DDEC TROUBLESHOOTING
10.14.8 Check Park Brake Switch
Perform the following steps to troubleshoot the park brake switch and other OEM interlock
devices.
1. Check the park brake switch and other OEM interlock devices (e.g. high-range switch).
2. Measure resistance across the park brake switch contacts with the park brake set.
[a] If the measured resistance is less than 100 , the 953 ground wire is open somewhere
between the ECM and the battery. Repair the open. Refer to section 10.14.11.
[b] If the measured resistance is more than 100 , replace the park brake switch or other
OEM interlock devices. Refer to section 10.14.11.
10.14.9 Check the Thermostat
Perform the following steps to check the thermostat operation:
1. Turn ignition ON.
2. Plug in the DDR.
3. Select switch light status OPIDL T-STAT.
[a] If the display reads ON with the thermostat enabled and the alarm is turned ON and
the reader shows the switch status for the starter as ON after the alarm turns OFF,
check the relay and starter solenoid connections. Refer to section 10.14.11.
[b] If the display reads ON with the thermostat enabled and the alarm is turned ON and
the reader does not show the switch status for the starter as ON after the alarm turns
OFF, refer to section 10.14.10.
[c] If the display reads ON with the thermostat enabled and the alarm OFF, replace
the alarm. Refer to section 10.14.11.
[d] If the display does not read ON with the thermostat enabled, the thermostat
input wire #958 is open between the thermostat and the ECM. Repair the open.
Refer to section 10.14.11.
10.14.10 Oil Temperature Sensor Connection Check
Perform the following steps to troubleshoot the OTS connection:
1. Check the OTS connection.
[a] If the OTS connector is plugged into the oil temperature sensor, reprogram the
ECM. Refer to section 10.14.11.
[b] If the OTS connector is not plugged into the OTS, plug in the OTS connector.
Refer to section 10.14.11.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
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