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Home >> Mercedes Benz >> 1988 >> 300SEL (126.025) L6-3.0L (103.981) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Component Tests and General Diagnostics >> Component Tests >> Lambda Control Test >> Federal

Federal


Test Data
On-off ratio
- Test on-off ratio at 2,500 rpm and record the average value. It should not deviate from the average idle speed value by more than ±10.

Special Tools:





Onboard Diagnostic Readout Via On-off Ratio Tester
Various components of the CIS-E injection system are checked via the microprocessor in the CIS-E control unit. The failure codes are transmitted via the lambda measuring circuit of the diagnostic socket and are shown on the on-off ratio tester. The fixed on-off ratio indicates possible malfunctions.

NOTE: The CIS-E control unit with on-board diagnostic readout was not installed in early 1986 production vehicles with engine 103.983. To determine if vehicle is equipped with failure code feature, install on-off ratio tester; turn ignition "ON"; if needle indicates 100%, vehicle does not have failure code feature.





N3 CIS-E control unit
P On-off ratio tester
X11 Diagnostic socket

Test Procedure:




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