AutoCodes – Generic – P109D

P109D Code - Short in Fuel Pressure Switching Valve Circuit

Quick Answer

A Flexible Fuel Vehicle (FFV) can be used with a fuel containing a high concentration of ethyl alcohol. Common causes include Faulty Fuel Pressure Switching Valve, Fuel Pressure Switching Valve harness is open or shorted, Fuel Pressure Switching Valve 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: P109D indicates Short in Fuel Pressure Switching Valve Circuit.
Common causes: Common causes include Faulty Fuel Pressure Switching Valve, Fuel Pressure Switching Valve harness is open or shorted, Fuel Pressure Switching Valve 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 3,150

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 Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P109D Description

A Flexible Fuel Vehicle (FFV) can be used with a fuel containing a high concentration of ethyl alcohol.
This FFV uses a fuel pressure switching system which changes the fuel pressure to low or high using a fuel pressure switching valve.
The code is stored when a malfunction is detected in the fuel pressure switching valve circuit. If the voltage of the fuel pressure switching valve circuit is different from the voltage commanded by the Engine Control Module (ECM), the ECM determines that the fuel pressure switching valve circuit is open or shorted, and stores a DTC.

OBDII Code P109D - Short in Fuel Pressure Switching Valve Circuit - AutoCodes.com — P109D Code - Short in Fuel Pressure Switching Valve Circuit

What does this mean?

What are the Possible Causes of the DTC P109D?

Faulty Fuel Pressure Switching Valve
Fuel Pressure Switching Valve harness is open or shorted
Fuel Pressure Switching Valve circuit poor electrical connection
Faulty F/PMP VSV relay
Faulty Engine Control Module (ECM)

How to Fix the DTC P109D?

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 P109D 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.

Need more information about the P109D code?

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Information for Specific Makes

P109D Lexus — Short in Fuel Pressure Switching Valve Circuit
P109D Toyota — Short in Fuel Pressure Switching Valve Circuit

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.