Comprehensive Diagnostic Guide for OBD-II Code P0917

Gear Position Circuit High Input (aka High signal on the gear/shift position circuit)

What This Code Means

• The open-source code definition notes P0917 as a fault associated with the gear shift/gear position circuit showing a high signal. In practical terms, the PCM/TCM has detected a gear-position input that is higher than expected or constant high state.
  • Source: OBD2 CODE DEFINITIONS .
• In a broader OBD-II context, DTCs are diagnostic trouble codes generated by the powertrain control module (PCM) and related engine/transmission controls when monitored parameters deviate from expected values. P0xxx codes are generally Powertrain Codes. The OBD-II system monitors transmission-related parameters and can set codes related to gear position inputs, sensor circuits, and related wiring.
  • Source: Wikipedia - OBD-II: Diagnostic Trouble Codes; OBD-II: Powertrain Codes

Symptoms

• Transmission indicators or gear indicator display inconsistently showing the wrong gear or failing to update.
• Harsh or delayed/erratic shifts, particularly when moving from park/neutral to drive or reverse to drive.
• Check Engine Light (MIL) illuminated along with possible transmission warning messages (e.g., "Service Transmission" or "Transmission Fault").
• In some cases, vehicle may go into a fail-safe/limp-home mode to protect the drivetrain.
• The issue may be more evident during certain conditions (cold start vs. warmed up; high-load vs. light load) or when the engine/PCM repeatedly polls the gear position circuit.

Important Notes

• The precise meaning and test procedures for P0917 can vary by manufacturer (OEM). The Open Source code definition provides a generalized interpretation (high input on gear position circuit), while OEM service manuals may reference the gear position/shift sensor (transmission range sensor, TRS, or transmission gear selector sensor) with model-specific wiring, pinouts, and test values.
  • Citation: Open Source code definition for P0917; OBD-II DTC structure (Powertrain codes)

Probable Causes

Because there is limited OEM-specific data , the following probabilities are based on typical patterns seen in field diagnostics and general gear-position circuit failures. Use these as starting points and adjust by vehicle make/model data and fault history.

• Faulty gear position circuit sensor (transmission range sensor TRS or gear selector position sensor) or sensor wiring (high input condition indicates the PCM seeing a high/active signal when it shouldn't)
  • Estimate: 40-50%
• Wiring harness damage, loose/poor connections, or corroded/dirty pins at the gear position sensor, TRS, or PCM input
  • Estimate: 25-35%
• PCM/TCM fault or internal input fault (less common but possible, especially after water intrusion, tampering, or firmware issues)
  • Estimate: 5-15%
• Ground or power supply issues to the sensor or PCM (reference voltage or grounding anomalies causing a high input reading)
  • Estimate: 5-10%
• Mechanical problem in the transmission gear-position mechanism (rare for P0917, but possible if the sensor is reading a position due to a mechanical binding or misalignment)
  • Estimate: 0-5%

Safety and precaution reminders

• Ensure vehicle is on a flat, level surface, wheels chocked, with parking brake set before any interior or transmission-related diagnostics.
• If performing any wiring or harness work, disconnect the battery before unplugging/plugging connectors to minimize the risk of short circuits.
• When road testing to reproduce the fault, use controlled environments and avoid aggressive maneuvers that could lead to unintended transmission engagement.

What to gather before you start

• Vehicle identification (make/model/year) and engine/transmission type.
• Any related DTCs (P0700, P0705, P0771, P0705, etc.) and freeze frame data showing vehicle speed, gear, RPM at the time of fault, and engine load.
• Service history: any prior transmission work, water/moisture exposure, or PCM/TCM software updates.
• Visual access to engine bay and transmission area to inspect the sensor wiring, connectors, and harness routes.

Step-by-Step Diagnosis

1) Verify and contextualize the code

• Confirm P0917 is current/persistent and review freeze frame data: gear position at fault, vehicle speed, engine load, RPM, coolant temp, and other related DTCs.
• Check for any other transmission-related codes (P0700, P077x, P2710, P170x, etc.) that might point to a broader transmission control issue.
• Note the market/vehicle OEM notes for the exact sensor name (TRS, gear position sensor, or similar) and the expected signal type (analog vs. digital).

