Engine Systems (MAS)
Testing with Impulse Counter Scan ToolNote:
The engine systems (MAS) control module (N16) retains memory even with the battery diconnected or the control module unplugged.
Impulse Counter Connection (Model 124, 129, 201):
MAS Control Unit/Impulse Counter Connection (Model 126):
1. Connect the impulse counter scan tool according to connection diagram.
Note: The LED "U Batt" will be illuminated.
- If the LED "U BATT" does not illuminate check for voltage between socket 1 of the on-board diagnostic connector and the positive terminal of the battery. If the voltage is not between 11-14 volts check for an open circuit or loose ground connection.
- Test for voltage between socket 3 and socket 1 of the diagnostic connector. If the voltage is not between 0.7-2.5 volts, check for power to the control unit, the control unit connection or open circuit.
2. Engine at idle.
3. Press start button for 2 - 4 seconds.
4. Read and note DTC readout.
display "1" = no faults stored,
greater than "1" = fault in system.
5. Press start button again for 2 to 4 seconds.
If there are no further faults in the system, the previously displayed DTC will reappear.
If additional faults exist, then the respective DTC will be displayed.
6. Repeat step 5 until the first number displayed is repeated.
7. Note any additional faults from DTC readout.
8. Eliminate all noted faults (DTC readout) according to Trouble Code Descriptions Diagnostic Trouble Code Descriptions and Trouble Code Diagnostic Charts. Testing and Inspection
Erasing DTC Memory
After eliminating a fault, the respective DTC readout must be cleared as follows:
9. Press start button for 2 to 4 seconds and read out the DTC. Then press the start button for 6 to 8 seconds.
Note: Each DTC displayed must be erased individually.
