P0352: Ignition coil B primary or secondary circuit fault

Ignition coil B circuit

Severity: Inspect soon

P0352 means the engine computer saw a fault in the circuit for ignition coil B. That coil's cylinder may misfire, which wastes fuel and can overheat the catalytic converter, and on some cars it causes hard starting, a no-start or a stall. Get it inspected soon.

It gets more serious if:

Stop: The check engine light is flashing. That means misfire bad enough to damage the catalytic converter is happening right now; Ford warns the extra exhaust heat can damage the converter and nearby parts and could cause a fire. Pull over when safe and avoid further driving, or at most drive gently and slowly to the nearest shop (EPA's own advice is to minimise driving and avoid speed and heavy loads).
Stop: The engine stalls, cuts out while driving, or cranks but will not start. Ford lists a no-start for coil circuit codes caused by a poor engine ground, and owners report stalls in traffic with coil codes stored; Toyota recalled a crank sensor fault that could stall the engine because a stall at speed may increase the risk of a crash. Do not keep driving; have it towed or checked where it sits.

Source: how we rate severity

P0352 in short

P0352 means the engine computer detected a problem in the circuit for ignition coil B, which fires one cylinder. Check the coil, its connector, the engine grounds and the spark plug well first, then test the wiring. Expect a misfire on that cylinder. Get it inspected soon, and stop driving if the light flashes.

Each ignition coil turns battery voltage into the high voltage that fires a spark plug. The engine computer switches coil B on and off and watches the circuit; P0352 sets when what it commands and what it sees do not match.

Which cylinder coil B serves depends on the engine, so check the service information. GM's service information notes that high resistance in the circuit can cause a misfire without setting the code, so a misfire code on the same cylinder points the same way.

Worn plugs, oil or water in the plug well and loose engine grounds are common reasons for coil circuit faults. Fix those too, or a new coil may fail again or the code may return.

