Gear Shift Position Circuit Low
Diagnostic trouble code P0916 indicates that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected a low voltage condition in the gear shift position sensor circuit. This means the signal voltage from the sensor has fallen below the manufacturer's specified threshold, preventing the module from accurately determining the current gear selection.
This code is considered high severity because the inability of the transmission module to determine the gear position can lead to erratic shifting, transmission limp mode, or the vehicle failing to start due to the neutral safety switch function.
Common symptoms
- Illuminated Check Engine Light
- Harsh or erratic transmission shifting
- Transmission stuck in limp mode (default gear)
- Vehicle will not crank or start
- Incorrect gear indicator displayed on the dashboard
Likely causes
- Faulty gear shift position sensor
- Damaged, corroded, or loose wiring and connectors in the sensor circuit
- Misadjusted gear shift linkage or cable
- Short to ground in the gear shift position sensor circuit
- Internal transmission mechanical failure affecting the shift shaft
- Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM)
What to check before replacing parts
Visually inspect the wiring harness and connectors associated with the gear shift position sensor.
Look for: Look for frayed wires, melted insulation, pushed-out pins, or corrosion that could cause a short to ground or high resistance.
Check the adjustment of the gear shift linkage or cable.
Look for: Ensure the linkage moves smoothly and aligns properly with the detents on the transmission, as misalignment can cause incorrect sensor readings.
Test the reference voltage and ground at the gear shift position sensor connector.
Look for: Using a multimeter, verify that the sensor is receiving the correct reference voltage (usually 5V) and has a solid ground. A missing voltage or poor ground indicates a wiring or module issue.
Measure the signal voltage output from the gear shift position sensor while moving the shifter through all gears.
Look for: The voltage should change smoothly and match the manufacturer's specifications for each gear position. If the voltage remains low or drops out, the sensor is likely faulty.
Perform a continuity and short-to-ground test on the signal wire between the sensor and the PCM/TCM.
Look for: Disconnect both ends of the harness and check for continuity. Also, check for continuity to ground; if present, there is a short to ground in the wiring harness.
This page explains the generic P0916 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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