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Home >> Mercedes Benz >> 1990 >> 300CE >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Testing With On-Off Ratio Tester >> On-Off Ratio Test
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On-Off Ratio Test

  1. Connect On-Off Ratio Tester (Bosch KDJE-P 600) to test socket (on left side of engine compartment). See Fig 1 . Turn ignition on. Perform On-Off Ratio tests. Record results of (0)/0 readout shown on On-Off Ratio Tester. See TROUBLE SHOOTING - IGNITION ON, ENGINE OFF  .
    Fig 1: On-Off Ratio Tester
    G90I17317Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
  2. Start engine and allow to idle. Perform and record results of percentage readout shown on on-off ratio tester. See TROUBLE SHOOTING - ENGINE IDLING  .
  3. After recording (0)/0 readouts from both tests and note test steps to be performed, refer to appropriate test step and correct malfunction. See TEST STEP CHARTS in this article.