Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Optical Ignition System Checks (G20 & M30): Spark
Check for spark at coil wire and each spark plug wire using a spark tester. Crank engine in short bursts. DO NOT crank engine more than 2 seconds continuously. Inspect secondary coil wire for arcing while testing spark at plugs. Check spark plug wire resistance on suspect wires. Resistance should not be more than 30,000 ohms. Coil wire resistance should not be more than 7000 ohms. Check connections at crank angle sensor, ignition coil and power transistor.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.