What it means
The two range sensor channels A and B do not agree on the same gear selector position. Plausibility check fails after debounce.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Range sensor channels A and B independently report selector position so the transmission control unit can check that both signals agree. P2805 sets when the channels identify conflicting positions beyond the system’s plausibility check.
Common causes
Most likely first.
- One sensor mechanically misaligned
- Aged switch contacts on one channel
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Read freeze-frame data and compare the live A- and B-channel readings with the actual selector position.
- Move the selector through each range while watching both channels to identify which one disagrees or changes late.
- Inspect both sensor channels’ connectors, linkage, and wiring for looseness, corrosion, damage, or signs of misalignment.
- Check A- and B-channel supplies, grounds, and signal circuits for opens, shorts, or poor connections using the wiring diagram.
- Test both channel outputs and sensor alignment through the full selector travel against the manufacturer’s specification.
Common fixes
- Secure or clean the connector for the channel with poor contact.
- Adjust the misaligned range sensor or selector linkage if testing confirms the position is off.
- Repair damaged wiring or terminals on the A or B channel identified by testing.
- Replace the range sensor or switch if one channel’s contacts remain inconsistent after alignment and circuit checks.
Can I keep driving?
Avoid driving if the range display is wrong, shifts are erratic, or limp mode occurs because the controller is receiving conflicting selector information. Stop if the vehicle does not respond to the selected range.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.