7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS 289
Operational Diagnostics
Operational Diagnostic tests use the
MasterDiagnostics® Continuous Monitor Test.
For help, see “Diagnostic Software Operation”
in Section 3 (page 68) for procedure to run the
Continuous Monitor Test.
V
REF
Tests u sing MasterDiagnostics®
1. Plug the Electronic Service Tool (EST) tool into
the American Trucking Association (ATA) datalink
connector and start MasterDiagnostics®.
2. Disconnect sensor to be tested.
3. Connect breakout harness to harness only.
4. TurntheignitionswitchtoON.
5. Monitor signal voltage with the EST using
continuous monitor session and initiating KOEO
Continuous Monitor Test.
Voltage should be n ear 0 , unle ss the signal circuit
isshortedorincorrectlywiredtoV
REF
, B+, or other
voltage sources. See C ircuit Diagnostics in this
section for sensor specifications .
6. Use a Digital Multimeter (D MM) to verify V
REF
at BLUE pin (V
REF
) in bre akout harness (voltage
should be 5 V ± 0.5 V). Connect positive to BLUE
and negative to chassis g round.
If voltage is greater than 5.5 V, check V
REF
for short
to B+.
If vo ltage is less than 4.5 V, c heck V
REF
for open or
short to ground.
7. Install 500 ohm harness between GREEN (signal
circuit), and BLUE (V
REF
) pin of breakout harness.
Monitor signal voltage with EST.
If voltage is less than 4.5 V, check signal c ircuit for
open or short to ground.
8. Use a DM M to check resistance from BLACK p in
(signal ground) of breakout harness to chassis
ground.
If resistance is greater 5 ohm, check for open
or high resistance between ECM and sensor
connector.
9. Connect engine or chassis harness to sensor.
10. Use the EST to clear DTCs.
If an active DTC remains after checking test
conditions, replace sensor.
Temperature Sensor Tests using
MasterDiagnostics®
1. Plug the Electronic Service Tool (EST) tool into the
ATA connector and start MasterDiagnostics®.
2. Disconnect sensor to be tested.
3. Connect breakout harness to harness only.
4. Turn the ignition switch to ON.
5. Monitor signal volt ag e with th e EST using
continuous monitor session and initiating KOEO
Continuous Monitor Test (voltage should be
greater than 4.6 V). See Circuit Diagnostics in
this section for sensor specifications.
If voltage is less than 4.6 V, check signal circuit for
short to ground.
If voltage is greater than 5.5 V, check signal circuit
for short to B+.
6. Install 3–Banana plug harness between GREEN
(signal circuit), and BLACK (signal ground) pin of
breakout harness.
If voltage is more than 0.127 V, check ground
circuit for open or high resistance. See
Circuit Diagnostics in this section for sensor
specifications.
7. Remove 3–Banana plug harness.
8. Connect engine or chassis harness to sensor.
9. Use the EST to clear DTCs.
If an active DTC remains after checking test
conditions, replace sensor.
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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