GarageDex

P0700: Transmission Control System (MIL Request)

GarageDex's OBD-II reference explains that code P0700 means "Transmission Control System (MIL Request)" - The transmission control module has found a fault and is asking the engine computer to turn on the check-engine light. P0700 itself is just the flag - a companion transmission code (P07xx) has the real detail.

Severity

Moderate - drivable, but don't put it off

If shifting is affected or it's in limp mode, drive gently to diagnosis; a scan for the paired code is the real next step.

Symptoms

Common causes (most to least likely)

  1. Whatever the companion P07xx code points to (solenoid, speed sensor, low/old fluid, etc.)
  2. Low or degraded transmission fluid
  3. Failing shift solenoid

How to fix P0700

  1. Scan for the companion transmission code and diagnose THAT
  2. Check transmission fluid level and condition first
  3. Address the specific sub-code

Guidance only - confirm the cause with a scan before replacing parts. Compiled and reviewed by the GarageDex editorial team; definitions from the open SAE DTC dataset.

Tools & parts for P0700

Confirm the cause before you buy anything - a code points to a system, not a guaranteed part. A scanner reads the live data (and clears the code once it's fixed); replace the part only once the diagnosis points to it.

Start here: OBD2 scannerRead live data & clear the codeShop scanners Likely part (if diagnosis confirms)OBD2 scanner transmissionShop part

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Frequently asked

What does the P0700 code mean?

GarageDex's OBD-II reference explains that code P0700 means "Transmission Control System (MIL Request)" - The transmission control module has found a fault and is asking the engine computer to turn on the check-engine light. P0700 itself is just the flag - a companion transmission code (P07xx) has the real detail.

What are the symptoms of P0700?

Common symptoms: Harsh, delayed, or erratic shifting; Transmission in limp mode (stuck in one gear); Check-engine light.

What causes a P0700 code?

The common causes, most to least likely: Whatever the companion P07xx code points to (solenoid, speed sensor, low/old fluid, etc.); Low or degraded transmission fluid; Failing shift solenoid.

Is it safe to drive with a P0700 code?

If shifting is affected or it's in limp mode, drive gently to diagnosis; a scan for the paired code is the real next step.

How do I fix a P0700 code?

Scan for the companion transmission code and diagnose THAT Check transmission fluid level and condition first Address the specific sub-code Confirm the cause with a scan before replacing parts.