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P0887 – TCM Power Relay Control Circuit High (OBD2)

P0887 means "TCM Power Relay Control Circuit High". The voltage in the transmission control unit power and communication 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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P0887 quick summary

Fault codeP0887
MeaningTCM Power Relay Control Circuit High
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Carefully and only to a workshop – the gearbox may be in limp mode.
Repair cost€0 – €800

How the transmission control unit is powered and connected

These codes mean the transmission control unit's power supply, power relay or communication with other modules (gear shift module) is faulty.

The transmission control unit needs a stable supply through its power relay and communicates with the engine control unit and gear shift module over the CAN bus or dedicated lines.

Codes P0880–P0892 cover the TCM power input and relay; P0860–P0866 cover communication with the gear shift module and the TCM communication circuit.

Low battery voltage, corroded grounds, a faulty relay or wiring damage typically cause these codes, often together with limp mode.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 17271 (P0887). Both numbers mean the same fault.

Symptoms of P0887

  • Gearbox in limp mode
  • No gear display or warning messages
  • Gear selector not responding
  • Communication codes in other modules
  • Check Engine or gearbox warning

Most common causes of P0887 (most likely first)

Mechanic's Pro Tip

Many gearbox limp-mode complaints with power or communication codes disappear after a new battery and cleaned ground points – check the basics before suspecting the gearbox.

  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 transmission control unit power and communication

  4. 4.Weak battery or charging problem

  5. 5.Corroded ground or supply connection

  6. 6.CAN bus or communication wiring fault

  7. 7.Transmission control unit fault

Step-by-step diagnostic guide

  1. 1

    Check battery and charging

    Measure the battery and charging voltage.

  2. 2

    Check signal and ground

    With the ignition on and the transmission control unit power and communication 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

    Read all modules

    Read codes in all modules for communication and voltage faults.

  4. 4

    Check relay and fuses

    Check the TCM power relay and fuses.

  5. 5

    Measure supply and ground at the TCM

    Measure under load at the TCM connector.

    Multimeter: Supply near battery voltage, ground drop below about 0.1 V.

  6. 6

    Repair and verify

    Repair the supply, ground or communication fault and clear codes.

Frequently asked questions

Can I keep driving with P0887?

Carefully and only to a workshop – the gearbox may be in limp mode.

How much does it cost to fix P0887?

Typical repair costs are 0 € – 800 €, 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 transmission control unit power and communication. Always confirm the cause with the tests above before buying parts.

Can a weak battery cause gearbox codes?

Yes. Low voltage can make the TCM reset or lose communication, causing limp mode.

Where is the TCM?

Depending on the car, in the engine bay, under a seat, in the footwell or on/inside the gearbox.

What is the difference between P0887 and similar codes?

P0887 belongs to a group of codes for the same component that differ in the type or location of the fault: P0884 – TCM Power Input Signal Intermittent; P0885 – TCM Power Relay Control Circuit /Open; P0886 – TCM Power Relay Control Circuit Low; P0888 – TCM Power Relay Sense Circuit; P0889 – TCM Power Relay Sense Circuit Range/Performance; P0890 – TCM Power Relay Sense Circuit Low. 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.