Open circuit, broken wire or high resistance in the ignition coil control signal wiring; Corroded, loose or damaged connector terminals at the coil or the control unit; Faulty ignition coil, or coil with integral driver, that fails to respond to the control signal; Missing or poor power supply or earth to the coil or its driver; Wiring chafed or heat-damaged near the engine, or damaged by previous repair work; Internal fault in the engine control unit output driver.

P036A

Ignition G Control Signal Circuit/Open.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
6A: FaultThe specific fault in that area

What it means

P036A is the generic code for an open circuit in the control signal circuit for ignition coil or ignition channel 'G'. The engine control unit commands that ignition output but detects no response, or a signal outside the expected range, which points to an open circuit between the control unit and the coil driver. Which cylinder 'G' refers to depends on the manufacturer and engine, so check the vehicle-specific information.

Symptoms

Engine misfire on one cylinder, often rough running at idle
Malfunction indicator lamp on, possibly flashing under load
Hesitation or loss of power when accelerating
Hard starting or extended cranking
Increased fuel consumption
Engine may run in a reduced-power mode

Possible causes

Open circuit, broken wire or high resistance in the ignition coil control signal wiringlikely
Corroded, loose or damaged connector terminals at the coil or the control unitlikely
Faulty ignition coil, or coil with integral driver, that fails to respond to the control signalpossible
Missing or poor power supply or earth to the coil or its driverpossible
Wiring chafed or heat-damaged near the engine, or damaged by previous repair workpossible
Internal fault in the engine control unit output driverrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine load, speed and temperature when the fault set. Check for related misfire codes.
Identify which cylinder or coil is 'G' for this engine using manufacturer data, as the layout varies by model.
Visually inspect the coil connector, wiring loom and plug for damage, corrosion, heat damage, water ingress or poor terminal tension.
Check the coil power supply and earth connections with a multimeter, following the wiring diagram for the vehicle.
Swap the suspect coil with a known good one from another cylinder and see whether the fault or any misfire follows it.
With the ignition off and the control unit connector disconnected where the manufacturer procedure allows, test the control signal wire for continuity and for shorts to earth or supply.
Use an oscilloscope or the manufacturer's actuator test to confirm the control unit is sending a signal at the coil connector.
Inspect spark plugs for the affected cylinder, as worn plugs can stress the coil, and check for related fault history.

How to fix

Repair or replace the damaged section of wiring, using proper soldered and sealed joints or a manufacturer-approved repair.
Clean, repair or replace corroded or loose connector terminals and housings.
Replace the faulty ignition coil, and renew spark plugs if they are worn or fouled.
Restore the correct power supply or earth to the coil circuit.
If all wiring and the coil test good and the signal is absent, have the control unit tested and repaired or replaced per manufacturer procedure.

Can I keep driving?

Medium severity

Short, gentle journeys are possible, but a misfiring cylinder can overheat and damage the catalytic converter, so get it fixed soon. If the warning lamp flashes, reduce load and stop driving as soon as it is safe.

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