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P0351 on Audi: Symptoms, Causes & Fix

Ignition Coil A Primary/Secondary Circuit Malfunction

Official technical diagnostic wire for fault code P0351 specifically affecting Audi vehicles (A4, A6, Q5, Q7, A3).

Sensor Voltage Ref
0.1V – 5.0V Ref
Audi Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$100 - $350 (DIY: $30 - $90)
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your Audi Model for P0351:

6 Models Available

1. Common Symptoms on Audi Vehicles

When Audi Engine Control Modules (ECM) trigger fault code P0351, drivers typically report:

Flashing Check Engine Light on Audi Powertrains
Severe engine shuddering and jerking under acceleration on Audi Powertrains
Hard misfire on Cylinder 1 (accompanied by P0301) on Audi Powertrains
Strong smell of unburned gasoline from exhaust on Audi Powertrains

2. Root Causes on Audi Engines

Historical diagnostic claims across Audi engines point to the following failure distribution:

55%
Failed ignition coil pack on Cylinder 1 (Coil A) (Audi OEM Part)
25%
Broken or melted wiring harness to ignition coil 1 (Audi OEM Part)
12%
Corroded or broken terminal pins in coil electrical connector (Audi OEM Part)
8%
Burned ignition driver transistor (IGBT) inside the ECM/PCM (Audi OEM Part)

3. Step-by-Step Fix Protocol for Audi

01
Locate Coil A (Cylinder 1 Ignition Coil)

Identify Cylinder 1 ignition coil pack mounted on the valve cover. on Audi engines.

Required Tool: Flashlight
02
Perform Coil Swap Test

Swap Coil 1 with Coil 2. Clear codes and restart engine. If code switches to P0352 (Coil B), the ignition coil is 100% defective. on Audi engines.

Required Tool: 10mm Socket, Ratchet, OBD-II Scanner
03
Test Wiring Harness if Code Remains P0351

Check for 12V battery power, chassis ground, and 5V trigger pulse from the PCM on the 3-pin / 4-pin harness plug. on Audi engines.

Required Tool: Digital Multimeter, Test Light
04
Replace Ignition Coil & Spark Plug

Install a new OEM ignition coil (e.g. Denso, Motorcraft, Delphi) and replace the spark plug on Cylinder 1. on Audi engines.

Required Tool: 5/8 Spark Plug Socket, 10mm Socket, Ratchet
05
Clear Trouble Codes and Road Test

Clear DTCs and verify smooth acceleration under load. on Audi engines.

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Audi (P0351)

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OEM Ignition Component

Direct-Fit Laser Iridium Spark Plugs (Set of 4/6)

4.8 / 5.0 (Top Rated)

Pre-gapped iridium spark plugs engineered to restore smooth combustion on Audi.

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Ignition Service Tool

Magnetic Swivel Spark Plug Socket Set

4.8 / 5.0 (Amazon Choice)

360-degree magnetic swivel socket prevents ceramic plug cracks inside deep engine spark wells.

$16.99 Prime
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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

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Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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4. Audi P0351 Frequently Asked Questions

What does code P0351 mean on a Audi?

On Audi vehicles, P0351 indicates that the Engine Control Module (ECM) detected ignition coil a primary/secondary circuit malfunction. This typically points to Failed ignition coil pack on Cylinder 1 (Coil A) or Broken or melted wiring harness to ignition coil 1.

Can I continue driving my Audi with code P0351?

No. Cylinder 1 ignition coil has failed completely, causing an active misfire and dumping unburned fuel into the catalytic converter. Because this code carries a Critical severity rating on Audi powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code P0351 on a Audi?

Estimated DIY parts cost ranges from $100 - $350 (DIY: $30 - $90), while professional shop repairs at an authorized Audi dealership or independent specialist typically range from $180 to $380 including diagnostic labor.