P0354 — Ignition Coil D Primary Control Circuit
P0354 is the primary control circuit fault for ignition coil D (typically cylinder 4). Continue the same proven swap-test method used for P0351–P0353. On 4-cylinder engines this is often the rear cylinder — access may be tighter. Check for oil in the plug well before installing a new coil.
Fault Overview
Failed coil, wiring issues, connector problems, and power/ground faults are the primary causes.
Engine & Platform Coverage
Symptoms
- •P0354
- •ignition coil D circuit
- •coil primary cylinder 4
Possible Causes
- 1.Failed ignition coil D
- 2.Wiring issues
- 3.Connector problems
- 4.Power or ground faults
Wiring & Circuit Notes
Coil D circuit.
DVOM Specs & Sensor Tests
Primary resistance and control circuit tests.
Diagnostic Flow — FSM Sequence
AI Diesel Tech enforces this evidence-gate sequence. Each gate must pass before advancing.
3 steps locked behind Technician Mode- 1Step 1 — Swap the Coil with Another Cylinder: Swap coil D with another cylinder and retest. If the code or misfire follows the coil, replace it.
- 2Step 2 — Test the Circuit: Test the control circuit voltage, power feed, and ground at the coil connector.
- 3Step 3 — Inspect Connector and Wiring: Inspect the connector and wiring for oil intrusion, corrosion, or damage.
- 4Step 4 — Replace if Needed: Replace the coil if it fails the swap test and the circuit is proven good.
Unlock the full evidence-gated diagnostic sequence, DVOM test steps, and repair procedures in Technician Mode.
Full Diagnostic Access
Verification steps, preventative measures, severity guidance, and legacy comparison are available in Technician Mode.
Typical Repair Costs
Replace coil $40–200; repair wiring $50–200.
Related Codes & Pages
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Summary
Use the AI Diesel Tech diagnostic engine to run this code through a structured, evidence-gated sequence and get a confirmed root cause before any parts are replaced.