AutoCodes – Lincoln – C109F Lincoln

C109F Lincoln Code - Vacuum Sensor Signal Fault

Quick Answer

The vacuum sensor is used by the Anti-Lock Brake System (ABS) Module to determine if hydraulic pump intervention is necessary due to loss of vacuum in the booster. Common causes include Loose Brake Booster Vacuum Hose, Faulty Brake Booster Vacuum Sensor, Brake Booster Vacuum Sensor harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: C109F Lincoln indicates Vacuum Sensor Signal Fault.
Common causes: Common causes include Loose Brake Booster Vacuum Hose, Faulty Brake Booster Vacuum Sensor, Brake Booster Vacuum Sensor harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,321

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C109F Lincoln Description

The vacuum sensor is used by the Anti-Lock Brake System (ABS) Module to determine if hydraulic pump intervention is necessary due to loss of vacuum in the booster. The ABS module sends a 5-volt reference voltage to the sensor, the sensor compares the pressure in the booster to the ambient air pressure in the engine compartment and sends a varying voltage back to the ABS module based on the difference between the pressures. Normally, the pressure in the booster is much lower than ambient air pressure. As the pressure in the booster gets higher (closer to matching ambient air pressure), the lower the voltage sent back to the ABS module becomes.
When the vacuum in the brake booster falls below a predetermined level, the ABS module will command the hydraulic pump motor to activate on the next (and any subsequent) brake pedal application to assist with vehicle braking. The ABS module will continue to use the pump motor for braking assist as long as the low vacuum condition exists.

OBDII Code C109F Lincoln - Vacuum Sensor Signal Fault - AutoCodes.com — C109F Lincoln Code - Vacuum Sensor Signal Fault

What does this mean?

What are the Possible Causes of the DTC C109F Lincoln?

Loose Brake Booster Vacuum Hose
Faulty Brake Booster Vacuum Sensor
Brake Booster Vacuum Sensor harness is open or shorted
Brake Booster Vacuum Sensor circuit poor electrical connection

How to Fix the DTC C109F Lincoln?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C109F Lincoln code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C109F Lincoln Code

1. What are the common symptoms of OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- Common symptoms include rough idling, engine stalling, decreased fuel efficiency, and the Check Engine Light illuminating.

2. What causes the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- The code is typically triggered by a faulty vacuum sensor, vacuum leak, wiring issue, or a problem with the engine's vacuum system.

3. How can I diagnose the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- You can diagnose the code by using an OBDII scanner to retrieve the fault code, inspecting the vacuum hoses and sensor for any damage, and testing the sensor's functionality.

4. What are some repair tips for fixing the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- Repair tips include checking and replacing damaged vacuum hoses, testing the vacuum sensor for proper operation, and ensuring all connections are secure and free from debris.

5. Can I drive my vehicle with the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault) active?

- It is not recommended to drive your vehicle with this fault code active, as it can lead to further engine issues and potential breakdowns.

6. How much does it typically cost to repair the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- The cost of repair can vary depending on the extent of the issue, but it may range from $100 to $300 for parts and labor.

7. Is the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault) a serious issue?

- While the code may not cause immediate harm to your vehicle, ignoring it can lead to decreased performance and potential long-term damage to the engine.

8. Can I reset the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault) with a simple reset tool?

- You can reset the code with an OBDII scanner or by disconnecting the vehicle's battery for a few minutes, but the issue causing the code will need to be addressed for it not to reappear.

9. How long does it take to repair the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault)?

- The repair time can vary depending on the exact cause of the fault, but it may take anywhere from 1 to 3 hours to diagnose and fix the issue.

10. Can a DIY enthusiast fix the OBDII code C109F Lincoln (Vacuum Sensor Signal Fault) at home?

- Depending on the individual's mechanical skills and access to tools, some DIY enthusiasts may be able to address the issue at home by following repair guides and instructions.