Powertrain, generic (extended)

P21D3 Cylinder 5 Injector B Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P21D3 can only appear on engines with at least five cylinders and two injectors per cylinder. Documented users are Ford's dual-injection V6 and V8 engines (2.7 and 3.5 EcoBoost of the second generation, 5.0 V8 from 2018) and GM's supercharged LT5 V8. Ford defines B as the port injector; the direct injector of this cylinder is A, coded P0205. GM stores it as Type A once 20 of 25 samples fail. Ford's check is continuous above 11 V with a 5 s window. GM's LT5 injection module rates an open by the impedance seen with the driver off, 200 kOhm or more. On a V6 one bank then runs with a single weak cylinder, which fuel trims and misfire counters can reveal.

Likely causes

Open coil in the cylinder 5 port injector
Broken wire in the bank harness of the port injectors
Output stage in the engine or injection module failed

Symptoms

  • Check engine light on
  • Misfire on cylinder 5 (P0305)
  • Fuel trim of one bank shifted

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–700
Time1–3.5 h

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

Parts involved

fuel injectorinjector wiringengine control module

Related codes

P0205P21E4P21E5P21D2P21D4P0305

References: fordservicecontent.com, gsi.ext.gm.com, en.wikipedia.org.