Powertrain, generic (extended)

P2305 Ignition Coil B Secondary Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2305 is about coil B's output side: the secondary winding, the connection to the plug and the spark plug of cylinder 2. Where a maker uses it, the module does not just watch whether the coil was switched, but whether a usable spark happened. Ion sensing is one way: as with Saab's Direct Ignition, a low voltage is applied across the plug outside the firing moment, and the resulting ion current tells the module whether the mixture burned – it can even replace the knock sensor. FCA names P2305 coil 2 secondary circuit with insufficient ionization on 2015–2016 Caravan and Town & Country 3.6 V6 and listed it with P0300–P0306 when misfire, rough running and the MIL called for a new PCM. Unlike P2303/P2304, a clean control line does not rule this code out; spark plugs and boots come first.

Likely causes

Spark plug of cylinder 2 worn, oily or with the wrong gap
Coil B boot cracked or damp, spark leaking away
Coil B secondary winding weak
Faulty ion-current evaluation in the PCM

Symptoms

  • Check engine light on
  • Misfire on cylinder 2, sometimes only under load
  • Rough running, raised fuel consumption

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–900
Time0.3–3 h

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

Parts involved

ignition coilspark plugspark plug wire

Related codes

P2303P2304P2302P0302P0352

References: static.nhtsa.gov, en.wikipedia.org, law.cornell.edu.