Powertrain, generic (extended)

P21D0 Cylinder 2 Injector B Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P21D0 is the open-circuit code for the B injector of cylinder 2. Where that cylinder sits varies: GM's small-block V8 alternates odd and even numbers between the banks, so cylinder 2 opens the right bank, while Ford's V6 and V8 count one bank first and place it next to cylinder 1. Ford defines B as the port injector, the direct injector being A with P0202. Ford runs the check in every engine with combined port and direct injection, from the three-cylinder 1.5 to the 5.0 V8, continuously at 11 V or more for 5 s. GM's LT5 injection module samples the circuit every 100 ms once the powertrain relay supplies at least 11 V. On engines that run on port fuel alone at light load, like Ford's second 3.5 EcoBoost, the cylinder then misfires mostly at idle. Low and high faults are P21DE and P21DF.

Likely causes

Port injector of cylinder 2 with an open winding
Broken wire or pushed-back terminal in the injector harness
Output stage in the engine or injection module failed

Symptoms

  • Check engine light on
  • Misfire on cylinder 2, mainly at idle and light load
  • Code P0302 stored as well

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 h

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

Parts involved

fuel injectorinjector wiringengine control module

Related codes

P0202P21DEP21DFP21CFP21D1P0302

References: fordservicecontent.com, en.wikipedia.org, static.nhtsa.gov.