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.
BOSCH Cis-E III System: Description
CIS-E III system uses 2 interfacing computers. Ignition Control Unit (ICU) on Audi 90 or Knock Sensor Control Unit (KSCU) on 5000S, controls the ignition system. Fuel Injection Control Unit (FICU) controls fuel injection. CIS-E III system also has self diagnosis and trouble shooting capabilities.
Input and output signals from various sensors, switches and signalling devices are constantly monitored for faults. These faults are stored in memory. Faults can be displayed by a flashing 4-digit code sequence from an LED light located on the instrument cluster.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.