0379968 JOHNSON ARMATURE ASSEMBLY

Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
3266-3 Water Pump Module Supply Input: Voltage Above Normal The voltage to the EWPC is above the acceptable value. The code is logged.
3266-4 Water Pump Module Supply Input: Voltage Below Normal The voltage to the EWPC is below the acceptable value.
The Power Train Electric Drive System and the Accessory Power System will contain hazardous voltage levels during machine operation and for a period of time after machine shutdown.Do not remove any covers that will expose energized electrical components while the engine is operating. Do not remove any covers that will expose the energized electrical components while the components remain energized following an engine shutdown.Do not perform any type of electrical maintenance on the orange hazardous voltage conductors, the power train components or the accessory power system components while the engine is operating.Do not perform any type of electrical maintenance on the orange hazardous voltage conductors, the power train components or the accessory power system components while the components remain energized following an engine shutdown.Always perform the safe shutdown and de-energizing procedure before performing electrical service on the Power Train Electric Drive System or the Accessory Power System.Failure to follow these instructions could result in personal injury or death.
In order to avoid the build up of hazardous live voltages on the exposed surfaces, all grounding wires must be properly connected at all times during engine operation.Any disconnected grounding wires (including the grounding bond wires, the conductor shield wires, the power inverter grounding straps and the component housing grounding straps) must be properly reconnected before the engine is started.Failure to follow these instructions could result in personal injury or death.
Note: Always perform the procedure for safe shutdown and de-energizing before performing electrical service on the Power Train Electric Drive System or the "Accessory Power System". This procedure must be performed in order to verify that the voltage in the power train electrical system has been discharged to less than 50.0 VDC. Refer to the Specifications, Systems Operation, Troubleshooting, Testing and Adjusting, "Electrical Maintenance Guidlines" for the proper procedure.Note: A multimeter must be used to verify that there is little or no voltage present at the exposed conductors before any other action is taken. The voltage must be manually measured in order to confirm it to be at a low level (50.0 VDC or less).Test Step 1. DETERMINE THE DIAGNOSTIC CODE
Establish communication between the Caterpillar Electric Technician (ET) and the Electronic Control Module (ECM) . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
Determine the diagnostic code that is active. Note: Check for machine codes that pertain to the circuit for the water pump control. Troubleshoot any codes before proceeding with this procedure.Results:
A 3266-3 code is active. - Proceed to Test Step 2.
A 3266-4 code is active. - Proceed to Test Step 3.Test Step 2. HIGH SUPPLY VOLTAGE AT THE EWPC
Illustration 1 g02029396
Accessory Power Converter (APC) and the external connections
(1) System voltage circuit for ground wire connection
(2) System voltage and battery charging circuit for +battery
(3) 650 volt DC power bus from the power inverter
(4) Connector in low voltage circuit for system control
(5) 320 VDC accessory power bus to the water pump motor
(6) 320 VDC accessory power bus to the HVAC compressor
Illustration 2 g02029401
EWPC at the rear of the engine compartment on the upper right side
(7) EWPC
(8) 320 VDC accessory power bus supply from the APC
(9) Four conductor, three-phase, AC supply conductor cable to the electric water pump
(10) System power and control circuit connector
While the engine is running, use the monitoring system to check the following voltage readings:
Accessory Bus Voltage
EWPC Bus VoltageResults:
The Accessory Bus Voltage is high. - Repair: Always perform the procedure for safe shutdown and de-energizing before performing electrical service on the Power Train Electric Drive System or the Accessory Power System. Refer to the Specifications, Systems Operation, Troubleshooting, Testing and Adjusting, "Electrical Maintenance Guidlines" for the proper procedure.A multimeter must be used to verify that there is little or no voltage present at the exposed conductors before any other action is taken. Once the voltage is manually measured and confirmed to be at a low level (50.0 VDC or less), proceed with this procedure.Contact the Caterpillar Dealer Solution Network (DSN).STOP
The EWPC Bus Voltage is high. - Repair: Always perform the procedure for safe shutdown and de-energizing before performing electrical service on the Power Train Electric Drive System or the Accessory Power System. Refer to the Specifications, Systems Operation, Troubleshooting, Testing and Adjusting, "Electrical Maintenance Guidlines" for the proper procedure.A multimeter must be used to verify that there is little or no voltage present at the exposed conductors before any other action is taken. Once the voltage is manually measured and confirmed to be at a low level (50.0 VDC or less), proceed with this procedure.Contact the Caterpillar Dealer Solution Network (DSN).STOPTest Step 3. CHECK FOR AN OPEN CIRCUIT
While the engine is running, use the monitoring system to check the following voltage readings:
Accessory Bus Voltage
EWPC Bus VoltageResults:
The EWPC Bus Voltage is more than 75V less than the Accessory Bus Voltage. - Repair: Always perform the procedure for safe shutdown and de-energizing before performing electrical service on the Power Train Electric Drive System or the Accessory Power System. Refer to the Specifications, Systems Operation, Troubleshooting, Testing and Adjusting, "Electrical Maintenance Guidlines" for the proper procedure.Perform the following procedure.
Disconnect both connectors on the harness between the EWPC and the APC.
Check the continuity for each wire in the harness.
Visually check the harness for damage. If necessary, replace the harness.
Connect the harness. Verify that both connectors are clean, dry and tight. Refer to the Specifications, Systems Operation, Troubleshooting, Testing and Adjusting, "Accessory Power System" for additional information.Verify that the problem is resolved.If the problem is not resolved contact the Caterpillar Dealer Solution Network (DSN).STOP