P0701
Transmission Control System Range/Performance.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 01
- FaultThe specific fault in that area
What it means
P0701 is the generic code for a Transmission Control System Range/Performance fault. The transmission control module (TCM) has detected that something in the transmission control system is operating outside its expected range or not performing as commanded. The code is deliberately broad, so it does not point to one component and other transmission codes are usually stored alongside it.
Symptoms
- Transmission warning light or malfunction indicator lamp on
- Harsh, delayed or erratic gear changes
- Transmission stuck in one gear or in limp-home mode
- Slipping or flaring between gears
- Poor acceleration or reduced economy
- Torque converter shudder or unexpected engine revs
Possible causes
- Low, degraded or contaminated transmission fluid, or incorrect fluid typelikely
- Faulty or sticking shift solenoid or pressure control solenoidlikely
- Wiring or connector faults in the transmission harness, such as chafing, corrosion or water ingresspossible
- Faulty transmission speed, temperature or pressure sensor giving implausible readingspossible
- Valve body wear, blocked passages or internal hydraulic problemspossible
- Faulty TCM, or outdated TCM software where the manufacturer has issued a known update (model dependent)rare
- Internal mechanical wear such as worn clutches or a failing torque converterrare
How to diagnose
- Read all stored and pending codes and record the freeze frame data, noting any other transmission, engine or communication codes, as these will guide the diagnosis.
- Check the transmission fluid level, condition and smell, using the correct procedure and temperature for the model, as some sealed units need specific checks.
- Inspect the transmission wiring harness and connectors for damage, corrosion, leaks or fluid contamination.
- Check the battery condition and charging voltage, as low voltage can upset control units and solenoids.
- View live data for input and output shaft speeds, gear selected, gear ratio, fluid temperature and line pressure, and compare commanded with actual values.
- Test solenoid and sensor circuits for resistance, supply and signal against the manufacturer's specification for that transmission.
- Check for relevant technical service bulletins or software updates for the specific vehicle and transmission.
- If electrical and fluid checks are fine, carry out pressure tests or a transmission inspection to assess internal hydraulic and mechanical condition.
How to fix
- Correct the fluid level or replace degraded fluid and filter with the specified type, if the manufacturer permits servicing.
- Replace faulty solenoids, sensors or the affected valve body components.
- Repair or replace damaged wiring, connectors or terminals in the transmission circuits.
- Update or reflash the TCM software only where an updated calibration is a known fix for the vehicle.
- Repair or replace the TCM if testing confirms it has failed.
- Overhaul or replace the transmission if internal wear is confirmed.
Can I keep driving?
Medium severity
The car may be driveable for short distances, but poor shifting or limp mode can cause further damage and unsafe behaviour. Have it diagnosed soon and avoid heavy loads or long journeys until it is checked.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.