P1352

Code

FORD P — Powertrain

Ignition Coil A Primary Circuit Fault

Brand: FORD

Type: P — Powertrain

Views: UK: 34 EN: 52 RU: 45

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Page language: EN

Causes

Failed ignition coil (open/shorted primary winding or internal driver failure)
Damaged, corroded, or loose coil connector or pins
Broken, shorted or high-resistance wiring between coil and PCM (open to ground or power, short to battery, short to ground)
Blown fuse or faulty ignition power relay supplying coil
Poor battery voltage or charging system problem
Faulty PCM/ECM ignition driver (less common)

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough idle or engine misfire at idle
Engine hesitation or reduced power under load
Reduced fuel economy
Hard starting or extended crank time
Possible engine stalling or backfiring

What to check

Retrieve codes and freeze-frame data with a scan tool; note related misfire codes (P0301 etc.)
Visually inspect coil A and connector for corrosion, oil, melted insulation or bent pins
Check battery voltage and charging system; verify supply voltage at ignition circuit
Inspect fuses and ignition relays related to coil power
Compare with known-good coil by swapping with another cylinder (if coil pack type) to see if code follows coil
Wiggle-test wiring/connectors while monitoring code or misfire to detect intermittent faults

Signal parameters

Primary DC resistance: typically low (example ranges ~0.2–2.0 Ω) — value varies by coil; consult OEM spec
Secondary resistance: commonly several kilo-ohms (example ~5–20 kΩ) — consult OEM spec
Supply voltage at coil primary (key ON/crank): approx. battery voltage (~11–14.5 V)
Coil driver: PCM pulses to ground (primary waveform shows pulsed ground/dwell); expected switching edges and ring on oscilloscope
Dwell/pulse duration during cranking/idle: manufacturer-specific (example 2–7 ms); check OEM timing
Primary current spikes when fired; absence or abnormal shape indicates open/short or driver failure

Diagnostic algorithm

Safety first: park on level surface, set parking brake, and follow vehicle manufacturer's safety procedures.
Read and record all codes and freeze-frame data. Note accompanying misfire codes (P0301 etc.) and engine conditions when code set.
Perform a visual inspection of the coil, connector, and wiring harness for damage, corrosion, oil intrusion, or melted insulation.
Verify battery voltage (key ON and while cranking). Low voltage can cause incorrect PCM readings; repair charging/battery issues first.
Check related fuses and ignition power relay; replace if faulty.
Backprobe the coil primary connector. With a DVOM or scope, verify battery supply at the power terminal (key ON/crank) and proper pulsed signal at the driver terminal during cranking.
Measure primary DC resistance of the coil (power off, disconnected). Compare to OEM spec. If out of range, replace coil.
If resistance is OK, use an oscilloscope to observe the primary waveform while cranking/idle. Look for proper pulsed driver, clean switching edge, and expected ring. An absent or abnormal waveform suggests open wiring or PCM driver fault.
Swap coil A with a known-good coil from another cylinder (if same coil type). If the fault follows the coil, replace the coil. If it stays with the same cylinder, suspect wiring or PCM.
Perform continuity and short-to-ground/power tests on wiring between coil connector and PCM connector. Repair damaged wiring or poor connectors.
If wiring and coil test good but problem persists, test/replace PCM only after confirming all other components and wiring are good or consult manufacturer tech data.
Clear codes and test drive to confirm repair. Recheck for return of the code and monitor for misfire symptoms.

Likely causes

Faulty ignition coil A (most common)
Intermittent/loose connector at coil (corrosion or bent pins)
Damaged wiring harness to coil (chafing, heat damage) causing open or short
Low battery or poor supply voltage under cranking
PCM/ECM driver failure (after other causes eliminated)

Fault status

⚠️ Status

PCM detected abnormal behavior in Ignition Coil A primary circuit (open, short, excessive resistance or driver fault). MIL may be set and misfire symptoms can occur. Inspect coil, connector, wiring, power supply and PCM driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5–2.5 hours

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P1352 — Ignition Coil A Primary Circuit Fault