98AB-50-670 Tohatsu HOSE

Table 1
Diagnostic Codes Table
Code Conditions which Generate this Code System Response
41-3 8 Volt DC Supply : Voltage Above Normal The 8 volt power supply is above normal for two seconds. The code is logged.
The alarm output is activated.
The shutdown output is activated.
The engine is shut down.
41-4 8 Volt DC Supply : Voltage Below Normal The 8 volt power supply is below normal for two seconds.
262-3 5 Volt Sensor DC Power Supply : Voltage Above Normal The 5 volt power supply is above normal for two seconds.
262-4 5 Volt Sensor DC Power Supply : Voltage Below Normal The 5 volt power supply is below normal for two seconds. Refer to Troubleshooting, "Component Location" for graphics that show the location of the sensor's on the in-line engines and on the vee engines.5 Volt Power SupplyThe Electronic Control Module (ECM) supplies 5.0 0.5 VDC to these sensors:
Filtered engine oil pressure
Crankcase pressure
Inlet air temperature
Fuel temperature
Engine oil temperature
Unfiltered engine oil pressure
Desired speed potentiometerThe ECM can be configured for one of these types of speed control:
0 to 5 V potentiometer
4 to 20 mAThe desired speed potentiometer (if equipped) must be supplied with +5 VDC from the ECM. If the desired speed potentiometer has a short circuit or the potentiometer's wiring has a short circuit, a 262-03 or 262-04 diagnostic code may be activated. There are no diagnostic codes for the circuit of the desired speed potentiometer.
Illustration 1 g01442989
Control Panel (if equipped)
(1) Desired speed potentiometer The internal circuits for J2-2 (sensor supply) and J2-18 (speed control supply) are wired to the same voltage source inside the ECM. A short circuit on one of these terminals will cause a short circuit on the other terminal. A 262-4 5 Volt Sensor DC Power Supply voltage below normal will be activated if the following conditions occur:
The desired speed signal wire is shorted to ground.
The speed control potentiometer is near the maximum desired speed or at the maximum desired speed.A diagnostic code for the 5 volt power supply is probably caused by a short circuit or by an open circuit in a harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.
Illustration 2 g01442990
Terminal Box
(2) ECM connector J2/P2
(3) ECM connector J1/P1
(4) 16 amp circuit breaker
(5) Connectors J3/P3 for the customer's connector
(6) Connectors J4/P4 for the optional control panel (if equipped) or for a customer's connector
(7) J5/P5 connectors for the harness from the sensors
(8) J6/P6 connectors for the harness from the sensors 8 Volt Power SupplyThe ECM supplies 8.0 0.8 VDC to these sensors:
Engine coolant pressure sensor
All of the detonation sensorsThe internal circuits for J2-56, J2-57 and J2-65 are wired to the same voltage source inside the ECM. A short circuit on one of these terminals will cause a short circuit on the other terminals.A diagnostic code for the 8 volt sensor supply is probably caused by a short circuit or by an open circuit in a harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the engine control switch to the OFF/RESET position. Switch the 16 amp circuit breaker for the ECM OFF.
Thoroughly inspect the condition of the connectors that are for the sensors. Inspect the condition of connectors that are located at the terminal box for the ECM. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in each of the circuits.
Check the torque of the allen head screws for each of the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from the sensors to the appropriate connector on the terminal box. Expected Result:All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points. All of the sensors are properly installed.Results:
OK - All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points. The components are in good condition with proper connections. Proceed to Test Step 2.
Not OK - At least one of the connectors, pins, and sockets are not connected properly. At least one of the connectors and/or the wiring has corrosion, abrasion, and/or pinch points.Repair: Perform the necessary repairs and/or replace parts, if necessary.STOPTest Step 2. Check for Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Switch the 16 amp circuit breaker for the ECM ON. Turn the engine control switch to the STOP position.
Use the "Active Diagnostic" screen on Cat ET. Check for the following active diagnostic codes:
41-3 8 Volt DC Supply short to +batt
41-4 8 Volt DC Supply short to ground
262-3 5 Volt Sensor DC Power Supply voltage above normal
262-4 5 Volt Sensor DC Power Supply voltage below normalNote: Monitor the active diagnostic code and the logged diagnostic codes on Cat ET. Wait at least 30 seconds in order for diagnostic codes to become active.
Adjust the potentiometer from the maximum speed setting to the minimum speed setting while you check for active diagnostic codes. Ensure that the adjustment of the speed potentiometer is not the cause of the active diagnostic code. Expected Result:None of the diagnostic codes that are listed above are active.Results:
OK - None of the diagnostic codes for the sensor supply are active at this time. Repair: Use the "Logged Diagnostic" screen on Cat ET to check for logged codes. Look for the same codes that are listed above. If any of the above codes are logged and the engine is running properly, there may be an intermittent electrical problem in a connector or on a wiring harness. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for troubleshooting information.STOP
Active 262-3 or 262-4 Code - A 262-3 or 262-4 diagnostic code is active at this time. There is a problem with one of the