P0352 on 2021-2024 Ford Bronco: Ignition Coil 'B' Circuit Causes and Fixes

What's Unique About the 2021-2024 Ford BRONCO

For the 2021-2024 Bronco with the 2.3L or 3.0L EcoBoost engine, this code has a significant platform-specific issue. Ford has issued Technical Service Bulletins (TSBs) stating the PCM software can have 'incorrect cylinder to DTC mapping'. This means that while a real ignition fault exists, the P0352 code for cylinder #2 might be triggered when the actual problem is on a different cylinder. This makes standard diagnosis tricky and can lead to replacing the wrong parts. The TSB explicitly states that even with the mapping error, a real ignition system concern is present and requires diagnosis.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light illuminated or flashing
• Rough engine idle
• Engine hesitation or stumbling during acceleration
• Noticeable loss of engine power
• Engine misfiring, which may feel like a shudder or vibration
• Difficulty starting the engine.

Most Likely Causes

1. PCM Software Error (Incorrect Cylinder Mapping) 🔴 High Probability Ford TSBs 24-2406 and SSM 52342 directly address this issue on 2021-2024 Broncos with 2.3L and 3.0L EcoBoost engines.
   How to confirm: A Ford dealer or a qualified shop must use the Ford Diagnostic & Repair System (FDRS) to run a power balance test. This test graphically shows the contribution of each cylinder, 🎬 Watch: How to perform a Ford power balance test. allowing the technician to identify the actual source of the misfire, even if the DTC points elsewhere. The TSB notes that because the PCM cuts fuel to the cylinder it *thinks* is bad, a power balance test may show two cylinders dropping out. The one to diagnose is the one that is dropping out *without* an associated ignition DTC.
   Typical fix: Reprogram the Powertrain Control Module (PCM) to the latest software version. This corrects the mapping issue. The underlying hardware cause (like a bad coil) must still be fixed on the correct cylinder identified by the power balance test.
   Est. part cost: $0 (if under warranty) - $150
2. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil Ignition coils are a common failure point on many modern engines due to high heat and electrical stress. They are responsible for converting low battery voltage to the high voltage needed for spark.
   How to confirm: After identifying the correct cylinder via a power balance test, swap the suspect ignition coil with one from a known good cylinder. Clear the codes and drive. 🎬 See these troubleshooting tips for EcoBoost misfire codes. If the misfire code moves to the new cylinder (e.g., P0353 if you moved it to cylinder 3), the coil is bad.
   Typical fix: Replace the failed ignition coil. It is held on by a single 8mm bolt.
   Est. part cost: $40-$80
3. Worn or Faulty Spark Plug 🟡 Medium Probability → Shop Spark Plug EcoBoost engines can be hard on spark plugs due to turbocharging and direct injection. A worn electrode, carbon fouling, or a cracked ceramic insulator can cause a misfire and trigger an ignition coil circuit code.
   How to confirm: After confirming the coil is good, remove the spark plug from the misfiring cylinder. Inspect it for excessive wear, carbon fouling, oil, or cracks in the ceramic insulator. Compare it to a new plug.
   Typical fix: Replace the faulty spark plug. It is recommended to replace all spark plugs as a set if they are near the end of their service life (typically 60,000-100,000 miles, but check owner's manual).
   Est. part cost: $15-$30 per plug
4. Damaged Wiring or Loose Connector ⚪ Low Probability Vibrations and engine bay heat can sometimes lead to wiring issues. The plastic locking tabs on connectors can become brittle and break.
   How to confirm: Visually inspect the wiring harness and connector going to the ignition coil on the affected cylinder. Check for any signs of melting, chafing, or corrosion on the pins. Use a multimeter to check for continuity and proper voltage at the connector with the key on.
   Typical fix: Repair the damaged section of the wire or replace the ignition coil pigtail connector.
   Est. part cost: $15-$40 for a connector

