350-02306-0 Tohatsu INNER GASKET

Table 1
Diagnostic Codes Table    
Code    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.     The code is logged.
All sensors are set to default values.    
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 0.5 VDC to the following sensors:
Atmospheric pressure sensor
Coolant temperature sensor
Aftercooler temperature sensor
Crankcase pressure sensor
Filtered engine oil pressure sensor
Left turbocharger inlet pressure sensor
Right turbocharger inlet pressure sensor
Turbocharger outlet pressure sensor
Unfiltered engine oil 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, all of the sensors may 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 g02580342
Typical schematic of 5 V supply
Illustration 2 g01542213
Typical schematic of 8 V supplyTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Illustration 3 g01234146
Location of ECM connectors
Thoroughly inspect the J1/P1 ECM connector and the J2/P2 ECM connector. Inspect all of the connectors that are associated with the circuit.Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g01573094
P1 ECM connector (P1-2) 5 V sensor supply (P1-3) Sensor return (P1-7) Coolant temperature sensor (P1-11) Left exhaust temperature sensor (P1-12) Right exhaust temperature sensor (P1-16) Filtered engine oil pressure sensor (P1-17) Unfiltered engine oil pressure sensor (P1-18) 5 V sensor supply (P1-35) Sensor return (P1-60) Digital return
Illustration 5 g02595628
P2 ECM connector (P2-36) Turbocharger outlet pressure sensor (P2-37) Atmospheric pressure sensor (P2-38) Left turbocharger inlet pressure sensor (P2-39) Right turbocharger inlet pressure sensor (P2-46) Crankcase pressure sensor (P2-55) Digital return (P2-56) 8 V supply (P2-57) 8 V supply
Illustration 6 g01094844
Sensor connector (Pin A) Sensor supply (Pin B) Sensor return (Pin C) Signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.Expected Result:All connectors, pins, and sockets are coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Look for the following diagnostic codes:
262-3
262-4
263-3
263-4 Note: Wait at least 30 seconds in order for the diagnostic codes to become active.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic code is active.Repair: The problem is no longer present. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Either the 262-3 or 262-4 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - Either the 263-3 or 263-4 diagnostic code is active at this time. Proceed to Test Step 5.Test Step 3. Disconnect the 5 V Sensors while you Monitor the Active Diagnostic Codes
Monitor the active diagnostic code screen on Cat ET while you disconnect each 5 V sensor at the sensor connector. If the problem is in a sensor, the active 262-3 code or the active 262-4 code will deactivate when you disconnect the sensor.Note: Wait at least 30 seconds in order for the diagnostic codes to deactivate.
Disconnect the following sensors one at a time: