Faulty ignition coil C with an open or shorted primary winding, which is the most common cause on Ford engines; Damaged or corroded electrical connector at coil C, including backed-out terminals or water intrusion; Chafed, broken, or shorted wire in the coil C primary circuit between the PCM and the coil; Failed PCM driver for that specific coil circuit, though this is less common than coil or wiring faults; Poor ground connection for the coil or engine block that raises primary circuit resistance; Aftermarket coil or spark plug of incorrect specification causing abnormal primary current draw; Oil or coolant contamination reaching the coil primary connector and degrading the circuit

DTC codes / Ford codes / P1354

P1354 · FordIgnition Coil C Primary Circuit Fault

Q: What does code P1354 mean?

Ignition Coil C Primary Circuit Fault. P1354 on Ford vehicles means the powertrain control module (PCM) detected an abnormal condition in the primary circuit of ignition coil C, which is the low-voltage side that the PCM uses to trigger the coil. The PCM monitors the coil driver circuit for expected voltage changes when the coil is commanded on and off, and it sets this code when the feedback does not match what the software expects.

P1354 on Ford vehicles means the powertrain control module (PCM) detected an abnormal condition in the primary circuit of ignition coil C, which is the low-voltage side that the PCM uses to trigger the coil. The PCM monitors the coil driver circuit for expected voltage changes when the coil is commanded on and off, and it sets this code when the feedback does not match what the software expects.

SystemPowertrain

Code typeFord specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Check engine light or service engine soon light illuminated, often with no other symptoms besides the warning light
Engine misfire or rough running, especially under load or at idle, if the coil is not firing consistently
Noticeable loss of power or hesitation during acceleration when the affected cylinder drops out
Shaking or vibration felt through the steering wheel or seat that follows engine speed
A flashing check engine light in severe cases where the misfire could damage the catalytic converter
Slightly rough idle that smooths out at higher engine speeds if the coil is marginal rather than dead

Common causes, most likely first

Faulty ignition coil C with an open or shorted primary winding, which is the most common cause on Ford engines
Damaged or corroded electrical connector at coil C, including backed-out terminals or water intrusion
Chafed, broken, or shorted wire in the coil C primary circuit between the PCM and the coil
Failed PCM driver for that specific coil circuit, though this is less common than coil or wiring faults
Poor ground connection for the coil or engine block that raises primary circuit resistance
Aftermarket coil or spark plug of incorrect specification causing abnormal primary current draw
Oil or coolant contamination reaching the coil primary connector and degrading the circuit

How to diagnose and fix it

Scan all modules and record freeze-frame data for P1354, then check for related misfire codes to confirm which cylinder coil C serves on this Ford engine
Inspect the coil C electrical connector and primary wiring for corrosion, chafing, or loose terminals, and repair any damage found
Swap coil C with a known-good coil from another cylinder and clear the code to see whether the fault follows the coil or stays with the circuit
Measure primary winding resistance of coil C with a multimeter and compare it to the specification for your engine
Backprobe the coil C primary control wire at the PCM and at the coil to check for continuity and to confirm the PCM is commanding the coil on and off
Check coil and engine ground connections for voltage drop under load, cleaning and tightening any suspect grounds
Replace the ignition coil if testing confirms a faulty primary winding, then clear codes and verify the repair with a road test that includes load

What Ford coil C faults really mean

On many Ford engines coil C does not correspond to cylinder 3, so always confirm the coil lettering or cylinder mapping in the service information before replacing a coil.
A P1354 can be set by a marginal coil that still fires at idle but breaks down under load, so a simple resistance check may pass while the coil is still faulty.
The PCM driver for coil C can be damaged by a shorted coil primary, so replacing a coil without checking the control wire can lead to a repeat failure.
Water intrusion into the coil connector or spark plug well is a common Ford-specific cause that is missed when only the coil itself is inspected.
A loose or corroded ground strap between the engine and chassis can set coil primary circuit codes on multiple coils and mimic a failed PCM.

Can I keep driving with P1354?

You can usually drive a Ford with P1354 if the engine runs smoothly and the light is steady, but avoid heavy acceleration and long trips until it is diagnosed. If the check engine light flashes or the engine misfires badly, stop driving because raw fuel can overheat and destroy the catalytic converter.

Tools that help

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Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.