What does P0357 mean?

Ignition Coil G Primary/Secondary Circuit Malfunction Engine misfire, rough idle, loss of power, and potential hesitation or stall under load

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Overview

P0357 diagnostic trouble code indicates a malfunction in the primary or secondary circuit for ignition coil G (typically cylinder #7) in the ignition system, often due to wiring issues, coil failure, or PCM driver faults.

Common Symptoms

Check engine light (MIL) illumination
Engine misfire on related cylinder
Rough idle
Poor acceleration or performance
Increased fuel consumption
Potential hesitation or stall

Most Common Causes

Faulty ignition coil G high

Primary cause across multiple sources; coil fails to generate proper spark due to internal windings failure or insulation breakdown.

Open or short in ignition coil driver wiring high

Circuit open or shorted to voltage/ground between PCM and ignition coil can trigger P0357.

Poor connection or damaged connector at coil medium

Corroded, loose, or damaged connectors can cause intermittent or failed signals.

Faulty Powertrain Control Module (PCM) coil driver medium

Rare but documented cause; internal PCM transistor failure controlling coil circuit.

Diagnostic Steps

Use an OBD-II scan tool to confirm P0357 and note related codes

Expected: Code P0357 present; possible misfire codes for cylinder 7

Interpretation: Confirms the diagnostic target and checks for related misfire events
Visually inspect wiring harness and connectors for ignition coil G

Expected: No broken wires, no corrosion, connectors seated properly

Interpretation: Identifies obvious physical circuit issues
Measure continuity and resistance of ignition coil primary and secondary circuits with multimeter

Expected: Resistance within manufacturer specifications; continuity present

Interpretation: Validates coil integrity and absence of open circuits
Swap coil G with another known good coil from a different cylinder

Expected: P0357 follows coil to new cylinder or clears

Interpretation: Verifies if the coil itself is defective
Test PCM driver output signal to coil using scope or multimeter

Expected: Appropriate pulsing ground signal present when cranking

Interpretation: Checks for PCM driver functionality

Repair Solutions

Replace faulty ignition coil G easy

Estimated Cost: $80 - $250

Often resolves the issue if coil internal failure is confirmed

Repair wiring harness or damaged connectors medium

Estimated Cost: $50 - $150

Repair open/short circuits between PCM and coil

Replace or reflash PCM hard

Estimated Cost: $300 - $1200

Only after confirming wiring/coils are OK; dealer-level programming may be required

Common Misdiagnoses

Avoid these common diagnostic mistakes:

Assuming spark plug fault without testing coil/wiring

Frequently Asked Questions

Technical definition of P0357 OBD-II Code

Technically, the P0357 code represents Ignition Coil G Primary/Secondary Circuit Malfunction. It usually points to a fault within the Ignition.

Reflecting on severity: How bad is P0357?

The P0357 code is considered medium severity. Engine misfire, rough idle, loss of power, and potential hesitation or stall under load

What are the symptoms of P0357?

You may experience the following: Check engine light (MIL) illumination, Engine misfire on related cylinder, Rough idle.

Why is my car throwing a P0357 code?

The most common causes are: Faulty ignition coil G, Open or short in ignition coil driver wiring, Poor connection or damaged connector at coil.

Estimated repair costs for different causes of P0357

Expect to pay around $150 if the issue is a Repair wiring harness or damaged connectors, but up to $1200 if the Replace or reflash PCM needs replacement.

What cars are affected by the P0357 code?

Yes, P0357 is a generic code that applies to all OBD-II compliant vehicles, including Ford, Toyota, Honda, Chevrolet, Nissan, Dodge, BMW, and more.

P0357: Ignition Coil G Primary/Secondary Circuit Malfunction