
72 RENR5622
Troubleshooting Section
F. Remove electrical power from the ECM.
Expected Result:
A 04 diagnostic
code is now active for the suspect
sensor(s).
Results:
•
OK – A 03 diagnostic code was active before
creating the s
hort at the sensor connector. A 04
diagnostic code became active after creating the
short at the sensor connector. The harness and
theECMareOK
. There may be a problem with
the sensor.
Repair: Temp
orarily connect a new sensor to the
harness, but do not install the new sensor in the
engine. Verify that 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 – A 03 diagnostic code is still active for
the suspect sensor(s). The problem may be in the
harness or w
ith the ECM. Proceed to Test Step 6.
Test Step 5. Create an Open at the
Suspect Sensor Connector
A. Remove electrical power from the ECM.
B. Disconnec
t the sensor connector of the suspect
sensor(s) with the active 04 diagnostic code.
C. Restore el
ectrical power to the ECM.
D. Monitor the diagnostic codes on Cat ET. Check
for an acti
ve 03 diagnostic code for the suspect
sensor.
Note: Wai
t at least 30 seconds in order for the
diagnostic codes to become active.
E. Remove el
ectrical power from the ECM.
Expected Result:
A 03 diagnostic code is now active for the suspect
sensor(s).
Results:
•
OK – A 04 di
agnostic code was active before
disconnecting the sensor. A 03 diagnostic code
became active after disconnecting the sensor. The
harness
and the ECM are OK. There may be a
problem with the sensor.
Repair: Temporarily connect a new sensor to the
harness, but do
not install the new sensor in the
engine. Verify that there are no active diagnostic
codes for the sensor. If there are no active
diagnostic co
des for the sensor, permanently
install the new sensor. Clear any logged diagnostic
codes.
STOP.
•
Not OK – A 04 di
agnostic code is still active for the
suspect sensor. Leave the sensor disconnected.
The problem may be in the harness or with the
ECM. Proceed
to Test Step 6.
Test Step 6. Check the Operation of the
ECM
A. Remove electrical power from the ECM.
B. Check the op
eration of the ECM by creating an
open at the ECM.
a. Remove the s
ignal wire for the suspect sensor
fromtheP1orP2ECMconnector.Referto
Illustration 14 for terminal locations.
b. Install a jumper wire with Deutsch sockets on
each end into the socket for the signal wire of
the suspec
tsensor.
c. Reconnect the ECM connectors.
d. Restore electrical power to the ECM.
e. Monitor th
e “Active Diagnostic Code” screen on
Cat ET. Wait at least 30 seconds for activation
of the code.
An open circuit diagnostic code 03 should be
active for the suspect sensor.
C. Check the operation of the ECM by creating a
shortattheECM.
a. Install a wire jumper between the wire jumper
for the signal wire for the suspect sensor and
engine gr
ound.
b. Monitor the “Active Diagnostic Code” screen on
Cat ET. W
ait at least 30 seconds for activation
of the code.
A04diag
nostic code should be active when
the wire jumper is installed.
c. Remove t
he wire jumper. Reconnect all wires
and connectors.