Powertrain, generic (extended)

P2309 Ignition Coil D Primary Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2309 stands for a grounded control lead to coil D – cylinder 4, which on a four-cylinder engine is the last coil in the row. In 2023 FCA released bulletins 18-022-23 and 18-023-23 for the Alfa Romeo Giulia and Stelvio with the 280 hp 2.0 turbo: P2300-00, P2303-00, P2306-00 and P2309-00 could set together with an EVAP purge code, and the remedy was PCM software rather than parts. On Ford petrol engines of 2020–2023 the coil codes P2300 to P2310 are among the faults that block automatic engine stop-start. On Saab's LDK-engined 9-5 of 2010 the same code needs 4 s of continuous or 50 s of cumulative short and is Type B. When all four low codes appear at once, suspect software or a shared harness section before replacing coils.

Likely causes

Coil D (cylinder 4) defective
PCM software fault setting several coil low codes (FCA 2.0 turbo 2023)
Damaged harness section carrying several coil lines
Poor contact or moisture at the coil D connector

Symptoms

  • Check engine light on
  • Misfire on cylinder 4
  • Auto stop-start no longer works (Ford)
  • Reduced power

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

P2310P2311P0354P2306P0304

References: static.nhtsa.gov, static.nhtsa.gov, fordservicecontent.com, saabwisonline.com.