
146 RENR9348-01
Troubleshooting Section
Test Step 4. Shor t at the Suspect Sensor
at the Harness Connector
A. Remove electrical power from the ECM.
B. Disconnect th
e suspect sensor at the harness
connector.
C. Fabricateaju
mper wire that is long enough to
short circuit the two terminals at the connector for
the suspect sensor. Crimp connector pins to each
end of the jum
per wire.
D. Install the jumper wire between terminal 1 (sensor
signal) and t
erminal 2 (sensor return) on the
harness side of the suspect sensor’s connector.
E. Rest ore elec
trical power to the ECM.
F. Monitor the “Active Diagnostic Codes” screen on
Cat ET af ter i
nstalling the jumper wire. Check for
an active 04 diagnostic code.
Note: Wait a
t least 30 seconds for activation of the
04 diagnostic code.
G. Remove elec
trical power from the ECM.
Expected Result:
A 04 diagnostic code is now active for the suspect
sensor.
Results:
•
OK – A 04 dia
gnostic code is active when the
jumper wire is installed.
Repair: Th
ere may be a problem with the sensor.
Temporarily connect a new sensor to the harness,
but do not install the new sensor in the engine.
Verify tha
t there are no active diagnostic codes for
the sensor. If there are no active diagnostic codes
for the sensor, permanently install the new sensor.
Clear any
logged diagnostic codes.
STOP.
•
Not OK – The 03 diagnostic code remains active
with the jumper in place. There is an open circuit
between t
he ECM and the sensor connector. There
may be a problem with the ECM. Proceed to Test
Step 5.
Test Step 5. Check the Operation of the
ECM
A. Remove e
lectrical power from the ECM.
B. Check the operation of the ECM by creating
an open a
ttheECM:
a. Disconnect the J2/P2 ECM connector.
b. Fabricate a jumper wire that is long enough to
create a test circuit from the ECM connector
totheengineg
round stud. Crimp a connector
socket to one end of the jumper wire.
c. Remove the sig
nal wire for the suspect sensor
from the J2/P2 ECM connector. Install the
jumper wire into this terminal location.
d. Connect the ECM connectors.
Hold the loos
e end of the jumper wire away
from any ground source in order to create an
open circuit condition.
e. Restore electrical power to the ECM.
f. Monitor the “
Active Diagnostic Code” screen
on Cat ET. A 03 diagnostic code will become
active for the suspect sensor.
Note: Wait at least 30 seconds for activation of the
code.
g. Remove electrical power from the ECM.
C. Check the o p
eration of the ECM by creating a
shortattheECM.
a. Connect the
loose end of the jumper wire to the
engine ground stud in order to create a short
circuit condition.
b. Restore electrical power to the ECM.
c. Monitor th
e “Active Diagnostic Code” screen
on Cat ET. A 04 diagnostic code will become
active when the jumper wire is grounded.
Note: Wait at least 30 seconds for activation of the
code.
d. Remove electrical power from the ECM.
D. Restore al
l wiring to the original configuration.
Expected Result:
A 04 diagnostic code becomes active when the signal
wire is shorted to the engine ground stud.
Results:
•
OK – A 03 dia
gnosticcodeisactivewhenthe
signal wire is open. A 04 diagnostic code is active
when the signal wire is shorted to ground.