P0700: Transmission Control System Malfunction
System: TransmissionThe transmission computer found a problem and asked the engine computer to turn on the check engine light.
Severity: 2 of 4
If the car shifts and drives normally, get the transmission codes read soon. If the transmission slips, flares between gears, shifts harshly, or is stuck in one gear (often called limp mode), park it and have it checked. Driving on a slipping transmission can turn a modest repair into a rebuild, and a sudden loss of drive in traffic is dangerous.
Estimate range covers the repairs listed below; see the cost breakdown. A flashing check engine light, a hot temperature gauge, or brakes that feel different mean stop driving and get help.
What P0700 means
On most vehicles with an automatic transmission, a separate transmission control module watches the transmission. When it stores a fault, it tells the engine computer, which sets P0700 and lights the check engine light.
P0700 is a messenger code. It does not say what is wrong, only that the transmission module has its own code stored. A basic code reader often cannot see that code, so you may need a scanner that reads the transmission module.
Common underlying problems include low or worn fluid, shift solenoids, speed sensors, the range sensor, wiring, and internal wear.
Common causes (cheapest likely first)
- Low, burnt, or wrong transmission fluid. Check the level the way your owner manual describes; some transmissions have no dipstick.
- Shift solenoid fault. A common electrical code behind P0700.
- Speed sensor or range sensor fault. Bad signals cause odd shifting.
- Wiring or connector problem. Connectors at the transmission can corrode or loosen.
- Internal wear or transmission module fault. Needs proper diagnosis before any big spend.
Symptoms
- Check engine light
- Harsh, late, or early shifts
- Slipping or flaring RPM
- Stuck in one gear (limp mode)
- Transmission warning light on some vehicles
DIY difficulty: Moderate to hard
Reading the transmission codes and checking fluid are good first steps. Solenoids are external on some transmissions and internal on others. Many shops and parts stores can read transmission codes with a better scanner.
Tools: Scanner that reads transmission module codes, Correct transmission fluid, Funnel, Service manual for fluid check procedure
Estimated repair cost
This is an estimate, built from typical parts price ranges plus labor hours times an assumed shop rate of $110 to $190 per hour. Actual prices vary by vehicle, region, and shop. Diagnosis fees are often extra.
| Repair | Parts | Labor | Estimate (low / high) |
|---|---|---|---|
| Transmission code scan and diagnosis | $0 to $0 | 0.5 to 1.5 h | $0 + 0.5 × $110 = $55 $0 + 1.5 × $190 = $285 |
| Transmission fluid service | $40 to $150 | 0.5 to 1.5 h | $40 + 0.5 × $110 = $95 $150 + 1.5 × $190 = $435 |
| Shift solenoid | $30 to $250 | 1.0 to 3.0 h | $30 + 1.0 × $110 = $140 $250 + 3.0 × $190 = $820 |
| Wiring or connector repair | $5 to $60 | 0.5 to 2.0 h | $5 + 0.5 × $110 = $60 $60 + 2.0 × $190 = $440 |
Watch a repair video
Search YouTube for “P0700 fix” videos. Pick a recent video that matches your engine, and confirm the diagnosis before buying parts.
By make
This code works the same way on every make. See brand notes.
Repair manuals
Step-by-step service manuals with torque specs and wiring diagrams:
Haynes manuals Chilton manuals
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Related codes
Check for recalls
Before paying for a repair, enter your VIN in the NHTSA recall lookup. Emissions parts may also be covered by a federal emissions warranty; check your warranty booklet.
FAQ
Is P0700 a serious code?
It can be. The seriousness depends on the transmission code behind it, so get that code read before driving far.
Why can't my scanner find the transmission code?
Many basic readers only talk to the engine computer. You need a scanner that reads the transmission module, or a shop that has one.
Will changing the fluid fix P0700?
Only if low or worn fluid caused the underlying code. On some high mileage transmissions a fluid change does not fix internal wear.
What does it cost to fix P0700?
Small fixes like fluid or a solenoid are covered in the table below. If internal damage is found, a rebuild or replacement costs far more, so get a written quote.