Code
P1922
Generic
P — Powertrain
Transmission Input Shaft Speed Sensor Circuit Fault
Views:
UK: 11
EN: 12
RU: 11
AI status
Completed
Completed
100%
Causes
- Open, shorted, or corroded wiring or connector between ISS sensor and TCM
- Failed or contaminated input shaft speed sensor (magnetic/VR or Hall)
- Damaged or missing reluctor/gear ring on input shaft
- Poor sensor air gap or incorrect installation
- Faulty TCM or poor ground/reference to the sensor circuit
- Intermittent mechanical damage inside the transmission
Symptoms
- Check Engine / Transmission malfunction lamp illuminated
- Harsh, delayed, or erratic shifting; transmission may go to limp mode
- Inability to shift into certain gears
- Inconsistent or no ISS speed reading in live data
- Unexpected torque interruptions or stalling during shifts
What to check
- Scan for P1922 and any related DTCs (e.g., transmission or speed sensor codes)
- Compare live ISS reading with engine RPM and vehicle speed while driving or on a lift
- Visually inspect ISS connector and wiring for damage, corrosion, or loose pins
- Backprobe sensor connector for reference voltage/ground (if active sensor) or measure AC output (if VR type)
- Inspect input-shaft reluctor/gear and sensor air gap for damage or debris
Signal parameters
- Sensor types: Hall-effect (digital) or VR/magnetic (AC).
- Hall sensor: square wave 0–5 V (some systems 0–12 V) referenced to vehicle ground; frequency proportional to shaft RPM.
- VR sensor: AC sine/triangle waveform; amplitude increases with RPM (low rpm = small millivolt signal; higher rpm = higher VAC).
- Expected behavior: clean, consistent pulses with frequency increasing smoothly with shaft speed; no excessive noise or dropouts.
- If unsure of type, check OEM service data for exact voltage/resistance/frequency specs.
Diagnostic algorithm
- Retrieve freeze frame and note conditions when the code set; record related codes.
- Inspect wiring harness and connector at the ISS for corrosion, bent pins, damaged insulation, or water intrusion; repair/clean as needed.
- With connector disconnected, check sensor resistance (if specified by OEM) and compare to spec; for VR sensors expect a finite coil resistance, Hall sensors often show open/OL.
- Reconnect and backprobe harness while cranking/rotating input shaft: for Hall sensors verify reference voltage and pulsed output; for VR sensors measure AC voltage while rotating. Use an oscilloscope for best waveform verification.
- Wiggle test wiring while monitoring live data to find intermittent faults.
- Inspect the reluctor/trigger ring on the input shaft for missing/broken teeth, debris, or excessive wear; correct mechanical issues.
- Check TCM power, ground, and communication lines; measure for shorts to battery or ground on the sensor circuit.
- If wiring and sensor test good but signal is still incorrect, replace the ISS sensor and re-test.
- After repairs clear codes and perform a road test or dyno run while monitoring ISS vs vehicle speed and engine RPM to confirm repair.
- If problem persists with verified sensor and wiring, consider TCM fault — consult OEM procedures before replacing control module.
Likely causes
- Connector corrosion or bent pins at ISS harness
- Chafed wiring rubbed through to ground or power
- Sensor damaged by debris or fluid contamination
- Reluctor tooth missing or coated with metal shavings
- Failed Hall sensor electronics or VR coil short/open
Fault status
Status
Transmission Input Shaft Speed Sensor Circuit Fault — signal missing/intermittent/out of range; check sensor, wiring, reluctor, and TCM inputs.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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