Cause
Faulty shift fork position sensor
The sensor that tells an automated gearbox exactly where each shift fork stands — and therefore whether a gear is truly engaged. When it lies, the gearbox distrusts real gears: the module will not hand torque to a gear it cannot confirm, so a healthy rail's gears go missing from the box's repertoire while nothing mechanical is wrong at all.
Distinguish it from the mechanism with live data: a sensor fault shows a reading that jumps, freezes or sits between positions while the actuator demonstrably moves; a genuinely stuck fork shows a clean reading that refuses to change. The two repairs differ by the entire cost of opening a gearbox, which is why the distinction is worth an hour of measurement.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
5 of the 37 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (37)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2831 Shift Fork A Position Circuit Likely for this code Moderate
- P2832 Shift Fork A Position Circuit Range/Performance Likely for this code Moderate
- P2833 Shift Fork A Position Circuit Low Likely for this code Moderate
- P2834 Shift Fork A Position Circuit High Likely for this code Moderate
- P2835 Shift Fork A Position Circuit Intermittent Likely for this code Moderate
- P2836 Shift Fork B Position Circuit Likely for this code Moderate
- P2837 Shift Fork B Position Circuit Range/Performance Likely for this code Moderate
- P2838 Shift Fork B Position Circuit Low Likely for this code Moderate
- P2839 Shift Fork B Position Circuit High Likely for this code Moderate
- P283A Shift Fork B Position Circuit Intermittent Likely for this code Moderate
- P283B Shift Fork C Position Circuit Likely for this code Moderate
- P283C Shift Fork C Position Circuit Range/Performance Likely for this code Moderate
- P283D Shift Fork C Position Circuit Low Likely for this code Moderate
- P283E Shift Fork C Position Circuit High Likely for this code Moderate
- P283F Shift Fork C Position Circuit Intermittent Likely for this code Moderate
- P2840 Shift Fork D Position Circuit Likely for this code Moderate
- P2841 Shift Fork D Position Circuit Range/Performance Likely for this code Moderate
- P2842 Shift Fork D Position Circuit Low Likely for this code Moderate
- P2843 Shift Fork D Position Circuit High Likely for this code Moderate
- P2844 Shift Fork D Position Circuit Intermittent Likely for this code Moderate
- P2845 Shift Fork A Position Sensor Incorrect Neutral Position Indicated Likely for this code Moderate
- P2846 Shift Fork B Position Sensor Incorrect Neutral Position Indicated Likely for this code Moderate
- P2847 Shift Fork C Position Sensor Incorrect Neutral Position Indicated Likely for this code Moderate
- P2848 Shift Fork D Position Sensor Incorrect Neutral Position Indicated Likely for this code Moderate
- P2851 Shift Fork Position Sensor A/B Correlation Likely for this code Moderate
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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