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) This is very rare. The coil driver circuit inside the PCM can fail, but all other possibilities should be exhausted before condemning the PCM. The software glitch mentioned in the TSB is a programming issue, not a hardware failure. In some other Ford models, a failed coil has been known to send a voltage spike back and damage the PCM, but this is less common.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0352 and check for any other codes.
2. Crucial Step for Bronco: Be aware of TSB 24-2406 and SSM 52342. The code is likely pointing to the wrong cylinder.
3. Professional Diagnosis: Have a Ford dealer or qualified shop perform a power balance test using FDRS to identify the actual failing cylinder. This is the most reliable method.
4. DIY Diagnosis (with caution): If you cannot perform a power balance test, you can try swapping the ignition coil from cylinder #2 with another cylinder (e.g., #3). Clear the codes and drive. If the code changes to P0353, you have found the bad coil. If the code remains P0352, the fault is likely not on cylinder #2, and the PCM mapping is incorrect. You may have to repeat the swap process on other cylinders until the code follows the coil.
5. Once the correct cylinder is identified, inspect the ignition coil connector and wiring for damage, corrosion, or loose pins.
6. If the coil swap doesn't isolate the issue, swap the spark plug from the suspect cylinder with another. If the misfire follows the plug, the plug is bad.
7. If all parts test good, the issue may be the wiring between the coil and the PCM, or in rare cases, the PCM itself.
8. Essential Final Step: Regardless of the hardware fix, it is highly recommended to have a Ford dealer perform the PCM software update outlined in TSB 24-2406 to prevent future misdiagnosis.

Parts You'll Likely Need

• Ignition Coil (OEM #JX6Z-12029-B (replaces JX6Z-12029-A)) — This is the most common hardware failure for ignition circuit faults. This part is also listed under the ID DG576.
  Trusted brands: Motorcraft, Standard Motor Products, NGK
  OEM price range: $60-$90
  Aftermarket price range: $40-$70
• Spark Plugs (OEM #Motorcraft SP-578 (2.3L) or Motorcraft SP-594 (3.0L)) — A worn or fouled spark plug can cause a misfire that the PCM may interpret as a coil circuit fault. Part number SP-578 is specified for the 2.3L Bronco. 🎬 Watch: Step-by-step spark plug installation on a 2.3L Bronco.
  Trusted brands: Motorcraft, NGK, Bosch
  OEM price range: $20-$30
  Aftermarket price range: $15-$25
• Ignition Coil Connector (OEM #WPT-1492) — If the connector's locking tab is broken or the terminals are corroded, it will need to be replaced to ensure a solid connection.
  Trusted brands: Motorcraft, Dorman
  OEM price range: $30-$50
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0300 — Random Misfire Detected. This can appear if the misfire is intermittent or if the PCM is struggling to isolate the specific cylinder.
• P030X (e.g., P0301, P0303, P0304) — Cylinder-specific misfire code. You might see a misfire code that does not match the P0352 cylinder number (e.g., P0352 and P0304 together), which is a strong clue for the PCM mapping issue.
• P0351, P0353, P0354, P0355, P2303, P2306 — These are other ignition coil primary/secondary circuit codes for other cylinders. The TSBs list these as other potential codes that can be set incorrectly due to the same software glitch.

Technical Service Bulletins (TSBs) & Recalls

• TSB 24-2406: States that some 2021-2024 Broncos with 2.3L/3.0L engines may exhibit ignition system DTCs (like P0352) for the incorrect cylinder due to a PCM software mapping error. Recommends a power balance test for diagnosis and a PCM reprogram to fix the mapping.
• SSM 52342: An earlier version of the bulletin above, also describing the incorrect cylinder mapping issue for vehicles built on or before 13-Feb-2024.

Platform-Specific Known Issues

• A Powertrain Control Module (PCM) software error can cause the vehicle to report an ignition fault for the wrong cylinder. For example, the fault may be on cylinder 3, but the code stored is P0352 (for cylinder 2). This is documented in Ford TSB 24-2406.
• The diagnostic procedure in the TSB is specific: use a power balance test to find the true failing cylinder. The PCM will cut fuel to the cylinder it *thinks* is bad, so the cylinder that needs diagnosis is the one showing a power drop *without* a corresponding DTC.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Resistance — expected: 0.5 - 1.5 Ohms. Failure: A reading outside this range (especially an open circuit or 'OL') indicates a faulty coil.
• Ignition Coil Connector Voltage (Key On, Engine Off) — expected: Pin 3 (Power): Battery Voltage (~12.6V). Pin 4 (Ground): Near 0V.. Failure: Low or no voltage on the power pin points to a fuse or wiring issue. High resistance on the ground pin indicates a bad ground connection.

