AutoCodes – Ford – P1278 Ford

P1278 Ford Code - Cylinder #8 High To Low Side Open

Quick Answer

The Injector Driver Module (IDM) is capable of detecting individual injectors open and shorts to either ground or power while the engine is running. Common causes include Faulty Fuel Injector, Faulty Injector Driver Module (IDM), Fuel Injector 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: P1278 Ford indicates Cylinder #8 High To Low Side Open.
Common causes: Common causes include Faulty Fuel Injector, Faulty Injector Driver Module (IDM), Fuel Injector 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 16,742

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 03, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1278 Ford Description

The Injector Driver Module (IDM) is capable of detecting individual injectors open and shorts to either ground or power while the engine is running. The Injector Driver Module is also capable of detecting right or left bank high side circuit opens or shorts to ground. The Diagnostic Trouble Code (DTC) indicates a low side-to-high side open in the circuit between the Injector Driver Module and the injector.

OBDII Code P1278 Ford - Cylinder #8 High To Low Side Open - AutoCodes.com — P1278 Ford Code - Cylinder #8 High To Low Side Open

What does this mean?

What are the Possible Causes of the DTC P1278 Ford?

Faulty Fuel Injector
Faulty Injector Driver Module (IDM)
Fuel Injector harness is open or shorted
Fuel Injector circuit poor electrical connection

How to Fix the DTC P1278 Ford?

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

Check valve cover wire harness connections first, including under the valve cover.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1278 Ford 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.