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.
1991 Audi 100 BaseFACTORY OEM SERVICE PROCEDURE
Primary Resistance
- On version 1, disconnect ignition coil power stage connector and ignition coil wire. See Figure . On version 2, disconnect ignition coil power stage connector and remove screw from top of assembly. See Figure .
- On both versions, connect Multimeter (US 1119) between ignition coil positive (+) and negative () terminals. See Figure and Figure . Reading should be .5-1.5 ohms. If reading is not as specified, replace ignition coil.
- If primary resistance is within specification but there is no ignition, replace ignition coil and power stage as an assembly.
Factory Service Tools
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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.