Powertrain, generic (extended)

P2318 Ignition Coil G Primary Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2318 says the command wire of coil G, cylinder 7, is touching ground, so it only occurs on V8, V10 or V12 engines. GM's 2019 table for the 5.3-litre L84 truck V8 lists it as a Type B code (50 of 63 failed samples, battery above 11 V, MIL after two trips). Ford covers the series up to P2327 for its V10 and adds that the PCM cuts the injector of the affected cylinder; special service message 52455 (2024) for the 6.8 and 7.3-litre petrol engines in Super Duty, F-53/F-59, E-Series and F-650/750 trucks names P2318 among codes the PCM may pin on the wrong cylinder, so a power balance test should confirm which cylinder really drops out. Open-circuit faults on coil G use P0357, misfire on cylinder 7 is P0307.

Likely causes

Coil G (cylinder 7) defective
Water or corrosion at the coil G connector
Control wire of coil G grounded by heat or chafing damage
PCM cylinder mapping error on Ford 6.8/7.3 (SSM 52455)

Symptoms

  • Check engine light on
  • Misfire on cylinder 7
  • V8 runs noticeably rough, power reduced

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–400
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ignition coilcoil driverignition wiring

Related codes

P2319P0357P2315P2321P0307

References: gsi.ext.gm.com, static.nhtsa.gov, newtonnet.co.uk, fordservicecontent.com.