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Engine control unit: replace > < Check conditions

Leon Mk2

Work sequence
Work sequence
–  Connect fault reader -V.A.G 1551- (-V.A.G 1552-). With ignition turned on select “Address code” 01 to select engine electronics control unit.
   
Indicated on display:
–  Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 1 and 2 for “Display group number 12” and confirm entry with Q key.
–  Observe the reading in field 3.
  
Read measured value block               
Enter number group values XXX
Indicated on display: Specification: Battery voltage at least 11.5 V.
–  Press → key.
–  Press keys 0 and 6 for the “End output” function and confirm input with the Q key.
–  Switch off ignition.
If the displayed value oscillates or does not reach battery voltage:
  
Read measured value block 12           →
11111111        0, 0 0   14.1 V   28.5°C
–  Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.
–  Measure supply voltage using multimeter -V.A.G 1526 A- and test leads from -V.A.G 1594 C- between the test box sockets. 1 + 4 and 5, 2 + 4 and 5, 37 + 4 and 5 Specification: approx. 0 V
–  Switch on ignition.
–  Again measure the voltage between connections: 1 + 4 and 5, 2 + 4 and 5, 37 + 4 and 5 Specification: approx. battery voltage 11.5 V
If the specifications are not attained:
–  Checking the relay for the Diesel direct injection system -J322- → Chapter → Current flow diagrams, Electrical fault finding and Fitting locations
–  Check cables for brake, open circuit and transfer resistances at contact points, using current flow diagram.
If no wiring or relay fault is detected:
–  Renew engine control unit → Chapter
  E23-0084

Engine control unit: replace > < Check conditions