Ignition H Control Signal Circuit/Open

Common symptoms

What you'll notice

• Check and replace a faulty ignition coil
• Inspect and repair any loose or damaged wiring in the ignition system
• Verify and fix any faulty connections or terminals in the ignition control module
• Test and replace a defective ignition control module
• If necessary, replace the Engine Control Unit (ECU) to resolve the issue

Common causes

Most likely first

1. Faulty ignition coil
2. Malfunctioning ignition control module
3. Loose or damaged ignition coil connector
4. Faulty ignition coil driver circuit
5. Issue with the engine control module (ECM)

How to diagnose & fix

Work through it in order

1. Engine misfires or runs roughly
2. Decreased fuel efficiency
3. Difficulty starting the engine
4. Stalling or hesitation while driving
5. Illumination of the Check Engine Light