Most likely causes

Cause 1: Failed ignition coil B
Common general cause
Why it ranks here
Coils break down from heat, vibration and moisture, and an open or shorted winding is the most direct way to set a coil circuit code. GM's test path ends with replacing the coil once wiring checks pass.
What would change this
Rises if the coil is cracked, carbon-tracked or oil-soaked, or the fault follows the coil when swapped to another cylinder; falls if the code stays with the cylinder.
How to test the ignition coil
Cause 2: Coil supply, ground or control wiring or connector fault
Common general cause
Why it ranks here
The coil needs battery voltage, a good ground and a control signal from the engine computer. A loose connector or damaged wire looks the same to the computer as a failed coil.
What would change this
Rises if supply voltage is missing with the ignition on, or the ground or low-reference circuit reads high resistance (GM's limit is under 5 ohms).
How to test the ignition coil
Cause 3: Worn spark plug or oil/water in the plug well damaging the coil
Common general cause
Why it ranks here
A worn plug raises the voltage the coil must produce, and oil or water in the plug well breaks down coil insulation. These are why coils fail, and a new coil fails again if they are ignored.
What would change this
Rises with an overdue plug change, a worn plug gap, or oil or water found in the plug well.
How to test the spark plug
Cause 4: Poor engine ground connection (2017 Escape 1.5L)
Supported by vehicle data
Why it ranks here
Ford tells technicians to check two engine grounds near the coils and turbo before other repairs when P0351-P0354 set with misfire or a no-start on the 2017 Escape 1.5L EcoBoost.
What would change this
Applies to the listed vehicle; rises if either ground is loose, corroded or not at the specified torque.
Cause 5: Engine computer software (some models)
Supported by vehicle data
Why it ranks here
Toyota (2007 Camry) and Ford (2021 Mustang 5.0L built on or before 11 Feb 2021) both address P0351-P0354 with an engine computer update.
What would change this
Rises if a bulletin covers your vehicle and the update has not been done.
How to test the engine control module (ecm / pcm)
Cause 6: Damaged crank trigger causing coil faults (2015-2016 Fiesta 1.6L)
Supported by vehicle data
Why it ranks here
Ford found that a damaged or warped Hall-effect window on the flywheel could set P0351/P0352 with rough running or a no-start on 2015-2016 Fiesta 1.6L engines.
What would change this
Applies only to the listed vehicles; rises if the coil control signal is inconsistent during Ford's pinpoint test.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: With the engine off, find which coil is B in the service information, then inspect it and its connector: look for cracks, carbon tracks, a loose or corroded connector, and oil or water in the plug well.
Low riskTool: flashlight, service information for which coil is B
- IfOil or water in the well, or a worn plug
  It meansFix the leak and plug as well as the coil.
  Points to: Worn spark plug or oil/water in the plug well damaging the coil
- IfCracked, burned or tracked coil
  It meansThe coil is damaged.
  Points to: Failed ignition coil B
- IfEverything looks good
  It meansCheck the grounds and supply.
  Go to step 2
Step 2: With the engine off, check that the engine and cylinder head ground straps near the coils are clean and tight, and look up any bulletin for your vehicle.
Low riskTool: hand tools, service information
- IfA ground is loose or corroded
  It meansClean and tighten it to specification, clear the code and retest.
  Points to: Poor engine ground connection (2017 Escape 1.5L)
- IfGrounds are good
  It meansCheck the coil supply.
  Go to step 3
Step 3: Unplug the coil and, with the ignition on and the engine off, check for supply voltage at the harness connector.
Use cautionTool: digital multimeter or test lamp, wiring diagram
Warning:Keep the engine off. Do not crank the engine with a coil unplugged or probe the coil while the engine runs; ignition voltage can cause a serious shock.
- IfSupply is low or missing
  It meansA wiring, fuse or relay problem.
  Points to: Coil supply, ground or control wiring or connector fault
- IfSupply is normal
  It meansCheck the coil itself.
  Go to step 4
Step 4: With the engine off, swap coil B with a coil from another cylinder (where they are interchangeable), clear the code and see whether the fault moves.
Use cautionTool: hand tools, scan tool
Warning:Only swap coils with the engine off and cool. Keep clear of moving parts when restarting.
- IfThe code moves to the other coil's letter
  It meansThe coil has failed.
  Points to: Failed ignition coil B
- IfThe code stays on coil B
  It meansThe fault is in the wiring, computer or software.
  Go to step 5
Step 5: Have a shop check the coil control and low-reference circuits from the engine computer, and look for bulletins or software updates for your vehicle.
Best left to a shopTool: scan tool with output controls, lab scope, service information
Warning:Checks with the engine running involve high ignition voltage and moving parts. Leave this to a shop.
- IfControl or low-reference wire open, shorted or high resistance
  It meansRepair the wiring.
  Points to: Coil supply, ground or control wiring or connector fault
- IfA bulletin or update covers the code
  It meansFollow the bulletin.
  Points to: Engine computer software (some models)
- IfInconsistent control signal on a listed Fiesta
  It meansFord's bulletin points to the flywheel trigger.
  Points to: Damaged crank trigger causing coil faults (2015-2016 Fiesta 1.6L)

Symptoms

Rough running or misfire
Reduced power
Hard starting or no start Gets more serious: stop and have it checked.
Engine stalls while driving Gets more serious: stop and have it checked.
Check engine light flashing Gets more serious: stop and have it checked.

Compare with: Rough idle with the check engine light on, Car shaking with the check engine light on

How to fix

Step 1: Write down every stored code and the freeze-frame data before clearing anything, so you can tell whether the code comes back.
Step 2: If the plugs are due by the maintenance schedule, have them replaced along with any failed coil.
Warning:Only remove coils and plugs with the engine off and cool, and tighten plugs to the specified torque.

Parts and cost context

Ignition coil:Confirm the coil is at fault (it fails a test or the code follows it) before buying one; on many engines the coils are the same part for every cylinder.
Spark plug:Replace the plug on the same cylinder if it is worn or due; a worn plug shortens the new coil's life.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

2015–2016 · Fiesta · 1.6L Ti-VCT
Supported by vehicle data
On the 1.6L Ti-VCT, Ford links P0351/P0352 with rough running or a no-start to a damaged flywheel trigger window. Ask a dealer to check SSM 45988 before replacing coils.
2006–2008 · Fusion
Supported by vehicle data
Ford has a bulletin for coil circuit codes with damaged coil-on-plug units on this model. Ask a dealer to check TSB 13-4-17.
2007–2008 · Edge
Supported by vehicle data
Ford has a bulletin for coil circuit codes with damaged coil-on-plug units on this model. Ask a dealer to check TSB 13-4-17.
2008 · Taurus
Supported by vehicle data
Ford has a bulletin for coil circuit codes with damaged coil-on-plug units on this model. Ask a dealer to check TSB 13-4-17.
2017 · Escape · 1.5L EcoBoost
Supported by vehicle data
On the 1.5L EcoBoost, Ford links coil circuit codes with misfire or a no-start to loose engine grounds near the coils and turbo. Ask a shop to check SSM 47180 before replacing coils.
2021 · Mustang · 5.0L
Supported by vehicle data
On 5.0L cars built on or before 11 Feb 2021, Ford fixes intermittent rough running with coil circuit codes by reprogramming the PCM (TSB 21-2174).
2021–2024 · Bronco · 2.3L EcoBoost
Supported by vehicle data
On the 2.3L EcoBoost, Ford says coil codes may set against the wrong cylinder. Make sure the shop finds the actual cylinder with a power balance test before replacing a coil (SSM 52342).

SSM 45988Status unverified
Ford SSM 45988: P0351/P0352 with rough running, hard or no start
2015–2016fiesta · 1.6L Ti-VCT · issued August 11, 2016 · NHTSA 10092410
On 2015-2016 Fiesta with the 1.6L Ti-VCT engine, if the test light flash is inconsistent or dim during the coil pinpoint test, suspect a damaged or warped Hall-effect window on the flywheel and replace the flywheel.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
TSB 13-4-17Status unverified
Ford TSB 13-4-17: P0351-P0355 with coil-on-plug damage
2006–2008fusion, edge, taurus · issued April 24, 2013 · NHTSA 10052190
Covers ignition coil circuit codes with one or more damaged coil-on-plug units on 2006-2008 Fusion, Milan, MKZ and Zephyr, 2007-2008 Edge and MKX, and 2008 Taurus and Sable. NHTSA's summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
SSM 47180Status unverified
Ford SSM 47180: misfire, no start, P0351-P0354 from poor engine grounds
2017escape · 1.5L EcoBoost · issued March 22, 2018 · NHTSA 10137104
On the 2017 Escape 1.5L EcoBoost, coil circuit codes with misfire, lack of power or a no-start can come from poor grounds G111 (on the cylinder head near coils 2 and 3) and G110 (near the turbo). Check and tighten them before other repairs.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
TSB 21-2174Status unverified
Ford TSB 21-2174: rough running with P0351-P0354
2021mustang · 5.0L · issued June 2, 2021 · NHTSA 10198584
2021 Mustang 5.0L built on or before 11 Feb 2021 may run rough intermittently with coil circuit codes because of a PCM software parameter; the PCM is reprogrammed.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
SSM 52342Status unverified
Ford SSM 52342: ignition codes may name the wrong cylinder
2021–2024bronco · 2.3L EcoBoost · issued March 7, 2024 · NHTSA 10251954
On the 2021-2024 Bronco 2.3L and 2022-2024 Bronco Raptor, P0352 and other coil codes may set against the wrong cylinder. A real ignition fault is still present; a cylinder power balance test finds the actual cylinder first.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Toyota

2007 · Camry
Supported by vehicle data
Toyota addresses P0351-P0354 on this model with improved engine computer logic. Ask a dealer whether the update applies before replacing coils.

TSB-0101-09Status unverified
Toyota TSB-0101-09: MIL with P0351-P0354, improved ECM logic
2007camry · issued April 6, 2009 · NHTSA 10030327
Ignition coil circuit codes P0351-P0354 on the 2007 Camry (NHTSA lists the Camry Hybrid) are addressed by improved engine computer logic.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All Ignition and engine position sensors codes

P0352 questions

Which cylinder is ignition coil B?

