AutoCodes – Mercury – P2304 Mercury

P2304 Mercury Code - Ignition Coil 'B' Primary Control Circuit High

Quick Answer

The current flow, or dwell, through the primary ignition coil is controlled by the Powertrain Control Module (PCM) by providing a switched ground path through the ignition coil driver to ground. Common causes include Faulty Ignition Coil 'B', Ignition Coil 'B' harness is open or shorted, Ignition Coil 'B' 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: P2304 Mercury indicates Ignition Coil 'B' Primary Control Circuit High.
Common causes: Common causes include Faulty Ignition Coil 'B', Ignition Coil 'B' harness is open or shorted, Ignition Coil 'B' 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 1,280

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
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Code P2304 Mercury Description

The current flow, or dwell, through the primary ignition coil is controlled by the Powertrain Control Module (PCM) by providing a switched ground path through the ignition coil driver to ground. When the ignition coil driver is switched on, current rapidly builds up to a maximum value, determined by the coil inductance and resistance. When the current is switched off, the magnetic field collapses which induces a secondary high voltage surge and the spark plug is fired. This high voltage surge creates a flyback voltage which the PCM uses as a feedback during the ignition diagnostics. The PCM continuously monitors the ignition system for concerns. The P2304 code sets when the PCM detects a short to voltage in the circuit.

OBDII Code P2304 Mercury - Ignition Coil 'B' Primary Control Circuit High - AutoCodes.com — P2304 Mercury Code - Ignition Coil 'B' Primary Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P2304 Mercury?

Faulty Ignition Coil 'B'
Ignition Coil 'B' harness is open or shorted
Ignition Coil 'B' circuit poor electrical connection

How to Fix the DTC P2304 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 P2304 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.