Cutlass Ciera V6-3100 3.1L MFI VIN M (1994)
A/C Signal: Description and Operation
Cooling Fan Control
Relay Center
DESCRIPTION
This vehicle utilizes two electric cooling fans for engine and A/C condenser cooling.
OPERATION
The engine is equipped with two Powertrain Control Module (PCM) controlled electric cooling fan(s). The secondary fan (# 2) or auxiliary
cooling fan is used for heavy duty cooling with A/C.
When the engine is running, the PCM will turn "ON" the primary cooling fan (# 1) for any one of the following reasons:
^
Diagnostic Trouble Code (DTC) P0117, P0118 or P153O is set.
^
Engine coolant temperature is 106°C (223°F) or greater.
^
A/C is requested and vehicle speed is less than 50mph.
^
A/C refrigerant pressure is 190 psi or greater with A/C requested.
Once the primary cooling fan (# 1) is enabled, the PCM will turn the primary cooling fan (# 1 ) "OFF" when:
^
Engine is turned "OFF."
^
Engine coolant temperature drops to 102°C (216°F) or less.
^
A/C refrigerant pressure drops to 140 psi or less with A/C requested.
When the engine is running the PCM will turn "ON" the secondary cooling fan (auxiliary # 2) for any one of the following reasons:
^
Engine Coolant Temperature (ECT) is 112°C (233°F) or greater.
^
A/C is requested and vehicle speed is less than 50mph.
^
A/C refrigerant pressure is 246 psi or greater.
Once the secondary cooling fan (auxiliary # 2) is enabled, the PCM will turn the secondary cooling fan (# 2) "OFF" when:
^
Engine is turned "OFF"
^
When the Engine Coolant Temperature (ECT) sensor indicates the coolant temperature has dropped to 108°C (226°F) or less.
^
When the A/C refrigerant pressure drops to 196 psi or below.
