P0700 — Transmission control system — malfunction indicator lamp request

P0700 means the transmission control system has requested the malfunction indicator lamp. It flags a diagnostic concern rather than identifying a failed part. A basic OBD reader may show P0700 without the detailed transmission-control-module codes. Read the TCM with a compatible tool. P0700 alone does not justify replacing the transmission or TCM; vehicle-specific cases can involve power supply, communication or software.

Affected system: Powertrain

Symptoms

• Check-engine light; a transmission warning may also appear.
• Abnormal shifting, limited power or unavailable functions may occur, but P0700 alone does not guarantee these symptoms.

Possible causes

• A condition monitored by the TCM, identified through its detailed fault codes.
• A power-supply or communication problem, where associated codes and measurements support that path.
• A vehicle-specific software condition; a bulletin for one model does not automatically apply to other transmissions.

What to check

• Save the complete scan report and associated data before clearing codes.
• Confirm that the tool can access the TCM; record current and stored codes.
• Diagnose the detailed TCM codes. If communication is unavailable, follow the vehicle wiring diagram to check module power and the network.
• Match bulletins by VIN, model, transmission and software; do not apply an update indiscriminately.
• Stop safely and seek assistance if severe slipping, loss of drive or an overheating warning occurs.
• After correcting the identified cause, recheck the TCM and lamp request; clearing P0700 alone does not verify a repair.

Also written as: P0700-00, P070000, PO700 (some scan tools add the fault-type byte, e.g. -00).