P0700 - Transmission Control System Malfunction
TCM requested MIL illumination (transmission fault present).
Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.
Code Overview
TCM requested MIL illumination (transmission fault present).
Common Causes
- Transmission fault stored in the TCM
- Transmission wiring, power, or ground issue
- Shift solenoid or transmission sensor failure
- Fluid, pressure, or internal transmission problem
Symptoms
- Check-engine light with one or more transmission companion codes
- Harsh shifting, delayed engagement, or limp mode
- Transmission warning behavior even when the engine runs normally
Diagnostic Steps
- Scan the transmission control module for the companion fault codes first
- Check transmission fluid level and condition if the unit has a serviceable dipstick
- Inspect transmission connectors, power feeds, and grounds
- Diagnose the companion TCM codes before replacing major parts
Repair Difficulty
Advanced
General difficulty estimate for the most common repair path.
Likely Repairs & Cost Guides
Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.
Estimator-ready next step after the fault path is confirmed.
Estimator-ready next step after the fault path is confirmed.
Estimator-ready next step after the fault path is confirmed.
Estimator-ready next step after the fault path is confirmed.
Related OBD Codes
Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.
Next Steps
Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.