OBD Guide

P078F

Transmission Mode Switch C Circuit

P078F is an OBD-II diagnostic trouble code meaning: Transmission Mode Switch C Circuit. Common causes: transmission mode switch malfunction, open or short circuit in the circuit. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Delayed gear shifting
  • The transmission goes into emergency mode
  • Inability to switch between modes
  • Check Engine Light Is On
  • Loss of engine power

Causes

  • Transmission mode switch malfunction
  • Open or short circuit in the circuit
  • Poor contact in connectors
  • Wiring harness damage
  • Problems with the transmission control unit

How to Fix

  1. Check the continuity of the switch circuit
  2. Inspect connectors and contacts for corrosion
  3. Test the mode switch with a multimeter
  4. Check circuit resistance
  5. If necessary, replace the mode switch

Related codes

Error P078F by Vehicle Brand

FAQ

What does the P078F code mean?

P078F is an OBD-II diagnostic trouble code that indicates: Transmission Mode Switch C Circuit

What causes a P078F error code?

The most common causes of P078F include: Transmission mode switch malfunction; Open or short circuit in the circuit; Poor contact in connectors; Wiring harness damage.

How do I fix a P078F diagnostic trouble code?

To fix P078F: Check the continuity of the switch circuit. Inspect connectors and contacts for corrosion. Test the mode switch with a multimeter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P078F?

Limited driving only, diagnose soon

How much does it cost to fix P078F?

The estimated repair cost for P078F is $17–56. Actual cost depends on your vehicle, location, and labor rates.

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