AutoCodes – Ford – P0109 1999 Ford F150

P0109 1999 Ford F150 Code - BARO Sensor Circuit Intermittent

Quick Answer

The Manifold Absolute Pressure (MAP) sensor measures the pressure inside the intake manifold. Common causes include Faulty Manifold Absolute Pressure (MAP) Sensor, Manifold Absolute Pressure Sensor harness is open or shorted, Manifold Absolute Pressure Sensor circuit poor electrical connection. 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: P0109 1999 Ford F150 indicates BARO Sensor Circuit Intermittent .
Common causes: Common causes include Faulty Manifold Absolute Pressure (MAP) Sensor, Manifold Absolute Pressure Sensor harness is open or shorted, Manifold Absolute Pressure Sensor circuit poor electrical connection.
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 3,508

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 20, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0109 1999 Ford F150 Description

The Manifold Absolute Pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, Barometric Pressure (BARO) and if equipped, turbocharger output. A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance.
The MAP sensor wiring includes 3 circuits. The Engine Control Module (ECM) supplies a regulated 5 volts to the sensor on a 5 V reference circuit. The ECM supplies ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.
Under normal operation the greatest pressure that can exist in the intake manifold is at ignition ON, engine OFF, which is equal to the BARO. The lowest manifold pressure occurs when the vehicle is idling or decelerating. The ECM monitors the MAP sensor signal for pressure outside of the normal range.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the MAP Sensor voltage is failing intermittently.

OBDII Code P0109 1999 Ford F150 - BARO Sensor Circuit Intermittent - AutoCodes.com — P0109 1999 Ford F150 Code - BARO Sensor Circuit Intermittent

What does this mean?

What are the Possible Causes of the DTC P0109 1999 Ford F150?

Faulty Manifold Absolute Pressure (MAP) Sensor
Manifold Absolute Pressure Sensor harness is open or shorted
Manifold Absolute Pressure Sensor circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0109 1999 Ford F150?

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 does this mean?

Code Tech Notes

The sensor signal to the PCM is failing intermittently.
Check harness and connection.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0109 1999 Ford F150 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 P0109 1999 Ford F150 Code

1. What are common symptoms of OBDII code P0109 on a 1999 Ford F150?

- Common symptoms include poor engine performance, rough idle, decreased fuel efficiency, and stalling.

2. What does the OBDII code P0109 for a 1999 Ford F150 indicate?

- OBDII code P0109 indicates an issue with the BARO (barometric pressure) sensor circuit, specifically an intermittent fault.

3. What are possible causes of the BARO Sensor Circuit Intermittent code P0109 on a 1999 Ford F150?

- Possible causes include a faulty BARO sensor, damaged wiring or connectors in the sensor circuit, or a problem with the engine control module (ECM).

4. How can I diagnose the BARO Sensor Circuit Intermittent OBDII code P0109 on my 1999 Ford F150?

- Diagnose the issue by checking the BARO sensor wiring and connectors for damage, testing the sensor's operation, and using a scan tool to monitor sensor data.

5. Can a dirty air filter trigger the P0109 code on a 1999 Ford F150?

- Yes, a dirty air filter can disrupt the proper operation of the BARO sensor and potentially trigger the P0109 code.

6. How can I repair the BARO Sensor Circuit Intermittent code P0109 on my 1999 Ford F150?

- Repair options include replacing the BARO sensor, repairing damaged wiring or connectors, and resetting the ECM after addressing the issue.

7. Is it safe to continue driving with the OBDII code P0109 on a 1999 Ford F150?

- It is not recommended to drive with the P0109 code present, as it can lead to further engine damage and worsened performance if left unresolved.

8. Can extreme weather conditions affect the BARO Sensor Circuit Intermittent code P0109 on a 1999 Ford F150?

- Yes, extreme weather conditions such as high altitudes or severe temperature changes can impact the BARO sensor's readings and trigger the P0109 code.

9. How much does it typically cost to repair the BARO Sensor Circuit Intermittent code P0109 on a 1999 Ford F150?

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

10. Can resetting the ECM clear the P0109 code on a 1999 Ford F150?

- Resetting the ECM may temporarily clear the code, but it is essential to diagnose and repair the underlying issue to prevent the code from reoccurring.