OBD Guide

C109F

Vacuum Sensor Signal Fault

C109F is an OBD-II diagnostic trouble code meaning: Vacuum Sensor Signal Fault. Common causes: vacuum sensor malfunction, open or short circuit in wiring harness. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Unstable engine operation at idle
  • Increased fuel consumption
  • Check Engine Light Illuminates
  • Problems with the brake system (if the sensor is connected to it)

Causes

  • Vacuum sensor malfunction
  • Open or short circuit in wiring harness
  • Poor contact in connectors
  • Leaks in vacuum lines
  • Blockages in vacuum lines

How to Fix

  1. Check the integrity of the vacuum sensor wiring harness and connectors
  2. Check the vacuum sensor for malfunctions
  3. Check vacuum lines for leaks and blockages
  4. Replace the vacuum sensor if necessary
  5. Clean or replace vacuum lines if problems are found

Related codes

FAQ

What does the C109F code mean?

C109F is an OBD-II diagnostic trouble code that indicates: Vacuum Sensor Signal Fault

What causes a C109F error code?

The most common causes of C109F include: Vacuum sensor malfunction; Open or short circuit in wiring harness; Poor contact in connectors; Leaks in vacuum lines.

How do I fix a C109F diagnostic trouble code?

To fix C109F: Check the integrity of the vacuum sensor wiring harness and connectors. Check the vacuum sensor for malfunctions. Check vacuum lines for leaks and blockages. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C109F?

Limited driving only, diagnose soon

How much does it cost to fix C109F?

The estimated repair cost for C109F is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat