P0352: Ignition Coil B Primary/Secondary Circuit
Key takeaways
- P0352 is an electrical code: the engine computer saw a bad signal in the circuit that fires ignition coil B, usually the coil for cylinder 2.
- Drive only short, gentle trips; if the check engine light starts flashing or the engine shakes hard, stop.
- Check the coil connector, wiring and grounds first ($100–$250) before buying a coil ($120–$300).
- 15 complaints filed with NHTSA mention P0352, and 4 of them are Ford Escapes, 3 of those 2005 models.
- Ford bulletins for P0352 point to engine computer software, bad engine grounds and a flywheel sensor problem, not only coils.
What P0352 means
The engine computer found an electrical problem in the circuit that fires ignition coil B. Scanners call it Ignition Coil B Primary/Secondary Circuit. The computer switches each coil on and off to make the spark, and on many engines the coil sends a confirmation signal back. When the current, voltage or feedback on coil B’s circuit isn’t what the computer expects, it sets P0352.
On most engines with one coil per spark plug, coil B is the coil for cylinder 2. On older engines where one coil fires two plugs, coil B serves a pair of cylinders. Your service information shows which.
This is a circuit code, not a misfire count. The coil itself, its connector, its wiring, its power and ground, or the computer that drives it can all set it.
Is it safe to drive?
Short trips only, and stop if the light starts flashing. When coil B drops out, its cylinder usually misfires, and you feel a shake at idle or a stumble under load. With a steady light and mild roughness, drive gently to a shop and avoid towing or hard acceleration. A flashing check engine light means the misfire is heavy enough to overheat the catalytic converter; pull over and have the car towed. The same goes for a stall or a no-start.
Causes, ranked
| Cause | How you confirm it | Typical cost (US independent shop, 2026) |
|---|---|---|
| Loose, corroded or wet coil connector, or chafed wiring | Look at coil B’s plug for green corrosion, water or a broken lock tab; wiggle the harness with the engine running | $100–$250 |
| Failed ignition coil B | Swap coil B with a neighbor; the code changes to that coil’s number (P0351, P0353) | $120–$300 for one coil |
| Poor engine ground or coil power feed | Voltage-drop test on grounds and the coil supply; often several P035X codes at once | $100–$250 |
| Software fault | Shop finds a matching bulletin for your engine | $100–$200; often $0 under a bulletin |
| Engine computer coil driver failed | Wiring and coil test good, but the computer’s output for coil B is dead | $800–$1,800 plus programming |
What to check first
- Read all the codes. P0352 alone points to coil B’s own circuit. P0351 through P0354 together point to a shared power feed, fuse or ground.
- Inspect coil B’s connector. Unplug it, look for water, corrosion or pushed-back pins, and make sure it locks.
- Swap the coil with a neighbor, clear the code and drive. If the code follows the coil, replace the coil.
- Check power and ground at the coil with a meter or test light, including the engine-to-body ground straps.
- Suspect the computer last, only after the wiring checks out end to end.
The bulletins lean toward Ford. Ford has an engine-computer reprogram for the 2021 Mustang 5.0, a fix for poor ground connections near coils 2 and 3 on the 2017 Escape 1.5L EcoBoost, and a damaged flywheel sensor window on the 2015–2016 Fiesta 1.6L. Ford also notes that on some 2021–2024 Broncos and 2023–2025 gas Super Duty, E-Series and medium-duty trucks, the engine computer can log the coil code against the wrong cylinder, so the shop should check the bulletin before pulling coil B.
The NHTSA complaints are thin: 15 in total, 4 of them Ford Escapes, 3 of those from the 2005 model year. Those are owner reports, not a confirmed cause.
What it costs
The cheap outcome is a connector, ground or wiring repair, $100–$250. The common outcome is one ignition coil, $120–$300. The expensive outcome is an engine computer, $800–$1,800 plus programming, which is rare and should only follow a full circuit test. An hour of diagnosis, usually $100–$180, is cheaper than buying a coil for a corroded plug. If you want to talk through your codes first, ask our AI mechanic.
Related codes
P0352 often comes with P0302, the cylinder 2 misfire it causes, or with P0300. If P0351, P0353 and P0354 are also set, look at the shared power and ground first. For what a steady light means in general, see check engine light on and can I drive with the check engine light on.
What owners report to NHTSA
15 complaints filed with NHTSA mention P0352, 9 of them since 2015, across 10 different models. The component owners most often filed it under: electrical system.
Most-reported models
| Vehicle | Complaints | Model years reported |
|---|---|---|
| FORD ESCAPE | 4 | 2005, 2006 |
Manufacturer service bulletins that name P0352
11 technical service bulletins and manufacturer communications filed with NHTSA mention P0352, from 6 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- FORD F-450 SD (2023, 2024, 2025), bulletin 10254127: Some 2023-2024 F-Super Duty/F-53 Motorhome/F-59 Commercial Stripped Chassis or 2023-2025 E-Series/F-650/F-750 vehicles equipped with a gas engine may exhibit an illuminated MIL with ignition system DTC(s) P0352, P0353, P…
- FORD BRONCO (2021, 2022, 2023, 2024), bulletin 10251954: Some 2022-2024 Broncos Raptors built on and before 13-Feb-2024 and 2021-2024 Broncos equipped with a 2.3L EcoBoost engine may exhibit an illuminated MIL with ignition system DTC(s) P0352, P0353, P0354, P0355, P0357, P230…
- FORD MUSTANG (2021), bulletin 10198584: Some 2021 Mustang vehicles equipped with a 5.0L engine and built on or before 11-Feb-2021 may exhibit an intermittent rough running drivability concern with an illuminated malfunction indicator lamp (MIL) and diagnostic …
- FORD ESCAPE (2017), bulletin 10137104: Some 2017 Escape vehicles equipped with a 1.5L EcoBoost engine may exhibit a misfire, lack of power, no start and/or illuminated MIL with diagnostic trouble codes (DTCs) P0351, P0352, P0353 and/or P0354 stored in the pow…
- FORD FIESTA (2015, 2016), bulletin 10092410: SOME 2015-2016 FIESTA WITH 1.6L TIVCT ENGINE MAY HAVE A CHECK ENGINE LIGHT WITH DTC'S P0351 AND/OR P0352 WITH POSSIBLE RUNS ROUGH, HARD OR NO START. FOLLOW PPT JE FOR NORMAL DIAGNOSTICS. IF LIGHT FLASH IS INCONSISTENT OR…
- BUICK ENCLAVE (2009), bulletin 10113025: This Preliminary Information communication provides information to the technician about vehicles that have a Service Engine Soon Malfunction Indicator Lamp on. Technician will find Diagnostic Trouble Codes P0300, P0301, …
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.
Frequently asked questions
Is P0352 the same as a cylinder 2 misfire?
Not quite. P0352 means the computer found an electrical fault in coil B's circuit. That usually causes a misfire on the cylinder the coil fires, so P0302 often shows up with it, but P0352 tells you to look at the coil circuit first.
Can I drive with P0352?
Short, gentle trips to a shop are usually fine if the light is steady and the engine runs reasonably smoothly. A flashing check engine light or heavy shaking means a strong misfire, so stop and have it towed.
Will a new coil fix P0352?
Only if the coil is the problem. Swap coil B with a neighbor first. If the code changes to that neighbor's code, such as P0351 or P0353, the coil is bad. If P0352 stays, the fault is in the wiring, connector, ground or computer.
Which coil is coil B?
On most engines with one coil per spark plug, coil B fires cylinder 2. On older engines where one coil fires two plugs, coil B serves a pair of cylinders. Check the service information for your engine before you pull anything.