Buick Regal: DTC P0480, P0481, P0691, P0692, P0693, or P0694 (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.
DTC Descriptors
DTC P0480
Cooling Fan Speed Control Circuit
DTC P0691
Cooling Fan Speed Output Circuit Low Voltage
DTC P0692
Cooling Fan Speed Output Circuit High Voltage
Diagnostic Fault Information
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.
Conditions for Running the DTC
- The ignition voltage is greater than 11 volts.
- The DTCs run continuously once the above conditions are met.
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the actual state
of the control circuit do not
match for greater than 5 seconds.
Action Taken When the DTC Sets
DTCs P0480, P0691, and P0692 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0480, P0691, and P0692 are Type B DTCs.
Diagnostic Aids
- 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.
- In order to set certain DTCs the PCM must command the Cooling Fan system
On. Using the scan
tool to operate the Cooling Fan will not set certain DTCs. In these cases
run the vehicle until it
reaches an appropriate condition for the PCM to command the Cooling Fans On.
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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
NOTE: A slight delay may occur before the cooling fan activates.
2. Verify the G10 Cooling Fan Motor activates in each available speed when
commanding the cooling
fan ON with a scan tool. The cooling fan speed should increase with each
command.
- The cooling fan does not activate or increase in speed as commanded
Refer to Circuit/System Testing
- Go to next step: The cooling fan activates and increases in speed as
commanded
3. Operate the vehicle within the Conditions for Running the DTC to verify
the DTC does not reset.
You may also operate the vehicle within the conditions that you observed from
the Freeze
Frame/Failure Records data.
4. Verify the DTC does not set.
Refer to Circuit/System Testing
- Go to next step: If the DTC does not set
5. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan
Motor.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit
terminal 1 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- 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 B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage
at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes
for all vehicle systems
to power down.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground in the
circuit.
- If infinite resistance, replace the G10 Cooling Fan Motor.
- Go to next step: If the test lamp illuminates
NOTE: The cooling fan speed output circuit is pulled-up to a voltage
within
the ECM, 2-3 volts on the output circuit is normal.
3. Connect a DMM, set on the diode setting, between the G10 Cooling Fan Motor
control circuit
terminal 4 and ground.
4. Verify the DMM reading is greater than 2.5 V or displays O.L. with the
cooling fan commanded
OFF.
- Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes
for all vehicle systems
to power down.
- Disconnect the harness connector X1 at the K20 Engine Control Module.
- Test for infinite resistance between the G10 Cooling Fan Motor control
circuit terminal 4 and
ground.
- If less than infinite resistance, repair the short to ground in the
circuit.
- If infinite resistance, replace the K20 Engine Control Module.
- Go to next step: If greater than 2.5 V or displays O.L.
5. Command the cooling fan ON to 90% with a scan tool.
6. Verify the DMM reading is less than 1 V.
- Ignition OFF.
- Disconnect the harness connector X1 at the K20 Engine Control Module,
ignition ON.
- Test for less than 1 V between the G10 Cooling Fan Motor control circuit
terminal 4 and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V.
- 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 circuit end to end.
- If 2 Ω or greater, repair the open in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: If less than 1 V
7. Replace the K20 Cooling Fan Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan
Replacement (3.6L LGX)
for G10 Cooling Fan Motor.
- Control Module References for ECM replacement, setup, and programming
READ NEXT:
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.
Diag
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.
Diag
Important Preliminary Inspections Before Starting
Before using the Symptom diagnosis, perform the following:
Perform Diagnostic System Check - Vehicle and verify all of the
following items:
Engi
SEE MORE:
Removal Procedure
1. Raise and support the vehicle. Lifting and Jacking the Vehicle.
2.
Transmission Vent Hose (1) @Transmission - Disconnect.
3. Lower the vehicle.
4.
Unclip the vent hose retainer (2) from the radiator surge tank (3).
NOTE: Note the routing of the vent hose.
5. Transmission Ve
Preliminary Procedures
1. Raise and support the vehicle. Lifting and Jacking the Vehicle.
2. Place a drain pan under the drain cock.
Radiator Drain Cock
Procedure
Fill the cooling system to the proper level.
Start the engine and check for coolant leaks.
RADIATOR REPLACEMENT (2.0L LT