Weak or poorly charged battery, or poor battery terminal connections; Corroded, loose or damaged TCM power or earth connections and connectors; Blown or faulty fuse, or a poor connection in the fuse or relay box feeding the TCM; Charging system fault (alternator output low) causing system voltage to dip; Damaged wiring between the fuse box and the TCM, such as chafing, high resistance or a partial open circuit; Faulty ignition switch or power supply relay feeding the TCM (depends on model); Internal TCM fault, including water ingress in a gearbox-mounted unit.

P0882

TCM Power Input Signal Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
8: AreaTransmission
82: FaultThe specific fault in that area

What it means

P0882 means the transmission control module (TCM) has detected that its power supply input voltage is lower than the expected range. The TCM monitors its ignition or battery feed voltage, and if it drops below the calibrated threshold for long enough, the code is set. Low voltage can cause the TCM to behave unpredictably, so gearbox operation may be affected.

Symptoms

Gearbox warning light or malfunction indicator lamp on
Transmission stuck in one gear (limp mode)
Harsh, delayed or erratic gear changes
No shifting or loss of drive in some gears
Intermittent fault that comes and goes with engine load or bumps
Other warning lights or communication fault codes present at the same time

Possible causes

Weak or poorly charged battery, or poor battery terminal connectionslikely
Corroded, loose or damaged TCM power or earth connections and connectorslikely
Blown or faulty fuse, or a poor connection in the fuse or relay box feeding the TCMlikely
Charging system fault (alternator output low) causing system voltage to dippossible
Damaged wiring between the fuse box and the TCM, such as chafing, high resistance or a partial open circuitpossible
Faulty ignition switch or power supply relay feeding the TCM (depends on model)possible
Internal TCM fault, including water ingress in a gearbox-mounted unitrare

How to diagnose

Read all stored codes and freeze frame data, noting whether other low voltage or communication codes are present and under what conditions the fault set
Check battery condition and state of charge, and inspect terminals for tightness and corrosion
Measure system voltage with the engine off and running to confirm the charging system is working within specification
Inspect the TCM fuses and relays per the wiring diagram for the vehicle, checking for poor contact as well as blown fuses
Visually inspect TCM connectors and wiring for corrosion, water ingress, chafing or pushed-out pins
Voltage-drop test the TCM power and earth circuits under load, wiggling the harness to look for intermittent faults
Check for manufacturer service information on the TCM supply circuit, as location and layout depend on the model and gearbox type
Only after supply and earth are proven good, consider testing or replacing the TCM as per manufacturer procedure

How to fix

Recharge or replace the battery and clean and tighten the terminals
Repair or replace corroded or damaged connectors, terminals and earth points
Replace faulty fuses, relays or the ignition switch, and find the reason a fuse blew
Repair or replace damaged wiring between the supply and the TCM
Repair the charging system if alternator output is low
Replace or repair the TCM, and carry out any required programming, only once the cause is confirmed as internal

Can I keep driving?

Medium severity

The car may be driveable if it shifts normally, but the gearbox could drop into limp mode or lose drive without warning. Get it checked soon, and avoid long journeys or overtaking situations until it is fixed.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.