Faulty ignition coil or coil driver for cylinder 4; Open or short circuit in the cylinder 4 ignition control wiring; Corroded, loose or damaged connector at the coil, ignition module or engine control module; Faulty ignition control module (on models that have a separate one); Poor power or earth supply to the coil or ignition module; Internal fault in the engine control module.

P1364

IC Cylinder 4 Not Toggling After Enable.

Buick
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
3: AreaIgnition system or misfire
64: FaultThe specific fault in that area

What it means

On Buick (GM) models, P1364 means the ignition control (IC) circuit for cylinder 4 is not toggling after the ignition control has been enabled. The engine control module commands the ignition control to switch for cylinder 4 but does not see the expected change in the circuit, so it sets the code. This points to a fault in the cylinder 4 ignition control circuit, the coil or driver, or the module itself. The exact ignition layout (coil per cylinder, coil packs or a separate ignition module) depends on the model and engine.

Symptoms

Engine misfire, especially on cylinder 4
Rough idle or shaking at idle
Hesitation or loss of power under acceleration
Hard starting or extended cranking
Check engine light on, possibly flashing under load
Poor fuel economy

Possible causes

Faulty ignition coil or coil driver for cylinder 4likely
Open or short circuit in the cylinder 4 ignition control wiringlikely
Corroded, loose or damaged connector at the coil, ignition module or engine control modulelikely
Faulty ignition control module (on models that have a separate one)possible
Poor power or earth supply to the coil or ignition modulepossible
Internal fault in the engine control modulerare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine speed, load and temperature when the code set.
Check for other ignition or misfire codes, which can show whether the fault is limited to cylinder 4 or wider.
Visually inspect the cylinder 4 coil connector, wiring and harness for chafing, heat damage, corrosion or water ingress.
Check the coil and ignition module power and earth supplies against the manufacturer's wiring diagram for your model.
Swap the cylinder 4 coil with another cylinder (where the design allows), clear the code and see if the fault follows the coil.
Test the cylinder 4 control circuit for continuity and shorts to earth or voltage, with the connectors disconnected.
Use a scan tool's output test or an oscilloscope to check the ignition control signal from the module, if the system allows it.
Check the spark plug for cylinder 4 for wear or fouling, as it can add to coil stress and misfire.

How to fix

Replace the faulty ignition coil for cylinder 4, and renew the spark plug if it is worn.
Repair or replace damaged wiring in the cylinder 4 ignition control circuit.
Clean or replace corroded or loose connectors and secure terminals properly.
Restore a good power or earth supply to the coil or ignition module.
Replace the ignition control module where fitted and confirmed faulty.
Replace or repair the engine control module only after wiring, coil and supplies are proven good.

Can I keep driving?

Medium severity

Short, gentle journeys are possible, but a misfire can overheat and damage the catalytic converter, so get it fixed soon. If the warning light flashes or the engine runs very roughly, stop driving and have the car recovered or inspected.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.