It depends on the engine, so confirm it in the service information before replacing anything. On some Ford Bronco 2.3L engines Ford says the code can even name the wrong cylinder, so a cylinder balance test comes first.

Can I drive with a flashing check engine light?

Not if you can avoid it. A flashing light means misfire severe enough to overheat the catalytic converter is happening now. EPA advises keeping driving to a minimum. Drive gently to the nearest shop at most, or have it towed.

Should I replace the spark plug with the coil?

If the plug is worn or due for replacement, yes. A worn plug makes the coil work harder, and both DENSO and Delphi name worn plugs as a cause of coil failure.

Sources and review

How to service ignition coils — Delphi Technologies Aftermarket
What You Should Know About Catalytic Converters — AA1Car.com (Larry Carley, automotive technical writer)
Ford SSM 45988: P0351/P0352 with rough running, hard or no start, 2015-2016 Fiesta 1.6L — Ford Motor Company (via NHTSA) , August 11, 2016
Cal. Code Regs. tit. 13, § 1968.2 - Malfunction and Diagnostic System Requirements (OBD II) — California Air Resources Board (via Cornell LII)
2001 Lincoln Continental Owner's Guide - Warning lights (Check engine) — Ford Motor Company
Do you drive a 1996 or newer car or light truck? (On-Board Diagnostics, EPA420-F-02-016) — U.S. Environmental Protection Agency
Safety Recall H0H Remedy Notice: Certain 2016-2017 Model Year Tacoma Crankshaft Position Sensor, Frequently Asked Questions — Toyota Motor North America , July 24, 2017
Toyota Recalls Tacoma Pickups for Stalling — Automotive Fleet , June 9, 2017
Ford SSM 47180: 2017 Escape 1.5L misfire, no start, P0351-P0354 — Ford Motor Company / NHTSA , March 22, 2018
NHTSA complaint ODI 10494379: 2005 Ford Escape, P0351-P0354 with a stall at 45 mph — NHTSA Office of Defects Investigation (complaint flat file) , January 22, 2013
Causes of ignition coil failure — DENSO Aftermarket Europe , January 16, 2024
2011 Saab 9-4X V6 (GM): DTC P0351-P0356 — General Motors / Saab Automobile (read via saabwisonline.com)
ASE L1 Advanced Engine Performance Specialist Test: Composite Vehicle Type 4 Reference Booklet — National Institute for Automotive Service Excellence (ASE)
Ford TSB 13-4-17: P0351-P0355 with coil-on-plug damage — Ford Motor Company (via NHTSA) , April 24, 2013
Toyota TSB-0101-09: MIL with P0351-P0354 - improved ECM logic — Toyota Motor Sales (via NHTSA) , April 6, 2009
Ford TSB 21-2174: 2021 Mustang 5.0L rough running, P0351-P0354 — Ford Motor Company / NHTSA , June 2, 2021
How To Diagnose & Repair Engine Misfires — AA1Car.com (Larry Carley, automotive technical writer)
Ford SSM 52342: Bronco 2.3L ignition DTCs set against the wrong cylinder — Ford Motor Company / NHTSA , March 7, 2024

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Failed ignition coil B

Cause 2: Coil supply, ground or control wiring or connector fault

Cause 3: Worn spark plug or oil/water in the plug well damaging the coil

Cause 4: Poor engine ground connection (2017 Escape 1.5L)

Cause 5: Engine computer software (some models)

Cause 6: Damaged crank trigger causing coil faults (2015-2016 Fiesta 1.6L)

What to test first

Step 1: With the engine off, find which coil is B in the service information, then inspect it and its connector: look for cracks, carbon tracks, a loose or corroded connector, and oil or water in the plug well.

Step 2: With the engine off, check that the engine and cylinder head ground straps near the coils are clean and tight, and look up any bulletin for your vehicle.

Step 3: Unplug the coil and, with the ignition on and the engine off, check for supply voltage at the harness connector.

Step 4: With the engine off, swap coil B with a coil from another cylinder (where they are interchangeable), clear the code and see whether the fault moves.

Step 5: Have a shop check the coil control and low-reference circuits from the engine computer, and look for bulletins or software updates for your vehicle.