34310-ZV5-821 Honda CONTROL UNIT, TRIM (Honda Code 3703923).

Table 1
J1939 Code and Description CDL Code and Description Comments
N/A E563 (3)
Low Engine Coolant Flow The ECM detects that the coolant flow through the engine is lower than expected.
N/A 1937-2
Engine Coolant Flow Switch : Erratic, Intermittent, or Incorrect The ECM detects that the coolant flow through the engine is different than expected.
109-17
Engine Coolant Pressure : Low - least severe (1) E2112 (1)
Low Engine Coolant Pressure The engine coolant pressure is lower than expected for an extended period. The code is logged.
109-18
Engine Coolant Pressure : Low - moderate severity (2) E2112 (2)
Low Engine Coolant Pressure The engine coolant pressure is lower than expected for an extended period. The code is logged.
109-1
Engine Coolant Pressure : Low - most severe (3) E2112 (3)
Low Engine Coolant Pressure The engine coolant pressure is lower than expected for an extended period. The code is logged.
Table 2
Troubleshooting Test Steps Values Results
1. Verify the Coolant Level
A. Verify that the coolant is filled to the correct level. If the coolant level is too low, air will get into the cooling system. Air in the cooling system will cause a reduction in coolant flow and pressure.
B. Check the cooling system for coolant leaks.
Coolant Level
Result: The coolant level is correct.
Proceed to Test Step 2.
Result: The coolant level is not correct.
Repair: Determine the cause of the low coolant level. Refer to Troubleshooting, "Coolant Level Is Low". Verify that the problem has been corrected.
2. Check the Cooling System Hose Routing
A. Check the cooling system clamps and hoses to make sure that the components are installed in the proper location and the clamps are tight.
B. Ensure that there are no kinks or tight bends that may cause excessive restriction.
C. Check to make sure that the hoses are routed correctly.
Leaks or Kinks
Result: The coolant clamps and hoses are installed properly.
Proceed to Test Step 3.
Result: The coolant clamps and hoses are not installed properly.
Repair: Repair or replace the damaged cooling system component. Verify that the problem has been corrected. Return the unit to service.
3. Check the Expansion Tank (if equipped)
A. Check the shunt line for a restriction. A restriction of the shunt line from the expansion tank to the inlet of the jacket water pump will cause a reduction of water pump efficiency.
B. Inspect the expansion tank for a restriction that blocks the port to the shunt line.
Note: The expansion tank may be integrated into the design of the radiator top tank and may not be separate.
Shunt Line
Result: The shunt line is properly installed and there are no restrictions.
For a E2112 or 109 code, proceed to Test Step 4.
For a E563 or 1937 code, proceed to Test Step 5.
Result: The shunt line is not properly installed or there are restrictions.
Repair: Install the shunt line correctly or replace the line if necessary. Remove any restrictions that are found.
Verify that the problem has been corrected. Return the unit to service.
4. Check the Coolant Pressure Sensor For Accuracy
A. Install a mechanical pressure gauge in the coolant jacket near the coolant pressure sensor.
B. Start the engine.
C. Connect to the engine ECM using Cat® Electronic Technician (ET).
D. Allow the engine to run and record the pressure on the mechanical gauge.
E. Check the pressure reading at various engine speeds.
Coolant Pressure Sensor
Result: The pressure difference between the mechanical gauge and the reading in Cat ET is less than 14 kPa (2 psi).
Proceed to Test Step 6.
Result: The pressure difference between the mechanical gauge and the reading in Cat ET is greater than 14 kPa (2 psi).
Repair: Replace the coolant pressure sensor.
Verify that the problem has been corrected. Return the unit to service.
5. Check the Coolant Flow Switch
A. Remove the coolant flow switch from the engine.
B. Turn the keyswitch to ON.
C. Connect to the engine ECM using Cat ET.
D. Rotate the paddle on the end of the coolant flow switch.
E. Monitor the status of the coolant flow switch in Cat ET.
Coolant Flow Switch
Result: The coolant flow switch status changed in Cat ET when the paddle was rotated.
Proceed to Test Step 6.
Result: The coolant flow switch status did not change in Cat ET when the paddle was rotated.
A failed coolant flow switch has been detected.
Repair: Replace the coolant flow switch.
Verify that the problem has been corrected. Return the unit to service.
6. Check the Water Pump
A. Remove the water pump and check for a damaged or loose impeller, or a restriction in the water pump inlet or outlet ports.
Damaged Impeller
Result: The water pump impeller is not damaged or loose and there are no restrictions.
Proceed to Test Step 7.
Result: The water pump impeller is damaged or loose, or there are restrictions.
Repair: Replace the water pump.
Verify that the problem has been corrected. Return the unit to service.
7. Check the Radiator or Heat Exchanger
A. Check the radiator or heat exchanger for a restriction. Check internally for dirt, debris, or deposits on the radiator core.
Restrictions
Result: There were deposits or restrictions in the radiator or heat exchanger.
Repair: Clean or replace the radiator or heat exchanger.
Verify that the problem has been corrected. Return the unit to service.
Result: There were no deposits or restrictions in the radiator or heat exchanger.
Proceed to Test Step 8.
8. Check the Oil Cooler
A. Check the inlet side of the oil cooler for debris or blockage.
Restrictions
Result: There was debris or restrictions in the oil cooler.
Repair: Clean or replace the oil cooler.
Verify that the problem has been corrected. Return the unit to service.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).