HOUSING 7N9062 - Caterpillar

System Operation Description: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
Code and Description Conditions which Generate this Code System Response
262-3 5 Volt Sensor DC Power Supply : Voltage Above Normal The analog sensor supply voltage is above normal for two seconds. The code is logged.
All sensors are set to default values.
262-4 5 Volt Sensor DC Power Supply : Voltage Below Normal The analog sensor supply voltage is below normal for two seconds.
263-3 Digital Sensor Power Supply (8V Or 12V) : Voltage Above Normal The digital sensor supply voltage is above normal for two seconds.
263-4 Digital Sensor Power Supply (8V Or 12V) : Voltage Below Normal The digital sensor supply voltage is below normal for two 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 exhaust temperature sensor
Right exhaust 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, it is possible that all of the sensors 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 g01340556
Typical schematic 5 V supply
Illustration 2 g01340557
Typical schematic 8 V supply
Illustration 3 g01327649
P1 ECM connector
(P1-2) "5 V analog sensor supply (LH)"
(P1-3) "Analog sensor return (LH)"
(P1-4) "8 V digital sensor supply (LH)"
(P1-5) "Digital sensor return (LH)"
(P1-18) "5 V analog sensor supply (RH)"
(P1-35) "Analog sensor return (RH)"
Illustration 4 g01327661
P2 ECM connector
(P2-56) "8 V digital sensor supply (RH)"
(P2-66) "Digital sensor return (RH)"
Illustration 5 g01327616
Terminal locations for the A-C1/E-C2 RH rigid harness connectors and the C-C1/E-C1 LH rigid harness connectors
(Terminal A) "Analog sensor return (RH)"
(Terminal B) "5 V analog sensor supply (RH)"
(Terminal C) "8 V digital sensor supply (RH)"
(Terminal D) "Digital sensor return (RH)"
Illustration 6 g01356892
Terminal locations for the AA-C67C-C20 connector for the fuel pressure sensors and for the oil pressure sensors
(Terminal B) "Analog return (LH)"
(Terminal C) "5 V analog sensor supply (LH)"
Illustration 7 g01356894
Terminal locations for the A-C48 connector for the coolant level sensors
(Terminal A) "8VDC digital supply"
(Terminal B) "Digital return"
Illustration 8 g01337991
Connector locations
(1) A-C1/E-C2 RH rigid harness connectors
(2) A-C2/J-C2 RH rigid harness connectors
(3) P-C1/A-C90 Connectors for the power distribution