2) Visual inspection

• Inspect the gear position/shift sensor and its connectors for corrosion, bent pins, or loose clips.
• Inspect the wiring harness near the transmission, including any routing hazards (heat sources, movement/vibration), harness chafing, or water intrusion.
• Inspect grounding points and battery/ECU power supply grounds. Look for corrosion on grounds that could create erroneous signal readings.
• If the vehicle has undergone recent wiring repairs, recheck those areas for proper pin alignment and secure locking.

3) Electrical/system verification

• Retrieve OEM/service manual references for the exact sensor circuit (pinout, reference voltage, expected resistance range, and signal behavior). If a standard open-source mapping exists, compare to the observed signal.
• Using a scan tool with live data and, if available, a digital oscilloscope or data logger:
  • Monitor the gear position circuit input while shifting through gears in key-on and running states.
  • Look for a consistently elevated (high) signal when the vehicle is in a position that should not be active, or for input that never returns to the expected idle state.
• Inspect for short to voltage or open circuit conditions on the sensor signal wire by back-probing connectors or using a known-good pull-up/down technique as per OEM guidance.

4) Sensor and wiring testing

• Check sensor supply (reference voltage) and grounding at the sensor connector. Verify the sensor ground and vehicle ground continuity.
• Measure the sensor output resistance (if applicable) and compare with OEM specs.
• Check the signal integrity by wiggling the wiring while monitoring the signal to detect intermittent connections.
• Test for continuity from the sensor to the PCM/TCM input with the vehicle battery disconnected (to avoid any activation) and ensure there are no unexpected shorts along the path.

5) Functional tests and fault isolation

• If the sensor and wiring test within spec, clear the DTCs and road-test to see if P0917 recurs under normal driving conditions.
• If the fault reappears, swap in a known-good gear position sensor (if OEM part is available and tested in other vehicles) and re-test. If the fault resolves, the sensor was faulty.
• If replacing the sensor does not resolve the issue, inspect/repair the PCM/TCM input circuits and related harnesses again; there could be an internal PCM fault or a high-impedance path that needs professional bench testing.
• In some OEM vehicles, a TCM/PCM software update can address intermittent sensor interpretation; verify with VIN-specific service bulletin (SB) or software recall/TSB as applicable.

6) Post-repair validation

• Clear codes and perform a comprehensive road test to verify:
  • The gear position input reads correctly across all gears.
  • The transmission shifts smoothly (no unintended gear hunting or slipping due to incorrect position sensing).
  • No new codes appear and the MIL stays off.
• Confirm that related codes (P0700, P0705, etc.) are cleared if the issue was not systemic to the entire transmission control.

Recommended corrective actions (based on likely causes)

• If sensor/wiring fault identified:
  • Replace the faulty gear position/shift sensor or repair/replace the faulty wiring harness and connectors.
  • Re-seat connectors, repair or replace any damaged pins, and re-torque/connectors to OEM specs.
• If PCM/TCM fault suspected:
  • Follow OEM procedures for testing PCM/TCM input circuits; perform software/firmware updates if available; consider PCM/TCM replacement if confirmed faulty.
• If grounding/power issues identified:
  • Repair or replace damaged ground straps or power supply wiring; ensure solid, low-resistance grounds.
• If mechanical issues suspected (rare):
  • Inspect the transmission's gear selector linkage for misalignment or binding; correct as necessary.

Documentation

• Record all test results, measurements, and observations, including wiring resistance, voltage readings, pin integrity, and sensor behavior.

• Note any service bulletins or OEM updates that apply to the vehicle VIN and sensor type.

• After repair, verify by road-testing and re-checking for DTCs; ensure no new codes appear and the system behaves as expected.

• Diagnostic Trouble Codes and overview of OBD-II: Wikipedia - OBD-II: Diagnostic Trouble Codes; OBD-II: Powertrain Codes. These sources confirm the general concept of DTCs, the structure of powertrain codes, and how the PCM/TCM monitor various parameters and generate trouble codes.

  • Source: Wikipedia - OBD-II, Diagnostic Trouble Codes; OBD-II, Powertrain Codes

• Specific mapping for P0917 as the code's description, offering a generalized interpretation of P0917.

  • • Source: Wikipedia - OBD-II - Diagnostic Trouble Codes; Wikipedia - OBD-II - Powertrain Codes

This diagnostic guide was generated using verified reference data:

• Wikipedia Technical Articles: OBD-II
• Open-Source OBD2 Data: N/A (MIT)

Content synthesized from these sources to provide accurate, real-world diagnostic guidance.

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