OBD Guide

P078C

Shift Timing Solenoid B Low

P078C is an OBD-II diagnostic trouble code meaning: Shift Timing Solenoid B Low. Common causes: open or short circuit in solenoid circuit, shift solenoid malfunction. Estimated repair cost: $17–56.

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

Symptoms

  • Incorrect gear shifting
  • The gearbox goes into emergency mode
  • Delays when shifting gears
  • Jerking when switching
  • Check Engine light comes on

Causes

  • Open or short circuit in solenoid circuit
  • Shift solenoid malfunction
  • Connector problems or contact corrosion
  • Transmission control module (TCM) malfunction
  • Circuit power problems

How to Fix

  1. Check continuity of solenoid B
  2. Check solenoid resistance
  3. Inspect connectors and contacts for corrosion
  4. Check power supply to solenoid circuit
  5. Replace solenoid B if necessary

Related codes

Error P078C by Vehicle Brand

FAQ

What does the P078C code mean?

P078C is an OBD-II diagnostic trouble code that indicates: Shift Timing Solenoid B Low

What causes a P078C error code?

The most common causes of P078C include: Open or short circuit in solenoid circuit; Shift solenoid malfunction; Connector problems or contact corrosion; Transmission control module (TCM) malfunction.

How do I fix a P078C diagnostic trouble code?

To fix P078C: Check continuity of solenoid B. Check solenoid resistance. Inspect connectors and contacts for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P078C?

Limited driving only, diagnose soon

How much does it cost to fix P078C?

The estimated repair cost for P078C is $17–56. Actual cost depends on your vehicle, location, and labor rates.

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