from the sensor connector to the TCM connector to detect opens or shorts; check resistance to ground/power to find unintended shorts.
- Wiggle the wiring harness and connectors while monitoring live data to reproduce intermittent faults.
- Inspect the tone ring/reluctor and sensor air gap; repair or replace if damaged or contaminated.
- If wiring and sensor test good, inspect TCM connector and grounds; consult wiring diagram and bench-test or substitute known-good TCM if suspect.
- After repairs, clear codes and take a road test or dyno test to confirm stable sensor readings and that P1705 does not return.
Likely causes
- Corroded or disconnected connector at the clutch speed sensor
- Broken wire or short-to-ground/power in the sensor harness
- Failed speed sensor (common wear or heat damage)
- Bad ground or low reference voltage from TCM
- Damaged reluctor/tone ring on clutch or transmission input
Fault status
Status
Direct clutch speed sensor/circuit abnormal — check sensor, wiring, connectors, and TCM input
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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