P0700 medium Severity

P0700: Transmission Control System Malfunction

May cause poor shifting, limp mode, reduced performance or drivability issues depending on specific underlying transmission fault

Overview

Generic transmission control system malfunction code indicating the TCM detected a fault and requested MIL; specific cause requires reading detailed transmission codes from TCM

Common Symptoms

  • Check Engine Light illuminated
  • Poor or erratic transmission shifting
  • Transmission slipping or delayed engagement
  • Vehicle enters limp mode or stuck in one gear
  • Reduced fuel economy

Most Common Causes

Transmission control module (TCM) detected internal fault and set secondary code high

P0700 does not identify specific component but indicates another transmission code logged in TCM memory

Low or contaminated transmission fluid medium

Low or dirty fluid can affect hydraulic control and trigger transmission issues leading to P0700

Faulty transmission wiring or connectors medium

Damaged, corroded, or shorted wiring can interrupt signals to/from TCM and cause fault

Faulty shift solenoids or valve body issues medium

Internal transmission hydraulics issues often accompany P0700 when specific solenoid faults exist

Transmission mechanical wear or failure low

Severe internal damage (clutches/gears) may be underlying cause but requires full transmission diagnosis

Diagnostic Steps

  1. Connect advanced scan tool capable of reading TCM-specific codes
    Expected: Retrieve secondary codes from transmission control module
    Interpretation: Secondary codes will pinpoint specific transmission component faults
  2. Inspect and record freeze frame data when code set
    Expected: Data showing vehicle speed, RPM, gear and operational conditions
    Interpretation: Useful to correlate fault conditions with driving behavior
  3. Check transmission fluid level and condition
    Expected: Fluid should be clean and at proper level
    Interpretation: Low/dirty fluid suggests maintenance issue possibly causing transmission faults
  4. Perform visual inspection of wiring and connectors to TCM and transmission sensors
    Expected: No corrosion, breaks, or loose connections
    Interpretation: Any wiring issue may cause communication faults resulting in P0700
  5. Test individual transmission sensors and solenoids based on retrieved secondary codes
    Expected: Proper sensor readings and solenoid resistances
    Interpretation: Out-of-spec readings identify specific component issues requiring repair

Repair Solutions

Correct underlying fault identified by secondary TCM codes (e.g., solenoid replacement, sensor repair) medium
Estimated Cost: $150 - $1200

Cost varies widely based on specific component and labor involved

Transmission fluid change or top-off easy
Estimated Cost: $100 - $250

Basic maintenance that may resolve issues if fluid-related

Repair/replace damaged wiring or connectors medium
Estimated Cost: $50 - $300

Electrical repairs often less expensive but require careful tracing

Replace transmission control module (TCM) medium
Estimated Cost: $400 - $1000

Only if TCM confirmed faulty after diagnostics

Transmission rebuild or replacement hard
Estimated Cost: $1500 - $4000

Required for severe internal transmission failures

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Engine misfire or general engine issue incorrectly assumed as transmission malfunction

Frequently Asked Questions

What does the P0700 code mean?

When your OBD-II scanner reads P0700, it means: Transmission Control System Malfunction. This code is related to the vehicle's Engine Mechanical.

How serious is the P0700 code?

You should treat P0700 as a medium issue. May cause poor shifting, limp mode, reduced performance or drivability issues depending on specific underlying transmission fault

Common signs of the P0700 error code

You may experience the following: Check Engine Light illuminated, Poor or erratic transmission shifting, Transmission slipping or delayed engagement.

What causes the P0700 code?

This code is frequently triggered by: Transmission control module (TCM) detected internal fault and set secondary code, Low or contaminated transmission fluid, Faulty transmission wiring or connectors.

Repair cost breakdown for P0700

It depends on what needs to be fixed. Transmission fluid change or top-off repairs are cheaper (~$250), while Transmission rebuild or replacement repairs are on the higher end (~$4000).

Does P0700 affect Ford, Toyota, or Honda?

This is a universal code. You might see P0700 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

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