3315434 - 2135BB Graphic analysis of signal from C.A.E. control unit to instrument panel (Automatic transmission)

Remove the electronic auto transmission control unit (carry out op.   2135B52  electronic automatic transmission electric circuit - r r ). Undo the bolt and remove the cover from the electrical connection comb for the wiring of the electronic auto transmission control unit.Connect the comb to the electronic auto transmission control unit.Set up the diagnostic instrument (Examiner or SDC) for a graphic familiarization under voltage (use the voltmeter function from the instrumentation menu).Connect in parallel the instrument's red lead to pin 25 of the electronic auto transmission control unit comb, and the black lead to earth.Connect the battery's positive (+) terminal and turn the ignition on (MAR).Press the Start icon on the diagnostic instrument to start graphic familiarization.

Throughout the duration of reading, move the auto transmission lever from P to R to N to D and vice versa, pausing at each position for 5 seconds.

After the diagnostic instrument has completed its reading, magnify the diagram and check for the presence of a square-wave signal with variable PWM. If no signal is found, replace the electronic auto transmission control unit (carry out op.   2135B52  electronic automatic transmission electric circuit - r r ). Check that the signal measured with the diagnostic instrument is within the specified values. A, Positive part of the signal B, Negative part of the signal T, Pulse period Note The values B and T are expressed in mm Example of calculation: % = (B/T) x 100 If the signal is within the specified values, replace the instrument panel (carry out op.   5560B11  analogue control panel - r+r or replace ). If the signal is not within the specified values, replace the electronic auto transmission control unit (carry out op.   2135B52  electronic automatic transmission electric circuit - r r