KENR9126 145
Troubleshooting Section
F. Measure the voltage between P1-15 (Unswitched
Positive Batte
ry) and P1-3 (Negative Battery).
G. Measure the voltage between P1-40 (Keyswitch)
and P1-3 (Nega
tive Battery).
Expected Result:
The measured voltage is between 11.0 VDC and 13.5
VDC for a 12 volt system and between 22.0 VDC and
27.0 VDC for
a 24 volt system w ith no suspected
intermittent problems at this time.
Results:
•
OK – The ECM is receiving the correct voltage.
Repair: If an intermittent condition is
suspected, refer to the diagnostic functional test
Troublesh
ooting, “Electrical Connectors - Inspect”.
STOP.
•
Not OK – The voltage is not correct at the ECM.
Proceed to Test Step 3.
•
Keyswitch voltage out of range – Proceed to Test
Step 4.
Test Step 3. Check the Batteries
A. Measure
the no-load battery voltage at the battery
posts.
B. Load te
st the batteries.
Expected Result:
The batteries pass the load test. The measured
voltage is the minimum specification for a 12V or 24V
syste
m.
Results:
•
OK – The batteries are OK.
Repa
ir: There is an open circuit or excessive
resistance in the wiring or connections between
the batteries and the ECM. Verify that the 20 Amp
cir
cuit breaker for the ECM is not blown. Check
the connections at the customer connector. Verify
that the connection for the engine ground is clean
and
tight and that the battery disconnect switch
is functioning properly. Repair the connectors or
wiring and/or replace the connectors or wiring.
STOP.
•
No
t OK – The battery voltage is low or the battery
did not pass the load test.
Repair: Recharge or replace the faulty batteries.
Verify that the
repair eliminates the problem.
STOP.
Test Step 4. Check the Voltage from the
KeyswitchtotheECM
A. Remove the e
lectrical power from the ECM.
B. RemovethewirefromtheterminalRofthe
keyswitch.
C. Restore the electrical power to the ECM.
D. Measure the voltage on terminal B of the keyswitch
to engine ground.
E. Measure the voltage on terminal R of the
keyswitchtoengineground.
F. Remove the electrical power from the ECM.
Expecte
dResult:
Voltage is present on terminal B and terminal R at
the keys
witch.
Results:
•
OK – Voltage is present on terminal B and terminal
R at the keyswitch.
Repair: If voltage is present on terminal R, repair
thewirebetweenthekeyswitchandtheECM.
Verif
y that the problem is eliminated.
STOP.
•
Not OK – Voltage is not present on terminal B at
the keyswitch.
Repair: If voltage is not present on terminal B,
repair the wire between the +Battery and the
keys
witch. Verify that the fuse for the keyswitch is
not blown. Verify that the problem is eliminated.
STO
P.
•
Not OK – Voltage is not present on terminal R at
the
keyswitch.
Repair: If voltage is present on terminal B of the
ke
yswitch but not present on terminal R, replace
the keyswitch. Return all wiring to the original
configuration. Verify that the problem is eliminated.
STOP.
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