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P0879 – Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent (OBD2)

P0879 means "Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent". The transmission fluid pressure sensor/switch signal briefly drops out or jumps. The fault comes and goes – often with vibration, heat or moisture – so the part may test fine in the workshop.

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P0879 quick summary

Fault codeP0879
MeaningTransmission Fluid Pressure Sensor/Switch D Circuit Intermittent
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Carefully and only to a workshop. Low hydraulic pressure can cause slipping and damage.
Repair cost€50 – €2,500

How gearbox pressure sensors and switches work

Transmission pressure sensors and switches confirm that hydraulic pressure is present in each circuit; these codes cover their signals, low or high fluid pressure and deteriorated fluid.

Many automatic and dual-clutch gearboxes have pressure switches or sensors (A–F) that report whether pressure has reached a clutch circuit. The control unit uses them to confirm shifts and to detect slipping or hydraulic faults.

Codes P0840–P0849, P0870–P0879 and P0987–P0996 report circuit, range, low, high and intermittent faults; P0867–P0869 report fluid pressure that is too low or too high; P0897 means the control unit has calculated that the fluid has deteriorated.

Low pressure can be caused by low fluid level, a clogged filter, a weak pump or internal leaks; sensor faults by internal harness problems.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 17263 (P0879). Both numbers mean the same fault.

Symptoms of P0879

  • Harsh, slipping or delayed shifts
  • Limp mode
  • Gearbox warning light
  • No drive or delayed engagement
  • Fluid service reminder (deteriorated fluid)

Most common causes of P0879 (most likely first)

Mechanic's Pro Tip

For P0897 (fluid deteriorated), a fluid change alone is not enough on many cars – the fluid ageing counter must also be reset with a scan tool, or the code will return.

  1. 1.Loose or corroded connector pin

    Most likely

    Pins that have spread lose contact as the engine vibrates.

  2. 2.Chafed wire that shorts only now and then

    Often where the harness moves with the engine.

  3. 3.Internal intermittent fault in the transmission fluid pressure sensor/switch

  4. 4.Low fluid level or clogged filter

  5. 5.Faulty pressure sensor or switch

  6. 6.Weak oil pump or internal leak

  7. 7.Old, degraded fluid

Step-by-step diagnostic guide

  1. 1

    Read codes and pressure values

    Read the transmission codes and pressure values in live data.

  2. 2

    Do a wiggle test

    With the engine running and the transmission fluid pressure sensor/switch value in live data, gently move the harness and connector. If the value jumps or the code returns, the fault is in that section. Also check pin tension with a matching terminal.

  3. 3

    Check fluid level and condition

    Check fluid using the manufacturer's procedure and temperature.

  4. 4

    Check the sensor circuit

    Measure the sensor supply, ground and signal or switch state.

  5. 5

    Measure line pressure

    Measure real pressure with a gauge where possible.

    Multimeter: Compare with the specification for the gear and engine speed.

  6. 6

    Repair and adapt

    Replace the sensor, filter or fluid, or repair the hydraulic fault, then run adaptations.

Frequently asked questions

Can I keep driving with P0879?

Carefully and only to a workshop. Low hydraulic pressure can cause slipping and damage.

How much does it cost to fix P0879?

Typical repair costs are 50 € – 2500 €, depending on the cause and the vehicle. The most common fixes are: loose or corroded connector pin; chafed wire that shorts only now and then; internal intermittent fault in the transmission fluid pressure sensor/switch. Always confirm the cause with the tests above before buying parts.

What does 'transmission fluid deteriorated' mean?

The control unit has calculated, from temperature and time, that the fluid is worn out and should be changed.

Can a pressure sensor cause limp mode?

Yes. Without a reliable pressure signal, the gearbox may switch to a safe mode.

What is the difference between P0879 and similar codes?

P0879 belongs to a group of codes for the same component that differ in the type or location of the fault: P0876 – Transmission Fluid Pressure Sensor/Switch D Circuit Range/Performance; P0877 – Transmission Fluid Pressure Sensor/Switch D Circuit Low; P0878 – Transmission Fluid Pressure Sensor/Switch D Circuit High; P0897 – Transmission Fluid Deteriorated; P0987 – Transmission Fluid Pressure Sensor/Switch E Circuit; P0988 – Transmission Fluid Pressure Sensor/Switch E Circuit Range/Performance. 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.