P0352 Code: Ignition Coil B Primary/Secondary Circuit
Coil B, normally on cylinder 2, has a circuit fault. Where cylinder 2 sits depends on the engine maker.
At a glance
Severity: Moderate
- Meaning
- Ignition Coil B Primary/Secondary Circuit
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $50–$1,500
- DIY difficulty
- Moderate
P0352 is logged when the engine computer's check of the second coil output fails: the driver switched on, but the expected current or the igniter's feedback pulse never showed up. The code points at the coil, its connector or the wires between it and the computer, and leaves fuel and compression out of it. The catch with coil B is finding it. Makers that alternate cylinders between the banks, such as GM and Toyota, put cylinder 2 at the front of the second bank, while Ford and Honda put it right next to cylinder 1 on the same bank. On four-cylinder waste-spark packs the B output usually fires cylinders 2 and 3 as a pair, and on three-coil GM V6 packs cylinders 2 and 5 share a coil.
Can I keep driving? The engine will run, but roughly and with one cylinder dead, so limit driving to getting it fixed. Stop if the check-engine light begins to flash, since that means unburned fuel is reaching the catalytic converter.
How to read P0352
- P Powertrain
- 0 Generic (SAE)
- 3 Ignition / misfire
- 52 Specific fault
Symptoms
- Steady miss at idle that smooths out a little at higher rpm
- Check-engine light with P0302, or with P0302 and P0303 on waste-spark engines
- Hesitation when pulling away or climbing a grade
- Noticeably worse gas mileage
- Engine runs fine cold and misses once warm, if the coil's insulation is breaking down
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Coil B itself has failed, either the winding or the built-in igniter
- Loose, spread or corroded terminals in the coil B connector
- Waste-spark coil tower for cylinders 2 and 3 (or 2 and 5 on GM V6 packs) has failed
- Trigger wire from the computer to coil B open or shorted to ground where the harness crosses a bracket or valve cover edge
- Bank feed or ground shared by the coils on cylinder 2's side has a high-resistance joint
- Coil driver inside the engine computer has failed
- Plug with an eroded, oversized gap overloading the coil until it broke down
Diagnosis step by step
Find cylinder 2 using your maker's numbering
On GM and Toyota V engines cylinder 2 is the front cylinder of the second bank, which on a GM V8 truck is the front passenger side and on most transverse Toyota and GM V6s is the front bank nearest the radiator. Ford and Honda number one bank first, so cylinder 2 sits beside cylinder 1: second from the front on the passenger side of a Ford V8, the middle of the rear bank on a transverse Ford or Honda V6.
Tools: Flashlight
Read the other stored codes
If coils on the same bank as cylinder 2 have also logged circuit codes, look for a bank feed or ground problem instead of several bad coils. A misfire on cylinders 2 and 3 together on a four-cylinder with a single coil pack means the pack's second circuit.
Tools: OBD-II scanner
Check the trigger signal with an LED test light
Back-probe the trigger wire at the coil B connector with an LED test light or logic probe and crank the engine. Compare the flicker with the same wire at coil 1. A trigger that arrives at a coil that has feed and ground but doesn't fire condemns the coil. No trigger points to the wire or the computer.
Tools: Multimeter, Screwdriver
Test the trigger wire end to end
With the ignition off, unplug the computer connector and the coil connector. From the computer pin to the coil pin you want well under 1 ohm, and from that wire to engine ground an open reading. Flex the harness at every bracket while you watch the meter, since a chafed wire often only fails when moved.
Tools: Multimeter
Do a terminal drag test
Push a matching male terminal into each socket of the coil B connector. It should slide in with light, even drag. A terminal that feels loose, or shows green corrosion, needs re-pinning or a new pigtail, because a new coil on a bad terminal will set the same code.
Tools: Pliers, Flashlight
Confirm the repair with live data
After the repair, watch the cylinder 2 misfire counter on the scan tool at idle and on a drive that includes light load. It should stay at or very near zero, and the code should not return after several drive cycles.
Tools: OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace coil B | Yes | $80–$260 |
| Re-pin or replace the coil B connector pigtail | No | $50–$180 |
| Repair chafed trigger wire in the engine harness | No | $100–$300 |
| Replace waste-spark coil pack (2/3 or 2/5 tower) | Yes | $120–$350 |
| Replace engine computer (rarely needed) | No | $600–$1,500 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Field data
| Ford | 4 | Edge, Escape Hybrid, Fusion Energi | |
|---|---|---|---|
| Dodge | 2 | Dart |
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
With P0352 stored the check-engine light is on, which is an automatic fail in states that run an OBD-II emissions test. Some stations also reject the car if too many readiness monitors are incomplete after a battery disconnect or code clear, so drive it for a few days first.
Frequently asked questions
Where is cylinder 2 on a V6 or V8?
It depends on the maker. GM, Toyota and Chrysler alternate cylinders between banks, so cylinder 2 is the front cylinder on the second bank. Ford and Honda count one bank first, which puts cylinder 2 right behind cylinder 1 on the same side.
The cylinder 2 coil was replaced and P0352 is still there. Why?
Either the wrong coil was changed because the numbering was misread, or the fault is in the connector or wire rather than the coil. A trigger-signal check at the coil B connector answers that in a few minutes.
My engine has a single coil pack. How can it have a coil B fault?
A waste-spark pack contains two or three separate coils in one housing, each with its own driver. On many four-cylinder engines the B circuit fires cylinders 2 and 3, and on three-coil GM V6 packs cylinders 2 and 5 share a coil. The whole pack is replaced as one part.
Can a shorted coil B damage the computer?
It can. A shorted primary winding pulls far more current through the driver than it is built for, and repeated overloading can burn that driver out. That is one reason not to leave a coil circuit code unrepaired for months.