Connect jumper harness tool No. 91-41, or equivalent, to pin No.1 of
connector M720 (green two-pin connector, located at right rear corner of
engine compartment). Connect other end of jumper harness to a vehicle
ground.
Diagnostic trouble codes will be displayed through flashing of the
"Check Engine" lamp on the instrument cluster. All defects
detected by the Motronic ECU can be stored in memory simultaneously.
Turn ignition key to "On" position, then depress jumper harness
switch for three seconds. When the switch is released, the "Check
Engine" lamp will flash one time, then it will remain off for 1-5
seconds, then the lamp will flash two more times. This flashing pattern is
indicative of diagnostic trouble code No. 12 (beginning of test sequence).
Wait for the "Check Engine" lamp to come on, then depress jumper
harness switch for three seconds. Any diagnostic trouble codes stored in ECU
memory will be displayed. The "Fuel Pump Relay" (DTC 15),
"Idle Regulation Valve" (DTC 22) and "Engine Speed
Sensor" (DTC 41) are classified as minor defects and the Check Engine
light will not illuminate if a fault is detected. Repeat previous step to
display all diagnostic trouble codes. Diagnostic trouble code No. 11 (end of
test sequence) indicates that all detected DTC's have been displayed.