P0350⚡ Ignition (one or more ignition coils or coil packs)Stop and fix promptly

P0350: Ignition Coil Primary/Secondary Circuit (Meaning, Causes, Fixes)

Reviewed 2026-10-25 · Based on 2 cited source(s)

What P0350 means

Most OBD-II engines have one ignition coil per cylinder sitting on or next to the spark plug; some use coil packs that fire several cylinders through longer plug leads. OBD-Codes.com explains that each coil gets switched battery voltage with the key on and fires when the powertrain computer (PCM) grounds it with a pulse. If the PCM detects that any coil circuit is not being completed when it applies that ground pulse, it stores P0350 and may turn on the check engine light. RepairPal describes the same thing in terms of the PCM's coil drivers: special transistors that switch the coils on and off, and if the PCM cannot control a coil it sets P0350. Unlike P0351 through P0362, which each name a specific coil (A, B, C and so on), P0350 does not say which coil, so OBD-Codes.com suggests using any coil-specific codes stored at the same time to find the one at fault. The sources differ in a few details. OBD-Codes.com lists misfires and misfire codes such as P0301 to P0304 as likely companions, while RepairPal's symptoms are only decreased engine performance and increased fuel consumption. OBD-Codes.com's causes also include a bad ignition system relay and blown fuses or fusible links, which RepairPal does not list. Neither source gives a repair cost.

Severity: can I keep driving?

Stop and fix promptly

Get it fixed soon and go easy on the engine until then. Both sources treat P0350 as serious: OBD-Codes.com says misfires will likely come with it, so it should be categorized as severe, and RepairPal rates it Urgent, meaning immediate action is needed. If the check engine light is flashing, the engine is misfiring badly, so stop hard driving and get it looked at.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Open or shorted coil primary or secondary circuits, including corroded, burned or rodent-chewed wiring (OBD-Codes.com); wiring issue (RepairPal)
  2. Bad ignition coil or coil pack (OBD-Codes.com, RepairPal)
  3. Bad ignition system relay (OBD-Codes.com only)
  4. Blown fuses or fusible links (OBD-Codes.com only)
  5. Faulty engine computer (PCM) or a PCM programming error (OBD-Codes.com, RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Start with a visual check of every coil or coil pack connector and its wiring. OBD-Codes.com says to look for broken connectors and burned, broken or corroded wires, notes that coil connector ends are known to corrode over time, and says rodent-damaged wiring has caused P0350 on several cars it has seen.
  2. Read all stored codes and freeze frame data with a scan tool and write them down. Coil-specific codes (P0351 to P0362) or misfire codes for a particular cylinder point you to the coil or circuit at fault. Then clear the codes and test drive to see if P0350 comes back.
  3. Check for technical service bulletins (TSBs) for your vehicle that match the code and symptoms.
  4. If no coil-specific codes point the way, find the weak coil. OBD-Codes.com describes unplugging one coil connector at a time while the engine is misfiring and watching for the one that makes no change in engine speed. Unplug the low-voltage connector rather than pulling plug boots or wires off a running engine: the spark can exceed 50,000 volts, and the source warns to keep high-voltage testing away from flammable liquids. Clear codes afterward.
  5. At the suspect coil, with the key on, use a multimeter to check for battery voltage at the connector. If it's missing, trace the supply circuit for blown fuses or a bad relay, remembering that a blown fuse is caused by a short somewhere. With the computer and other modules unplugged, check the circuits for continuity and resistance against your service manual's specs and repair any open or short.
  6. If power is present, check the connector for a ground pulse from the computer while cranking or running. OBD-Codes.com says to suspect a bad driver in the computer only if that pulse is missing and there are no other ignition codes, including crankshaft or camshaft position sensor codes.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The check engine light is flashing or the engine misfires badly
  • You can't tell which coil is at fault and don't have a multimeter or wiring diagram
  • Fuses keep blowing in the coil supply circuit
  • The code returns after a new coil
  • Tests point to the engine computer, which may need programming to your vehicle

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0350?

Only gently and for a short time. OBD-Codes.com calls it severe because misfires usually come with it, and RepairPal rates it Urgent. Get it diagnosed soon, and stop hard driving if the check engine light flashes.

What's the difference between P0350 and P0351?

P0350 is a general coil circuit fault that doesn't name a coil. P0351 through P0362 each point to a specific coil (A, B, C and so on). If one of those is stored with P0350, start with that coil and its wiring.

Will a tune-up fix P0350?

No. OBD-Codes.com says a maintenance tune-up is not a fix for P0350. The cause is usually wiring, a connector, a coil or coil pack, a fuse or relay, or the computer.

How much does it cost to fix P0350?

Neither source gives a repair cost for P0350. It can be anything from a corroded connector to a coil or a wiring repair, so find the faulty circuit before buying parts.

Sources

  1. OBD-Codes.com: P0350 Ignition Coil Primary/Secondary Circuit Malfunction (rated severe)
  2. RepairPal: P0350 Ignition Coil Primary/Secondary Circuit (rated Urgent)

Last reviewed 2026-10-25. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.