
136 RENR9348-01
Troubleshooting Section
Repair: There is a problem with the sensor.
Temporarily co
nnect 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 – The 03
diagnostic code remains active
with the jumper in place. There is a problem in
the harness between the ECM and the sensor
connector. T
here may be a problem with the ECM.
Proceed to Test Step 6.
Test Step 6. T
est the Operation of the
ECM
A. Remove electrical power from the ECM.
B. Fabricate a jumper wire that is long enough to
create a test circuit from the ECM connector to the
engine gro
und stud. Crimp a connector socket to
one end of the jumper wire.
C. Disconnec
t the P2 ECM connector.
D. Remove the suspect sensor’s signal wire from the
ECM connec
tor. Install the jumper wire into this
terminal location at the ECM connector.
E. Connect th
e ECM connectors.
F. Check the operation of the ECM by creating
an open at
the ECM:
a. Hold the loose end of the jumper wire away
from any g
round source in order to create an
open circuit condition.
b. Restore e
lectrical power to the ECM.
c. Monitor the “Active Diagnostic Code” screen
on Cat ET.
Check the suspect sensor for an
active 03 diagnostic code.
Note: Wai
t at least 30 seconds so that any codes
may become active.
d. Remove e
lectrical power from the ECM.
G. Check the operation of the ECM by creating a
short ci
rcuit at the ECM:
a. Connect the jumper wire to the engine ground
stud.
b. Restore electrical power to the ECM.
c. Monitor the “Active Diagnostic Code” screen
on Cat ET. Check
the suspect sensor for an
active 04 diagnostic code while the jumper wire
is installed.
Note: Wait at least 30 seconds so that any codes
may become active.
d. Remove electrical power from the ECM.
H. Remove the jum
per wire. Return all wiring to the
original configuration.
Expected Res
ult:
A 03 diagnostic code is active when the sensor
signal wire i
s removed from the ECM connector. A
04 diagnostic code is active when the signal wire is
connected to the engine ground stud.
Results:
•
OK – A 03 diagn
osticcodeisactivewhenthe
sensor signal wire is removed from the ECM
connector. A 04 diagnostic code is active when the
signal wire
is connected to the engine ground stud.
Repair: The ECM is operating properly. The
problem is i
n the harness wiring between the ECM
and the sensor connector.
If the code i
s active for more than one sensor, the
problem is most likely in the return wire for the
sensor. Repair the return wire for the sensor or
replace th
e harness.
STOP.
•
Not OK – One of the following conditions exists:
The 03 diagnostic code is not active when the
sensor sig
nal wire is disconnected. The 04
diagnostic code is not active when the wire jumper
is installed.
Repair: There is a problem with the ECM. Replace
the ECM. Refer to Troubleshooting, “Replacing
the ECM”.
STOP.