PANEL AS-CAB 2623884 - Caterpillar

Table 1
Diagnostic Codes for Cooling Fan Control
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
4212-5 291-5 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.
4212-6 291-6 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 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 motor by allowing oil to bypass the fan motor. The fan pump drives the fan. When the ECM outputs minimum current to the engine fan control solenoid, less oil is bypassed. The fan motor 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 motor 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 in the