
144 RENR5622
Troubleshooting Section
2. Repair the wiring and/or the connector. Replace
parts, if neces
sary. Verify that the problem is
resolved.
STOP.
•
Not OK – The voltage measurement is not 5.0 ±
0.2 VDC.
Repair: Replace the ECM. Refer to
Troubleshoot
ing, “Replacing the ECM”.
STOP.
Test Step 5. Di sconnect the 8 Volt
Sensors w hile you Monitor the Active
Diagnostic Codes
A. Monitor the a
ctive diagnostic code screen on Cat
ET while you disconnect each 8 Volt sensor at
the sensor connector. Check for an active 263-03
code or an ac
tive 263-04 code.
Note: Wait at least 30 seconds in order for the
diagnosti
c codes to become active.
a. Disconnect the following sensors one at a time:
•
Exhaust temperature sensor (LH)
•
Exhaust tem
perature sensor (RH)
B. Remove electrical power from the ECM.
Expected Result:
The diagno
stic code deactivates when a particular
sensor is disconnected.
Results:
•
OK – The 263-03 or 263-04 diagnostic
code deact
ivates when a particular sensor is
disconnected.
Repair: Co
nnect the suspect sensor. If the code
returns, replace the sensor. Connect all of the
connectors. V erify that the problem is resolved.
STOP.
•
Not OK – Th
e263-03or263-04diagnosticcode
remains active after the sensors are disconnected.
Leave the sensors disconnected. The sensors are
not the ca
use of the diagnostic code. Proceed to
Test Step 6.
Test Step
6. Check the 8 Volt Supply
Voltage
at the ECM
A. Disconnect the J1/P1 ECM connector.
B. Fabricate two jumper wires that are long enough
to be used to mea
sure the supply voltage at the
ECM connectors. Crimp connector sockets to one
end of each jumper wire.
C. Remove the wires from terminal locations P1-4 (8
V sensor supply) and P1-60 (sensor return). Install
a jumper wire
into each of these terminal locations.
D. Connect the J1/P1 ECM connector.
E. Restore electrical power to the engine ECM.
F. Measure the v
oltage between the jumper wire
in P1-4 (8 V sensor supply) and P1-60 (sensor
return).
G. Remove electrical power from the ECM.
Expected Res
ult:
The voltage measurement is 8.0 ± 0.4 VDC.
Results:
•
OK – The volta
ge measurement is 8.0 ± 0.4 VDC.
The ECM is operating correctly.
Repair: One o
f the supply wires is shorted to
another wire in the harness or one of the supply
wires is shorted to engine ground. To isolate
the problem
to a specific harness, perform the
following test steps:
1. Reinstall t
he wiring for the 8 V supply while you
checkCatETforanactive263-03or263-04
diagnostic code.
a. Disconnect the ECM connector.
b. Install th
e wires that were removed for the
8 V supply at the ECM connector. Refer to
Illustration 67 for wiring information.
c. Connect the ECM connector.
d. Restore el
ectrical power to the engine ECM.
e. Monitor the active diagnostic code screen on
Cat ET. Che
ckforanactive263-03codeor
an active 263-04 code.
Note: Wai
t at least 30 seconds in order for the
diagnostic codes to become active.
f. If a diagn
ostic code becomes active for
this 8 V supply, there is a problem in this
harness between the ECM and the sensor
connecto
r.