Powertrain, generic · Transmission

P0700 Transmission Control System (MIL Request)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0700 is a notice code: the separate transmission control module has stored an emission-related fault of its own and asks the engine module to switch on the check engine light. The actual fault – a sensor, solenoid, ratio or speed sensor code – is stored in the transmission module and must be read with a tool that can address it; simple OBD readers often show only P0700. GM's engine module reads the request message from 3 s after start; Subaru-based systems (Saab 9-2X) light the MIL at once and clear it after three fault-free cycles. Ford's engine modules with integrated transmission control do not use P0700. Any limp mode comes from the transmission fault, not from P0700.

Likely causes

Actual fault stored in the transmission module (sensor, solenoid, ratio, speed sensor)
Wrong transmission fluid level or condition causing slip or ratio codes
Harness or connector at the transmission corroded or damaged
Low system voltage or weak battery
Transmission module or software faulty

Symptoms

  • Check engine light, possibly transmission warning
  • Depending on the transmission fault: limp mode, harsh or delayed shifts
  • Often no symptoms if the fault was intermittent
  • Simple OBD reader shows only P0700

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,500
Time0.5–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Read codes from the transmission module itself
  2. Check transmission fluid level and condition

Parts involved

transmission control moduleengine control modulecan bus

Related codes

P0701P0702P0613P0614P0705P0710

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.