P0700Powertrain
Powertrain · SAE
Transmission Control System — MIL Request
Meaning
A generic code signalling that a fault is present in the transmission control module (TCM). The TCM asks the engine ECU to turn on the warning light; the actual fault is in one or more codes stored in the transmission.
Common causes
- One or more faults stored in the transmission module (TCM)
- Faulty transmission sensors (input/output speed)
- Solenoids or hydraulic pressure out of spec
- Degraded transmission fluid or wrong level
- Faulty transmission wiring/connector
Symptoms
- Check engine light on
- Harsh, delayed or missing shifts
- Transmission limp mode (fixed gear)
- Possible slipping or jerking
Severity
Moderate/serious: P0700 is only the indicator; the TCM codes must be read to understand the real transmission fault.
What to do
- Read the transmission module (TCM) codes, not just the engine ones
- Check transmission fluid level and condition
- Check transmission sensors, solenoids and wiring
- Diagnose the specific TCM code that was found