BOLT 5Q3561 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the following diagnostic codes:
262-3 5 Volt Sensor DC Power Supply : Voltage Above Normal
262-4 5 Volt Sensor DC Power Supply : Voltage Below NormalThe Electronic Control Module (ECM) supplies 5.0 0.5 VDC to the following components:
Inlet air temperature sensor
Engine oil temperature sensor
Unfiltered engine oil pressure sensor
Filtered engine oil pressure sensor
Desired speed potentiometer (if equipped)For the sensor circuits, a 262-3 diagnostic code is probably caused by a short circuit to a higher voltage source in the harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.For the desired speed potentiometer circuit, a 262-3 diagnostic code will be activated if either of these conditions occur:
A short in the wiring for the desired speed signal to a voltage that is greater than +5 VDC
Adjustment of the desired speed potentiometer near the maximum desired speedFor the sensor circuits, a 262-4 code is probably caused by a short circuit to ground in the engine harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.For the desired speed potentiometer circuit, a 262-4 diagnostic code will be activated if either of these conditions occur:
A short in the wiring for the desired speed signal to ground
Adjustment of the desired speed potentiometer near the minimum desired speedThis troubleshooting procedure may generate additional diagnostic codes. Continue to troubleshoot the cause of the original diagnostic code before troubleshooting other codes. Clear the diagnostic codes after the problem is resolved.A 262-4 diagnostic code will be activated if both of these conditions occur:
Illustration 1 g02338548
Schematic for the 5 V supplyTest Step 1. Inspect the Electrical Connectors and the Wiring
Set the engine control to the OFF/RESET position.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
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Top view of the front of the engine (1) Inlet air temperature sensor (2) Pressure sensor for unfiltered oil (3) Pressure sensor for filtered oil (4) Oil temperature sensor
Illustration 3 g02339137
Typical location of the desired speed potentiometer (typical display panel)
Illustration 4 g01393788
Location of the ECM connectors for the 5 V supply(typical left front engine view) (5) J1/P1 ECM connectors
Illustration 5 g01393791
Location of connectors for the 5 V supply(typical left rear engine view) (6) Engine interface connector
Thoroughly inspect the connectors for sensors (1), (2), (3), and (4). Also, thoroughly inspect the connector for the desired speed potentiometer, ECM connectors (5), and engine interface connector (6) .
Check the allen head screws for each of the ECM connectors and the engine interface connector for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the correct torque value.
Illustration 6 g01393742
Terminal locations at the P1 ECM connector for the sensor supply circuit (P1-2) 5 V supply (P1-3) Return (P1-18) 5 V supply (P1-35) Return
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Terminal locations at the engine interface connector for the sensor supply circuit (Terminal 6) 5 V supply (Terminal 8) Return
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Terminal locations at the sensor connector for the sensor supply circuit (Terminal A) 5 V supply (Terminal B) Return (Terminal C) Signal
Illustration 9 g02337298
Terminal locations