AutoCodes – Mercury – P1246 Mercury

P1246 Mercury Code - Alternator Load Input Failed

Quick Answer

The Powertrain Control Module (PCM) monitors generator load from the generator/regulator in the form of frequency. Common causes include Faulty Alternator/Generator, Alternator/Generator harness is open or shorted, Alternator/Generator 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: P1246 Mercury indicates Alternator Load Input Failed.
Common causes: Common causes include Faulty Alternator/Generator, Alternator/Generator harness is open or shorted, Alternator/Generator 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 2,904

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 Jul 22, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1246 Mercury Description

The Powertrain Control Module (PCM) monitors generator load from the generator/regulator in the form of frequency. The frequency range is determined by the temperature of the voltage regulator where 97% represents full load, below 6% means no load.

OBDII Code P1246 Mercury - Alternator Load Input Failed - AutoCodes.com — P1246 Mercury Code - Alternator Load Input Failed

What does this mean?

What are the Possible Causes of the DTC P1246 Mercury?

Faulty Alternator/Generator
Alternator/Generator harness is open or shorted
Alternator/Generator circuit poor electrical connection
Damaged Powertrain Control Module (PCM)

How to Fix the DTC P1246 Mercury?

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 P1246 Mercury 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.