Buick Regal: Cooling Fan Inoperative (LTG)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Circuit/System Description
The engine cooling fan system is composed of one electric cooling fan and a
cooling fan control module.
The engine control module (ECM) controls the fan speed by sending a pulse width
modulated (PWM)
signal to the cooling fan control module. The cooling fan control module varies
the voltage drop across the
cooling fan motor in relation to the pulse width modulated signal, which enables
cooling fan operation at
variable speeds. The ECM will only operate the cooling fan at certain
percentages to prevent undesirable
noise and vibration. The cooling fan control module is thermally protected to
prevent module damage in
the case of a short circuit condition in the cooling fan motor.
Diagnostic Aids
- The cooling fan will not operate when the scan tool Cooling Fan Motor
Command parameter
displays less than 4 %. This is a normal condition.
- A delay or ramp up of approximately 12 seconds may occur before the
cooling fan activates or
changes speed when being commanded with a scan tool.
- The cooling fan Control Function operates as described below when the
ignition is ON, and engine is
OFF:
- Command State 1 operates the cooling fan at approximately 18 %
- Command State 2 operates the cooling fan at approximately 54 %
- Command State 3 operates the cooling fan at approximately 67 %
- Command State 4 operates the cooling fan at approximately 85 %
- Command State 5 operates the cooling fan at approximately 90 %
- During normal operating conditions the ECM may initially activate the
cooling fan at 4 or 5 % and
then increase to the percentages indicated above, as needed, to satisfy
powertrain cooling
requirements. Generally, the ECM will operate the cooling fan at the
specified percentages but, may
scale the percentages either higher or lower in response to generator
demand.
- When operating the cooling fan with a scan tool, the Commanded States 1
- 5 should be exercised in
order, from OFF to High or High to OFF. The cooling fan control module may
disable the cooling
fan if a Commanded State is skipped.
Reference Information
Schematic Reference
Engine Heating/Cooling Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify that DTC P0480, P0691, or P0692, is not set.
Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG) or DTC
P0480, P0481,
P0691, P0692, P0693, or P0694 (LGX).
- Go to next step: If no DTC is set.
NOTE: A slight delay may occur before the cooling fan activates.
3. Verify the G10 Cooling Fan Motor activates and increases in speed with
each command using a scan
tool.
- The cooling fan does not activate or increase in speed
Refer to Circuit/System Testing
- Go to next step: The cooling fan activates and increases in speed
4. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector G10 Cooling Fan Motor.
2. Verify that a test lamp illuminates between the ground circuit terminal 2 and
B+.
- If the test lamp does not illuminate
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes
for all vehicle systems
to power down.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If the test lamp illuminates
3. Test or replace the G10 Cooling Fan Motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic
procedure.
- Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan
Replacement (3.6L LGX)
for G10 Cooling Fan Motor replacement.
- Control Module References
ENGINE OVERHEATING
DEFINITION: Either of the
following conditions indicate a probable engine overheat condition. The engine
temperature gauge is in the red (overheat) zone and/or the engine temperature
indicator is ON. Hot engine coolant overflows from the coolant recovery
reservoir and/or radiator cap onto the ground while the engine is running.
LOSS OF COOLANT
THERMOSTAT DIAGNOSIS
COOLANT HEATER INOPERATIVE
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
Circuit/System Description
The coolant heater is a 300 watt heating element that mounts to the engine
block. The coolant heater
operates using 120 V AC external power and is designed to warm the coolant in
the engine block area for
improved starting in very cold weather. The coolant heater also helps reduce
fuel consumption when a cold
engine is warming up. The unit is equipped with a detachable AC power cord.
There is an internal thermal
switch in the coolant heater cord that prevents operation above -18ºC (0ºF). A
weather shield on the
cord is provided to protect the plug when not in use.
Reference Information
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Circuit/System Testing
NOTE: The coolant heater cord will read Open due to an internal thermal
switch if
the ambient temperature is above -18ºC (0ºF).
1. Ignition OFF, disconnect the coolant heater cord from the E19 Coolant
Heater.
2. Test for 40 - 55 Ω between the terminals of the E19 Coolant Heater.
Replace the E19 Coolant Heater.
- Go to next step: If within 40 - 55 Ω
3. Test for infinite resistance between each terminal of the E19 Coolant
Heater and ground.
- If less than infinite resistance
Replace the E19 Coolant Heater.
- Go to next step: If infinite resistance
4. Test for less than 2 Ω between the engine coolant heater cord plug and the
engine coolant heater cord
connector for each circuit.
Replace the engine coolant heater cord.
- Go to next step: If less than 2 Ω
Go to next step: All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic
repair.
ENGINE FAILS TO REACH NORMAL OPERATING TEMPERATURE
READ NEXT:
Special Tools
GE-42401-A Radiator Cap and Surge Tank Test Adapter
For equivalent regional tools, refer to Special Tools.
WARNING: To avoid being burned, do not remove the radiator cap or surge
tank
c
Special Tools
GE-42401-A Radiator Cap and Surge Tank Test Adapter
For equivalent regional tools, refer to Special Tools.
WARNING: Under pressure, the temperature of the solution in the
radiator can b
SEE MORE:
Special Tools
J-42572 Drive Shaft Seal Clamp Pliers
Disassembly Procedure
1. Front Wheel Drive Half Shaft - Remove.
Front Wheel Drive Half Shaft Replacement - Left Side
Front Wheel Drive Half Shaft Replacement - Right Side (AWD)Front
Wheel Drive Half Shaft
Replacement - Right Side (FWD)
2. Pl
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
D