What are the common causes of P2318?

Chafed or shorted wire in the coil G primary control circuit. Coil G primary winding shorted to ground. Corroded or loose connector at ignition coil G. Failed coil G driver inside the ECM.

Inspect the coil G primary circuit wiring and connector for chafe or corrosion. Measure resistance across the coil G primary terminals and compare to spec. Check the coil G control wire for a short to ground. Swap coil G with a known-good coil and retest. Replace ignition coil G if the fault follows the coil. Clear the code and retest.

P2318

Ignition Coil G Primary Control Circuit Low

System: Ignition and misfire (P code)
Lamp: Check Engine Light
Category: Powertrain - Ignition

What it means

P2318 means Ignition Coil G Primary Control Circuit Low.

Check these first

Chafed or shorted wire in the coil G primary control circuit
Coil G primary winding shorted to ground
Corroded or loose connector at ignition coil G
Failed coil G driver inside the ECM

What to do next

Inspect the coil G primary circuit wiring and connector for chafe or corrosion
Measure resistance across the coil G primary terminals and compare to spec
Check the coil G control wire for a short to ground
Swap coil G with a known-good coil and retest
Replace ignition coil G if the fault follows the coil
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.