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P0999 – Shift Solenoid F Control Circuit High (OBD2)

P0999 means "Shift Solenoid F Control Circuit High". The voltage in the shift solenoid circuit is above the permitted maximum. For most sensors this points to an open signal or ground wire – the signal "floats" up to the reference voltage – or to a short to voltage.

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P0999 quick summary

Fault codeP0999
MeaningShift Solenoid F Control Circuit High
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Carefully and only to a workshop. The gearbox may be stuck in one gear.
Repair cost€80 – €2,000

How shift solenoids work

Shift solenoids direct hydraulic fluid in the valve body to select gears; these codes cover their circuits, performance and timing solenoids.

Each shift solenoid (A, B, C, D, E, F) opens or closes a passage in the valve body. The combination of active solenoids determines which gear is engaged. Shift timing solenoids control how quickly a shift happens.

Codes P0750–P0774 and P0972–P0999 report circuit faults, performance or stuck off, stuck on, electrical and intermittent faults; P0785–P0789 cover the shift timing solenoid.

A failed shift solenoid usually means some gears are missing, the gearbox stays in one gear or shifts harshly. Electrical faults are often in the internal harness or connector; mechanical faults are caused by dirty fluid.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 17383 (P0999). Both numbers mean the same fault.

Symptoms of P0999

  • Gearbox stuck in one gear (limp mode)
  • Missing gears or wrong gear selection
  • Harsh or delayed shifts
  • Check Engine or gearbox warning
  • Engine revs high at speed

Most common causes of P0999 (most likely first)

Mechanic's Pro Tip

If several solenoid codes appear at once, suspect the common feed – the internal harness or the gearbox connector – rather than multiple failed solenoids.

  1. 1.Open circuit in the signal or ground wire

    Most likely

    A loose ground connection is a very common cause.

  2. 2.Signal wire shorted to the 5 V reference or battery voltage

  3. 3.Faulty shift solenoid

  4. 4.Dirty or degraded fluid causing sticking

  5. 5.Internal harness or connector fault

  6. 6.Valve body wear

  7. 7.Transmission control unit fault

Step-by-step diagnostic guide

  1. 1

    Read codes

    Read the transmission codes and note which solenoid is affected.

  2. 2

    Check signal and ground

    With the ignition on and the shift solenoid plugged in, back-probe the signal and ground wires. A signal stuck at reference or battery voltage points to an open ground/signal wire or a short to voltage.

    Multimeter: Ground wire to battery negative: below about 0.1 V. Signal stuck at about 5 V (or 12 V) = open or short to voltage.

  3. 3

    Check fluid

    Check fluid level and condition.

  4. 4

    Measure the solenoid

    Measure the solenoid resistance at the gearbox connector and check for shorts to ground.

    Multimeter: On/off shift solenoids often read about 10–30 Ω; check the specification.

  5. 5

    Command the solenoid

    Use the scan tool to activate the solenoid and listen for the click.

  6. 6

    Repair and adapt

    Replace the solenoid or harness, change fluid and filter, and run adaptations.

Frequently asked questions

Can I keep driving with P0999?

Carefully and only to a workshop. The gearbox may be stuck in one gear.

How much does it cost to fix P0999?

Typical repair costs are 80 € – 2000 €, depending on the cause and the vehicle. The most common fixes are: open circuit in the signal or ground wire; signal wire shorted to the 5 V reference or battery voltage; faulty shift solenoid. Always confirm the cause with the tests above before buying parts.

Can a shift solenoid be replaced without removing the gearbox?

On many gearboxes yes – the solenoids are accessible after removing the oil pan. On some they are part of the mechatronic unit.

Why is my gearbox stuck in third gear?

Many gearboxes use a fixed gear as limp mode when a solenoid or sensor fails, so you can still drive to a workshop.

What is the difference between P0999 and similar codes?

P0999 belongs to a group of codes for the same component that differ in the type or location of the fault: P0986 – Shift Solenoid E Control Circuit High; P0997 – Shift Solenoid F Control Circuit Range/Performance; P0998 – Shift Solenoid F Control Circuit Low; P2706 – Shift Solenoid F; P2707 – Shift Solenoid F Performance or Stuck Off; P2708 – Shift Solenoid F Stuck On. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.