 
    
    Diagnostic Manual, Engines, Volume 4 
    
    
    
    
    
    Electrical Test Program - Preparation for Test 
    
    
      
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              | Preliminary work: Diagnosis - Malfunction Memory  11 
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              |  WARNING! Risk of severe injury when touching ignition parts which produce high voltages. Do not touch ignition components.
 Persons with heart pacemakers are not to perform repairs on this type of ignition system.
 
 1. Review
  11 ,  21 ,  22 ,  23 ,  24 ,  31 ,  33 ,  35 ,  36 , 2. Review section 0,
 3. Connect HHT and readout DTC memory, see
  11 , 4. Ignition: OFF
 5. Connect test cable with socket box to engine control module (N3/11) or engine control module (N3/12), see
  22 /5 
 
   Connect interior harness connector to connection 1 on test cable.
 Connect engine harness connector to connection 2 on test cable.
 
 Note regarding "Test Connection" column:
 The numbers indicated in parentheses, for example,
  1.0  (2A) signify: 2 = Socket 2 on wiring diagram.
 A = Connector A on wiring diagram,
 
 Note:
 The test program is divided into four sections:
 23 SFI Test
 24 Ignition System Test
 25 EA System Test
 26 CC System Test
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             Test Equipment; See MBUSA Standard Equipment Program   
              | Description | Brand, model, etc. |  
              | Digital multimeter | Fluke models 23, 77 III,  83, 85, 87 |  
              | Engine analyzer | Bear DACE Hermann Electronics
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              | To Avoid Damage to the Ignition System 
  To avoid damage to the engine control module, connect/disconnect the control module connectors only with the ignition: OFF . 
  Circuit 1 of the ignition coil may not be shorted to ground, e.g. theft deterence. 
  Only original equipment should be installed in the ignition system. 
  Do not operate the ignition system at cranking speed unless the entire igntion harness is connected. 
  Do not perform any tests (grounding of ignition cable 4 disconnecting a spark plug connector or pulling cable 4 out of the ignition coil) at cranking or idle speed. 
  The high output side of the ignition system must carry at least 2 k  of load (spark plug connector). 
 
  If assisting a disabled vehicle and it becomes necessary to perform an igntion spark test, perform this test only on one ignition/sark plug. Ensure a good ground connection to the spark plug. 
  ME - SFI: the ignition system is to be turned OFF, when cranking engine to perform compression tests, additionally, it is necessary to disconnect connector 2 from the control module. 
 
  Engine 120 has separate ignition and fuel injection system 
 Using Test Equipment
 
  Connect the secondary voltage measuring equipment on the corresponding secondary ignition lead only when engine is stopped and ignition is OFF. 
  If the circuit breaker is activated (power balance test), and the engine stalls, then the test procedure with this tester cannot be performed. 
  Do not connect a test lamp to circuit 1 or 15 of the ignition coil. |  
           
           
           
            
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