Pxxxx · Powertrain
P0700
Transmission Control System Malfunction
CriticalPowertrain ECU
What it means
The Transmission Control Module (TCM) has reported a fault to the ECM. P0700 itself is generic — always pull the secondary TCM-specific codes (P07xx) for the actual problem.
Common causes
Listed in rough order of frequency. Verify with vehicle-specific service info before parts replacement.
- 01Low transmission fluid level
- 02Failed or contaminated transmission fluid
- 03Internal transmission solenoid failure
- 04TCM communication fault (often U-code companion)
- 05Wiring harness damage between TCM and transmission
Affected systems
ECUs and subsystems that report or are affected by this code.
Transmission Control Module (TCM)CAN bus
Get vehicle-specific diagnosis for P0700
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Ask the forums about P0700Critical-severity code
This code typically prevents the vehicle from starting, running normally, or operating safely. Diagnose carefully before clearing — clearing without fixing the root cause often masks deeper problems.