P0880 The transmission computer's power supply circuit looks wrong to the engine computer

TCM power input signal malfunction

P0880 in short

P0880 means the engine computer has seen a fault in the power feed to the transmission control module. A blown fuse or fusible link, a bad power relay, or an open or shorted wire is the usual cause. The car often still runs, but shifting can turn erratic, so get it checked soon.

The transmission control module (TCM) needs a steady power feed to run the transmission. That feed normally passes through a fuse, fusible link or relay. P0880 is set when the engine computer sees the voltage on that circuit is not what it should be.

Kelley Blue Book and TroubleCodes.net both list a bad relay, a blown or corroded fuse, an open or shorted wire, and a TCM or engine computer fault or programming error. Kelley Blue Book adds battery and connector problems and says diagnosis is difficult because the code is generic.

Symptoms in both references include harsh or erratic shifting and a check engine light. TroubleCodes.net also lists stalling at idle and speedometer problems, and says the transmission may go into limp mode on some vehicles.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Blown fuse, burnt fusible link or bad power relay

    Common general cause
    Why it ranks here
    Both references list the fuse, fusible link and relay first, and TroubleCodes.net says to check these before anything else.
    What would change this
    Rises if a fuse or link is open or a swapped relay clears the fault. Falls if all test good.
    How to test the underhood fuse block (engine compartment fuse box)

  2. Open, shorted or corroded power wiring or connector

    Common general cause
    Why it ranks here
    Both references list open or shorted circuits; Kelley Blue Book also lists connector pin and battery power faults.
    What would change this
    Rises if voltage at the TCM with ignition on is low or absent while the fuse is good. Falls if full battery voltage reaches the TCM.

  3. TCM or engine computer fault or programming error

    Possible — needs testing
    Why it ranks here
    Both references list the module itself, but after the power circuit; no make-specific evidence was found for this code.
    What would change this
    Rises if the power and ground reach the TCM correctly and the code returns. Falls if a circuit fault is found.
    How to test the transmission control module (tcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes from the engine and transmission computers; other transmission codes often appear with P0880.

    Low riskTool: OBD-II scan tool

    • IfOnly P0880 is stored

      It meansCheck the fuses and relay.

      Go to step 2

    • IfOther transmission or network codes are stored

      It meansDiagnose those with P0880; a power loss can set several.

      Go to step 2

  2. Check the fuses and fusible links for the transmission computer using the fuse chart in the owner's manual, and try an identical relay in its place.

    Use cautionTool: multimeter or test light, spare relay

    Warning:Replace a blown fuse only with the same rating, and turn the ignition off first; a fuse that blows again means a short that needs a shop.

  3. Have a shop probe the TCM power circuit with the ignition on, to see whether battery voltage is present, reduced or absent, and inspect the connector.

    Best left to a shopTool: digital multimeter, scan tool

    Warning:Probing a live control module connector can short pins and damage the module; leave this to a shop.

Symptoms

  • Check engine light
  • Harsh, erratic or delayed shifting Gets more serious: stop and have it checked.
  • Engine stalling at idle Gets more serious: stop and have it checked.
  • Speedometer or odometer not working

How to fix

  1. Check the fuses and fusible links for the transmission computer and replace any blown one with the same rating.

On your vehicle

We don't have reviewed vehicle-specific evidence for P0880 yet. The causes and tests above apply across vehicles.

  • P0884Transmission control module power input signal intermittent

    Same system Possible — needs testing

    P0884 is the intermittent version of the TCM power input signal fault.

  • P0700Transmission module requests the check engine light

    Same system Possible — needs testing

    P0700 is the general code that says the TCM has stored its own codes.

All Transmission codes

P0880 questions

Is it safe to drive with P0880?

Often the car still runs, but shifting may become erratic and some vehicles go into limp mode. Kelley Blue Book says to consult an expert before continuing to drive.

Sources and review

  1. P0880 - TCM Power Input Signal — Kelley Blue Book
  2. P0880 - Transmission Control Module Power Input Signal Malfunction — TroubleCodes.net
Last reviewed
Written by
Saurabh K.
Editorial review
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Technician review
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