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Home >> Mercedes Benz >> 1991 >> 560SEC >> 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 diagnostic socket (Circuit TD, located on left side of engine compartment). See Figure . Turn ignition on. Perform On-Off Ratio tests. Record results of "%" readout shown on On-Off Ratio Tester. See TROUBLE SHOOTING - IGNITION ON, ENGINE OFF TABLE.
  2. Start engine and allow to idle. Perform and record results of percentage readout shown on on-off ratio tester. See TROUBLE SHOOTING - ENGINE AT IDLE  table.
  3. After recording % readouts from both tests and note test steps to be performed, refer to appropriate test step and correct the malfunction. See TEST STEP CHARTS. Refer to the following list.