Obdaryn

P21D1Cylinder 3 Injector B Circuit/Open

  • Generic OBD-II code · Powertrain
  • Turns on the check-engine light
  • Matters for the ITP
How the car detects it
P21D1 concerns the B injector of cylinder 3, which on Ford's 1.5 EcoBoost three-cylinder is the last one in the block. That engine combines port and direct fuel, and Ford names the port injectors B. Bulletin SSM 49996 for the 2021 Bronco Sport describes P21CF, P21D0 and P21D1 appearing together with transmission and other codes, in some cases with a no-crank condition, because the harness was damaged at the transmission cover; when all three B codes show at once, a shared wiring fault is far more likely than three bad injectors. Ford's summary checks the B circuits continuously above 11 V within 5 s. GM's LT5 V8 module flags an open low side once 20 of 25 samples fail. The direct injector of the cylinder is coded P0203.
What you may notice
  • Check engine light on
  • Rough running or misfire on cylinder 3
  • With harness damage also transmission codes or no crank
Likely causes
  • LikelyHarness damage affecting several injectors at once (Ford Bronco Sport, transmission cover)
  • PossibleOpen coil in the cylinder 3 port injector
  • RareConnector not latched or corroded
Inspection (ITP)
Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
Repair
Medium · Usually a job for a workshop.Typical cost: €80 – €600

Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.