Hidden / Shadow Codes Worth Checking

• Mode $06, Test IDs $A2-$A5: These are not DTCs but onboard test results for misfire counts on a 4-cylinder engine. Test ID $A2 corresponds to Cylinder 1, $A3 to Cylinder 2, $A4 to Cylinder 3, and $A5 to Cylinder 4. A high count on a specific cylinder's Test ID points to the true source of a misfire. (see via Use an advanced OBD-II scanner that supports Mode $06 data. This is invaluable for confirming the TSB's cylinder mapping error; for example, if P0352 is present but Test ID $A4 shows high misfire counts, the actual fault is on cylinder #3.)

Scan Tool Commands That Help

• Ford IDS / FDRS: Power Balance Test — This is the definitive test for this P0352 issue on a Bronco. It graphically displays the RPM contribution of each cylinder. When a cylinder is disabled, its line on the graph will dip, showing its contribution. If you disable a cylinder and the RPM doesn't change, that cylinder wasn't contributing, indicating it's the source of the misfire. This command is essential to bypass the incorrect DTC and find the real problem cylinder.

Wiring & Ground Locations

• G104 — On the right front of the engine compartment, near the passenger side strut tower.. This is a primary engine and chassis ground point. A loose or corroded connection at G104 can cause a wide range of intermittent electrical issues, including erratic behavior of the ignition system and PCM, potentially triggering false P035x codes.
• Ignition Coil Connector (2.3L) — Directly on top of each ignition coil.. Knowing the pinout allows for precise electrical testing. For the 4-pin connector: Pin 1 is the control signal (CLS) from the PCM, Pin 2 is the monitor signal (IGND) to the PCM, Pin 3 is battery power (B+) from a fuse in the underhood fuse box, and Pin 4 is the ground. Testing for power, ground, and signal here can quickly determine if the coil, wiring, or PCM is at fault.

Real Owner Repair Stories

• Bronco6G.com forum user (2022 Ford Bronco Badlands 2.3L, ~18,000 miles) — Rough idle and check engine light with code P0352.
  ❌ Tried (didn't work) Initial dealer diagnosis suggested replacing the ignition coil on cylinder #2 based on the code.
  ✅ What actually fixed it The owner mentioned the TSB. The dealer then performed a power balance test which revealed the actual misfire was on cylinder #4. They replaced the ignition coil and spark plug on cylinder #4 and performed the PCM software update per TSB 24-2406. This resolved the issue completely.
• Forum user report (2021 Ford Bronco 2.7L EcoBoost) — Check engine light with P0353 (Cylinder 3 coil circuit).
  ❌ Tried (didn't work) Swapping the ignition coil from cylinder #3 to #1., Swapping the spark plug from cylinder #3 to #2.
  ✅ What actually fixed it The code did not follow the swapped parts. A detailed inspection of the wiring harness near the back of the engine revealed it was rubbing against a metal bracket, causing a wire to the cylinder #3 coil connector to chafe and short. Repairing the wire and securing the harness away from the bracket fixed the problem.

OEM Part Supersession History

• JX6Z-12029-A → JX6Z-12029-B — Standard revision for reliability improvements or supplier change. The 'B' revision is a direct, fully compatible replacement for the 'A' part.

Model Year Variations Within This Range

• 2021-2024 (pre-update): According to Ford's Special Service Message (SSM) 52342, Broncos built on or before February 13, 2024, are most likely to have the PCM software that causes the incorrect cylinder-to-DTC mapping. Vehicles built after this date or those that have had the TSB 24-2406 software update applied should report the correct cylinder.