300SDL (126.125) L6-3.0L DSL Turbo (603.961) (1987)
EGR Backpressure Transducer: Testing and Inspection
Vacuum Transducer
FIG. 73, Vacuum Transducer mbar / mA Values
Vacuum transducer
a. Connect a vacuum gauge, with a 'T' fitting, to the EGR valve.
b. Connect a multimeter, with the proper test cable, between the vacuum transducer and the wiring harness.
c. Run the engine and increase rpm until a vacuum reading of approx. 250 mbar is obtained.
d. See Fig. 73 for mA / vacuum values.
e. If current at the vacuum transducer is too low, check to see that the vent line to the passenger compartment, and its filter are open.
f.
If the current is too high;
1. Check if the vacuum supply line is blocked.
2. Check if the vacuum line between vacuum transducer and EGR valve is interrupted.