Transmission

P0882 — Transmission Control Module (TCM) Power Input Signal Low

Severity: medium Drive with care, to a shop

What P0882 means

The transmission control module (TCM) constantly monitors its own supply voltage. P0882 sets when that voltage falls below the allowed threshold. At low voltage the module may control solenoids poorly and drop off the communication network.

Symptoms

  • Transmission limp mode, stuck in one gear
  • Intermittent or missing shifts
  • Several U-series communication codes at once
  • Check Engine or transmission warning light on
  • Harsh or erratic shifting
  • Problem comes and goes, often over bumps or with heavy electrical load

Possible causes

  1. Weak or failing battery
  2. Corroded or loose battery terminals and TCM power connections
  3. Blown TCM power fuse
  4. Failing alternator causing low system voltage
  5. Open, chafed or poorly connected wiring
  6. Power circuit shorted to ground
  7. Faulty TCM

How to diagnose

  1. Scan all modules and note freeze frame data and any U-codes
  2. Test battery voltage at rest (about 12.4-12.7 V) and running (about 13.5-14.7 V)
  3. Inspect and tighten battery terminals and main body and engine grounds
  4. Check the TCM power fuses and relays
  5. Using the wiring diagram, test voltage and voltage drop at the TCM connector under load
  6. Check the TCM ground and inspect the harness and connector for chafing, moisture and corrosion
  7. Test the alternator output and ripple
  8. If power is good, evaluate the TCM and reprogram or replace it as needed

Common fixes

  • Charge or replace the battery
  • Clean and tighten terminals, restore grounds
  • Replace the fuse after finding why it blew
  • Repair the harness or TCM power connector
  • Repair or replace the alternator
  • Reprogram or replace the TCM

Questions and answers

Can I drive with P0882?

Only briefly and carefully, to a shop. The transmission may go into limp mode and the module could lose power at any time.

Can a weak battery cause P0882?

Yes, it is one of the most common causes. Check the battery, terminals and alternator before suspecting the TCM.

Why did U-codes appear with P0882?

Low voltage makes modules drop off the CAN network, which sets communication codes. Fix the power problem, clear the codes and recheck.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.