Volvo DH10A 245, Service Manual

Page: 37 / 162

36
Charge pressure
Electrical testing (multimeter)
Special tools:
(999) 6899 Test box
6931 Adapter
8180 Adapter
(951) 0060 Multimeter
Nine pin test socket
Unorm = x
If the meassuring is done at a temperature other
than +20
°
C, adjust the Unorm according to the
table on the following page.
Measured
volts,
charge pressure
Measured
reference
voltage
5
8180
Test box
EDC
control unit
The charge pressure is checked in two stages; on the
engine switched off and on it when driving. The volt-
age measured corresponds to a kPa measuring value.
Connect-up as in figure.
Measure between the measuring points on the test box
6899.
As alternative, measuring can be done directly in the
nine-pin test socket.
1. Measuring on engine switched off
Measuring with the engine switched off ensures that
the charge pressure sensor gives a measuring value that
agrees with the “should” value (see Specifications),
providing the charge pressure sensor is functioning
properly, and that gives us a reference voltage which
corresponds to the voltage measured between the
charge pressure sensor and the control unit.
The measuring is done as follows with the engine off
and the start key (feed selector switch) in Drive posi-
tion:
Measuring on text box (6899)
–
measuring points 1–4, reference voltage
– measuring points 3–4, charge pressure (voltage)
Compare with the “should” values in the specifications
for the respective engine.
Correction of measured values
In order to be able to compare the measured volt value
for max. charge pressure with the value given in the
specifications for the respective engine, the value may
have to be corrected because the reference value can
vary. We call the new value the Unorm value (Unorm).
If the measuring is done at an ambient temperature oth-
er than +20
°
C, the measured value must be corrected
(see table on next page).
The corrected voltage is then compared to the charge
pressure voltage given in the Specifications.
2. Measuring on engine during driving
The engine should be max. loaded during driving in or-
der to come up to max. turbo pressure (see instructions,
page 35).
Measuring is done in the same way and between the
same pins as above.
6899
Nine pin
test socket
6931