MazicBay Diagnostics
MAZICBAYDiagnostics
Lookup DTC
P03542021 Model Year TelemetryCritical Severity

P0354 on 2021 Honda Civic

Ignition Coil D Primary/Secondary Circuit Malfunction

Technical troubleshooting wire for fault code P0354 specifically tailored for the 2021 Honda Civic. Includes wiring sensor pinouts, freeze frame PID parameters, and step-by-step diagnostic tree.

2021 Engine Control Module (ECM) Specific Calibration
Honda Civic2021 Civic
2021 Honda Civic
Sedan • 2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid
2021 Stats
Vehicle
2021 Civic
2.0L i-VTEC (158HP) / 1.5L Turbo (180HP) / Civic Type R (315HP) / Hybrid
ECU Subsystem
Automotive OBD-II
SAE Mode $01 & $02
Est. Repair Cost
$100 - $350 (DIY: $30 - $90)
OEM Parts & DIY
Urgency Level
Critical
Tow to Shop
Switch Civic Model Year for P0354
2025P0354 Guide2024P0354 Guide2023P0354 Guide2022P0354 Guide2021P0354 Guide2020P0354 Guide2019P0354 Guide2018P0354 Guide2017P0354 Guide2016P0354 Guide2015P0354 Guide2014P0354 Guide

Common 2021 Civic Symptoms

  • Flashing CEL
  • Rough running
  • Loss of power
  • P0304 code

Likely Root Causes on 2021 Civic

  • Dead Cylinder 4 ignition coil
  • Wiring damage
  • Corroded connector

Step-by-Step Fix Protocol for 2021 Honda Civic

Step 1: Scan & Record Freeze Frame Data

Connect an OBD-II scanner to the DLC port under the driver dashboard. Record engine RPM, Short Term / Long Term Fuel Trim (STFT/LTFT), and engine coolant temperature at the moment P0354 set.

Step 2: Inspect Wiring Harness & Pin Voltages

Inspect the sensor connector on the 2021 Civic engine bay. Use a multimeter to verify reference voltage (5.0V / 12.0V) and ground continuity.

Step 3: Component Replacement & PCM Reset

Replace the verified defective component using OEM or equivalent grade parts. Clear DTC P0354 and complete an EPA drive cycle to verify readiness monitors set to READY.

Recommended Parts & Testing Tools

Equipment for Diagnosing 2021 Honda Civic (P0354)

Prime Fast Delivery & Verified Fitment
OEM Ignition Component

Direct-Fit Laser Iridium Spark Plugs (Set of 4/6)

4.8 / 5.0 (Top Rated)

Pre-gapped iridium spark plugs engineered to restore smooth combustion on 2021 Honda Civic.

$36 – $68 Prime
Check Price on Amazon
Ignition Service Tool

Magnetic Swivel Spark Plug Socket Set

4.8 / 5.0 (Amazon Choice)

360-degree magnetic swivel socket prevents ceramic plug cracks inside deep engine spark wells.

$16.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for 2021 Honda CivicVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
Find Parts on Amazon
* As an Amazon Associate, MazicBay earns from qualifying purchases. Prices & availability subject to change.
Full Reliability Report2021 Civic ProblemsSafety Recalls2021 Civic RecallsAll Generation YearsCivic P0354 Master Hub