0331231 JOHNSON SEAL, Rear lower

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.
N/A 5325-5
Engine Cooling Fan Directional Solenoid : Current Below Normal The ECM detects an open circuit for the engine fan control solenoid. The ECM sends a minimum current to the fan control solenoid. The code is logged.
N/A 5325-6
Engine Cooling Fan Directional Solenoid : Current Above Normal The ECM detects a short circuit for the engine fan control solenoid. The ECM sends a minimum current to the fan control solenoid. The code is logged. The 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.Conventional 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.Bidirectional Fan
The ECM controls the speed and direction of the fan by directly controlling the current to the engine fan control solenoid in the fan motor. As current is applied to the solenoid, the forward fan speed decreases until an intermediate current commands the fan to stop (zero speed). As the current continues to increase to the solenoid, the direction of the fan reverses and the speed continues to increase.If the ECM detects a system fault, the ECM provides a minimum current to the solenoid. The minimum current ensures a maximum fan speed while the fault condition exists.An override is not available with Cat ET for the bidirectional fan. To troubleshoot this system, turn the key on with the engine off, which will apply the minimum current to the solenoid.Recommend Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the keyswitch to OFF.
B. Verify that the solenoid connector is free of debris and connected securely.
C. Connect Cat ET to the service tool connector.
D. Turn the keyswitch to ON.
E. Select diagnostic tests from Cat ET. Select the "Override Parameters" screen on Cat ET.
Note:An override is not available with Cat ET for the bidirectional fan. To troubleshoot this system, turn the key on with the engine off, which will apply the minimum current to the solenoid. Then wait 30 seconds or longer for the code to become active
F. Activate the fan override.
G. Monitor the active code screen on Cat ET