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.
1988 Mercedes Benz 560SLFACTORY OEM SERVICE PROCEDURE
Cis-E System
- Description
- Operation
- On-Board Diagnostic Readout System
- Fuel Pump Relay
- Cold Start Valve Activation
- Fuel Enrichment
- Fuel Pump
- Fuel Distributor Unit (FDU)
- Coolant Temperature Sensor
- Electronic Control Unit (Ecu)
- Idle Speed Control Unit
- Idle Speed Air Valve
- OVERVOLTAGE Protection Relay
- Oxygen Sensor
- Lambda Control
- EZL Ignition Operation
- On-Board Diagnostic System
- Testing Lambda Control System
- Trouble Shooting
- Notes
- Testing With Impulse Counter
- Notes
- Code 1
- Code 2, Throttle Valve Switch
- Code 3, Coolant Temperature Sensor
- Code 4, Airflow Sensor Position Indicator
- Code 5, Oxygen Sensor
- Code 7, TD-Signal
- Code 8, Altitude Correction Capsule
- Code 9, Electro-Hydraulic Actuator (EHA)
- Code 10, Idle Speed Contact
- Code 12, EGR Temperature Sensor, 420 & 560 (California Only)
- Testing With On-Off Ratio Tester
- Trouble Shooting Charts
- ***Please Read This First***
- Testing OVERVOLTAGE Protection
- Testing Coolant Temperature Sensor
- Check Temperature Sensor Intake Air
- Testing DECEL Shutoff
- Testing Throttle Valve Switch
- Checking Acceleration Enrichment Or Sens. Of Air Volume Meter
- Testing Partial Load Mixture Adaptation, RUF Only
- Testing Speed Signal, Engine 103.942 Only
- Testing Current On Actuator
- Testing Sensor, Altitude Correction (Arrow)
- On-Off Ratio 0%
- On-Off Ratio 10%
- On-Off Ratio 20%
- On-Off Ratio 30%
- On-Off Ratio 40%
- On-Off Ratio 50%
- On-Off Ratio 70%
- On-Off Ratio 80%
- On-Off Ratio 100%
- Component Testing
- Wiring Diagrams
Factory Service Tools
Use the Manual With the Right Hardware
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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.