AutoCodes – Lincoln – P1390 Lincoln

P1390 Lincoln Code - Octane Adjust Out of Self-Test Range

Quick Answer

The Octane Adjust (OCT ADJ) shorting bar is used to retard spark timing. Common causes include Damage or missing Octane Adjust (OCT ADJ) cap. 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: P1390 Lincoln indicates Octane Adjust Out of Self-Test Range.
Common causes: Common causes include Damage or missing Octane Adjust (OCT ADJ) cap.
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 1,517

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 17, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1390 Lincoln Description

The Octane Adjust (OCT ADJ) shorting bar is used to retard spark timing. Removal of the shorting bar from the in-line connector will typically retard spark three degrees.
The purpose of the OCT ADJ self-test is to check the state of the OCT ADJ shorting bar. A Diagnostic Trouble Code (DTC) will be present if the shorting bar is removed or if there is an open circuit. The OCT ADJ shorting bar is similar in shape to the SPOUT in-line connector. On some applications the Power Steering Pressure (PSP) circuit will also have a similar shorting bar connector. DO NOT remove the shorting bar unless directed by a Technical Service Bulletin (TSB).
If you don't have the bar, your timing has been retarded.

OBDII Code P1390 Lincoln - Octane Adjust Out of Self-Test Range - AutoCodes.com — P1390 Lincoln Code - Octane Adjust Out of Self-Test Range

What does this mean?

What are the Possible Causes of the DTC P1390 Lincoln?

Damage or missing Octane Adjust (OCT ADJ) cap

How to Fix the DTC P1390 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 P1390 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.