Buick Regal: DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX)
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 Output Circuit
DTC P0691
Cooling Fan Speed Output Circuit Low Voltage
DTC P0692
Cooling Fan Speed Output Circuit High Voltage
Diagnostic Fault Information
- Opens left cooling fan fuse without a DTC.
- Left fan inoperative without a DTC.
- Opens right cooling fan fuse without a DTC.
- Right cooling fan inoperative without a DTC.
Circuit/System Description
The engine control module (ECM) commands the speed of the cooling fans based
on cooling requirements.
The ECM controls the cooling fan speed by commanding the cooling fan control
modules. Each cooling
fan control module is supplied power through its own fused power circuit. Each
cooling fan control module
is supplied ground though its own ground circuit. The ECM sends a pulse width
modulated (PWM) signal
to the cooling fan control module. The cooling fan control module interprets the
signal and operates the
cooling fans at the commanded speeds.
Conditions for Running the DTC
- The ignition voltage is 11 volts or greater.
- The engine speed is 400 RPM or greater.
- The ECM driver transitions from ON to OFF or from OFF to ON.
- DTCs P0480, P0691, and P0692 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.
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
K20 Engine Control Module: Scan Tool Information for scan tool
information
Circuit/System Verification
NOTE: There is a slight delay before the cooling fans activate.
1. Engine operating, command the Cooling Fans from 0 % to 90 % with a scan
tool.
2. Verify the G10 Cooling Fan Motors activates in each available speed.
- 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. 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
NOTE: Both cooling fan motors must be disconnected or incorrect
diagnosis
may result.
1. Ignition OFF, disconnect the following G10 Cooling Fan Motors.
- G10L Cooling Fan Motor Left.
- G10R Cooling Fan Motor Right.
2. Ignition ON, verify that a test lamp illuminates between the following
terminals and ground.
- G10L Cooling Fan Motor Left - terminal 1
- G10R Cooling Fan Motor Right - terminal 1
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the test lamp and turn 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 appropriate 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, remove the test lamp and turn all vehicle systems OFF. It
may take up to 2
minutes for all vehicle systems to power down.
- Test for infinite resistance between the terminals listed below and
ground.
- G10L Cooling Fan Motor Left - terminal 1
- G10R Cooling Fan Motor Right - terminal 1
- If less than infinite resistance, repair the short to ground in the
circuit.
- If infinite resistance, replace the appropriate 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, 3 - 4 volts on the output circuit is normal.
3. Ignition OFF, disconnect the following G10 Cooling Fan Motors.
- G10L Cooling Fan Motor Left
- G10R Cooling Fan Motor Right
4. Connect a DMM, set on the diode setting, between the following terminals
and ground.
- G10L Cooling Fan Motor Left - terminal 4
- G10R Cooling Fan Motor Right - terminal 4
5. Ignition ON, verify the DMM reading is greater than 2.5 V or displays O.L.
with the cooling fan
commanded OFF.
- Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for
all vehicle systems to
power down.
- Disconnect the K20 Engine Control Module harness connector X1.
- Test for infinite resistance between the appropriate 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.
6. Command the Cooling Fan ON to 90 % with a scan tool.
7. Verify the DMM reading is less than 1 V.
- Ignition OFF, disconnect harness connector X1 at the K20 Engine Control
Module, ignition
ON.
- Test for less than 1 V between the appropriate 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 G10 Cooling Fan Motor control circuit
terminal 4, end to end.
- If 2 Ω or greater, repair the open/high resistance in the control
circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: If less than 1 V
8. Test or replace the appropriate 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 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
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
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
SEE MORE:
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.
Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descripto
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.
Diagnostic Fault