0389631 JOHNSON GEARCASE ASSY.,Std.

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
827-8 Left Exhaust Temperature signal abnormal The Electronic Control Module (ECM) detects a sensor frequency that is greater than 1000 Hz or less than 150 Hz.
The ECM detects a duty cycle that is greater than 90 percent or a duty cycle that is less than 10 percent. The value of the parameter is set to zero.
The code is logged.
828-8 Right Exhaust Temperature signal abnormal The ECM detects a sensor frequency that is greater than 1000 Hz or less than 150 Hz.
The ECM detects a duty cycle that is greater than 90 percent or a duty cycle that is less than 10 percent. System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Left exhaust temperature sensor
Right exhaust temperature sensorA digital supply voltage is routed to terminal A of each sensor connector. The sensor return is routed to terminal B of each sensor connector. The sensor signal is routed to terminal C of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.
Illustration 1 g01213936
Schematic for the pulse width modulated sensors
Illustration 2 g01228528
P1 ECM connector
(P1-4) 8 V supply
(P1-5) Digital return
(P1-11) Left exhaust temperature
(P1-12) Right exhaust temperature
Illustration 3 g01159881
Sensor connector
(Terminal A) Sensor supply
(Terminal B) Sensor return
(Terminal C) Signal
Illustration 4 g01228531
Location of the exhaust temperature sensors (typical right side and left side engine views)
(1) Right exhaust temperature sensor
(2) Left exhaust temperature sensor Test Step 1. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes. Note: Wait