850685 1 Mercury GROMMET

Table 1
J1939 Code and Description CDL Code and Description Comments
4212-5
Fan Drive Bypass Command Status : Current Below Normal 291-5
Engine Cooling Fan Solenoid : Current Below Normal The Electronic Control Module (ECM) detects an open circuit in the circuit for the engine fan control solenoid.
The ECM sends minimum current to the fan control solenoid.
The code is logged.
4212-6
Fan Drive Bypass Command Status : Current Above Normal 291-6
Engine Cooling Fan Solenoid : Current Above Normal The ECM detects a short circuit to ground in the circuit for the engine fan control solenoid.
The ECM sends minimum current to the fan control solenoid.
The code is logged. The Electronic Control Module (ECM) monitors engine coolant temperature, intake manifold air temperature, and hydraulic oil temperature. The ECM monitors the sensors to determine the correct speed for the engine cooling fan.The ECM controls the speed of the fan by controlling the current to the engine fan control solenoid. The engine fan control solenoid controls the amount of pressure to the fan pump by allowing oil to bypass the fan pump. The fan pump drives the fan. When the ECM outputs minimum current to the engine fan control solenoid, less oil is bypassed. The fan pump will now drive the fan at a higher rpm. When the ECM outputs maximum current to the engine fan control solenoid, more oil is bypassed. The fan pump will now drive the fan at a lower rpm.If the ECM detects a system fault, the ECM provides minimum current to the solenoid. Minimum current ensures a maximum fan speed while the fault condition exists.An override is available with Cat® Electronic Technician (ET). An override allows the fan to be manually changed from the minimum to the maximum rpm.
Illustration 1 g06553129
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -6 code is active or logged.
Proceed to Test Step 2.
Result: A -5 code is active or logged.
Proceed to Test Step 3.
2. Check the Wiring for an Open Circuit
A. Remove the electrical power from the ECM.
B. Disconnect the connector for the engine fan control solenoid.
C. Restore the electrical power to the ECM.
D. Connect Cat ET.
E. Use Cat ET to perform the following test:
- "Fan Override"
E. Use Cat ET to monitor the following:
- Codes
F. Record any active codes.
H. Disable the "Fan Override".
Create a Short
Result: A -6 code remains active. There is a short circuit between the harness connector for the engine fan control solenoid and the ECM.
Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled.
Verify that the repair eliminated the problem.
Result: A -6 code was active before disconnecting the connector. A -5 code became active after disconnecting the connector.
Repair: Replace the engine fan control solenoid.
Verify that the repair eliminated the problem.
3. Check the Wiring for a Short Circuit
A. Remove the electrical power from the ECM.
B. Fabricate a jumper wire that is long enough to create a short between the terminals of the connector for the engine fan control solenoid. Crimp connector pins to each end of the jumper wire.
C. Install the jumper wire between the following terminals on the wiring harness side of the connector:
- Terminal 1 (engine fan control solenoid) and Terminal 2 (solenoid return)
D. Restore the electrical power to the ECM.
E. Connect Cat ET.
F. Use Cat ET to perform the following test:
- "Fan Override"
G. Use Cat ET to monitor the following:
- Codes
H. Record any active codes.
J. Disable the "Fan Override".
K. Remove the jumper wire.
Create an Open
Result: The -5 code remains active with the jumper in place.
Repair: Repair or replace the connectors or wiring. Ensure that all the seals are properly in place and ensure that the connectors are coupled.
Verify that the repair eliminated the problem.
Result: A -6 code became active when the jumper wire is installed. A -5 code becomes active when the jumper wire is removed.
Repair: Replace the engine fan control solenoid.
Verify that the repair eliminated the problem.
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).