GASKET 6L4435 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with a sensor supply or if any one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
262-3 5 Volt Sensor DC Power Supply short to +batt The analog sensor supply voltage is above normal for 2 seconds. The code is logged.
All sensors are set to default values.
262-4 5 Volt Sensor DC Power Supply short to ground The analog sensor supply voltage is below normal for 2 seconds.
263-3 Digital Sensor Supply short to +batt The digital sensor supply voltage is above normal for 2 seconds.
263-4 Digital Sensor Supply short to ground The digital sensor supply voltage is below normal for 2 seconds. System OperationThe Electronic Control Module (ECM) supplies a regulated voltage of 5.0 0.2 VDC to the following sensors:
Aftercooler temperature sensor
Atmospheric pressure sensor
Coolant temperature sensor
Crankcase pressure sensor
Filtered engine oil pressure sensor
Filtered fuel pressure sensor
Turbocharger outlet pressure sensor
Left turbocharger inlet pressure sensor
Right turbocharger inlet pressure sensor
Unfiltered engine oil pressure sensor
Unfiltered fuel pressure sensorThe ECM supplies a regulated voltage of 8.0 0.4 VDC to the following sensors:
Left turbocharger turbine inlet temperature sensor
Right turbocharger turbine inlet temperature sensorThe supply voltage for the sensors is routed from the ECM to terminal A of each sensor connector. The sensor return for the sensors is routed from the ECM to terminal B 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.Note: The sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. If the diagnostic code 262-3 or the diagnostic code 263-3 is logged, all of the sensors could have been damaged. Repair the sensor supply and check for any active sensor diagnostic codes in order to determine if a sensor has failed.
Illustration 1 g03317117
Typical schematic for the +5V supply sensors
Illustration 2 g03318025
Typical schematic for the +8V supply sensors
Illustration 3 g03323203
Terminal locations at the P1 ECM connector
(P1-2) Analog supply
(P1-3) Analog return
(P1-4) Digital Supply
(P1-5) Digital Return
(P1-11) Left-hand turbo inlet exhaust temperature
(P1-12) Right-hand turbo inlet exhaust temperature
(P1-16) Filtered oil pressure
(P1-17) Unfiltered oil pressure
(P1-24) Filtered fuel pressure
(P1-25) Unfiltered fuel pressure
(P1-35) Analog return
(P1-39) Analog supply
Illustration 4 g03323204
Terminal locations at the P2 ECM connector.
(P2-36) Turbo outlet pressure
(P2-37) Atmospheric pressure
(P2-38) Left turbo inlet pressure
(P2-39) Right turbo inlet pressure
(P2-46) Crankcase pressure
(P2-54) Digital return
(P2-56) Digital supply
Illustration 5 g01240891
Sensor connector
(Terminal 1) Sensor supply
(Terminal 2) Sensor return
(Terminal 3) Signal
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect connectors (1) through (7). Inspect all of the connectors that are associated with the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
D. Check the allen head screw for each of the ECM connectors for the proper