P1900

Code

NISSAN P — Powertrain

Turbine Speed Sensor Circuit Intermittent

Brand: NISSAN

Type: P — Powertrain

Views: UK: 30 EN: 60 RU: 48

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Page language: EN

Read and record stored codes and freeze frame data with a scan tool; note any other transmission codes
Inspect sensor connector and wiring for corrosion, breaks, pin damage, paint overspray, or fluid intrusion
Backprobe the sensor connector and observe live turbine speed signal while cranking and driving
Wiggle test harness/connectors while watching live data for intermittent changes
Check power/reference and ground circuits for the sensor for voltage, continuity and high resistance
Compare turbine speed signal to engine RPM, input shaft and vehicle speed for plausibility

Type: May be Hall-effect (3‑wire, needs 5V reference) or variable reluctance (VR, 2‑wire AC) depending on model — consult factory manual
Hall-effect (typical): square wave 0–5 V, frequency proportional to shaft speed. Reference and ground should be stable 5 V and chassis ground.
VR sensor (typical): AC sine wave whose amplitude and frequency increase with speed — amplitude can range from a few hundred millivolts at low speed to volts at higher speed
Expected behavior: smooth, continuous waveform with frequency proportional to turbine/input shaft rpm; no intermittent dropouts or noise spikes
Always confirm exact resistance, voltage and waveform specifications from Nissan service data for the specific vehicle/year

Connect a professional scan tool, note P1900 and any related codes, and record freeze frame/live data for turbine speed, input speed, output/vehicle speed and engine rpm.
Visually inspect the turbine speed sensor, connector and wiring for damage, corrosion, fluid ingress or loose mounting. Repair or protect any exposed wiring.
Backprobe the sensor connector. With ignition on and engine cranking, observe the signal on the scan tool and with a scope (preferred) or DVOM. Look for intermittent signal loss or excessive noise.
Perform a wiggle test on the wiring harness and connector while monitoring the live signal to reproduce intermittent behavior.
Measure sensor resistance (if specified) and check reference voltage and ground integrity. Repair any open, shorted or high-resistance circuits.
If the sensor is VR type, check AC output with oscilloscope while rotating the input shaft or running the vehicle; if Hall type, check square wave output and 5 V reference.
Repair or replace damaged wiring, connectors or the sensor as required. Clean and apply dielectric grease to connectors after repair.
Clear codes and road test to confirm repair. If intermittent code returns after harness and sensor are confirmed good, consider TCM input circuit testing or TCM as a last resort and consult Nissan technical service information.

Wiring chafe at a harness flex point near the transmission tunnel or shift linkage
Corroded connector at the sensor where moisture or transmission fluid has entered
Sensor degraded by heat or contamination causing intermittent output
Loose or high resistance ground or reference feed at TCM or chassis ground
Aftermarket wiring or recent repairs disturbed the circuit

⚠️ Status

Intermittent turbine speed sensor circuit detected by TCM; MIL may be on and transmission shift behavior can be affected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours

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P1900 — Turbine Speed Sensor Circuit Intermittent