Buick Regal: DTC B269A, B269C, or B269D
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 Descriptor
DTC B269A
Heater Coolant Pump Control Circuit
DTC B269C
Heater Coolant Pump Control Circuit Low Voltage
DTC B269D
Heater Coolant Pump Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The primary purpose of the heater core coolant pump is to circulate engine
coolant through the HVAC
heater core when heat is required in the cabin for comfort. This normally
happens when the vehicle is in
an Auto Stop and the mechanical pump is not spinning. If the HVAC control module
has determined
heat is needed for the cabin, a request is sent via serial data to the engine
control module to turn the
pump ON. The engine control module controls the auxiliary coolant pump relay via
the heater core
coolant pump relay control circuit. The heater core coolant pump relay supplies
voltage to the heater
core coolant pump.
Conditions for Running the DTC
- The 12 V battery voltage is greater than or equal to 9 V.
- The auxiliary heater coolant pump enable is commanded.
Conditions for Setting the DTC
The engine control module detects the auxiliary heater coolant pump relay
control circuit is open,
shorted to voltage or shorted to ground.
Action Taken When the DTC Sets
DTCs B269A, B269C, and B269D are type B DTCs.
Conditions for Clearing the DTC
DTCs B269A, B269C, and B269D are type B DTCs.
Reference Information
Schematic Reference
HVAC Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Automatic HVAC 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 Testing
1. Ignition OFF, disconnect the X4 harness connector at the X50A Fuse Block -
Underhood.
2. Connect a test lamp between the control circuit terminal C4 and B+, ignition
ON.
3. Verify the test lamp turns ON and OFF when commanding the G36 Auxiliary
Heater Coolant
Pump On and Off with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the K20 Engine
Control Module, ignition ON.
- Test for less than 1 V between the control circuit 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.
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the harness connector at
the K20 Engine
Control Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the K20 Engine Control Module.
- Go to next step: If the test lamp turns ON and OFF
4. Ignition OFF and all vehicle systems OFF, connect the X4 harness connector
at the X50A Fuse
Block - Underhood. Disconnect the harness connector at the G36 Auxiliary Heater
Coolant Pump.
It may take up to 2 min for all vehicle systems to power down.
5. Test for less than 10 Ω between the ground circuit terminal 1 and ground.
- Ignition OFF.
- 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 less than 10 Ω
6. Connect a test lamp between the control circuit terminal 2 and ground.
7. Verify the test lamp turns ON and OFF when commanding the G36 Auxiliary
Heater Coolant
Pump ON and OFF with a scan tool.
- If the test lamp is always OFF and the circuit fuse is good
- Ignition OFF, remove the test lamp, disconnect the X4 harness connector
at the X50A Fuse
Block - Underhood.
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the X50A Fuse Block - Underhood.
- If the test lamp is always OFF and the circuit fuse is open
- Ignition OFF, remove the test lamp.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, test or replace the G36 Auxiliary Heater
Coolant Pump.
- If the test lamp is always ON
- Ignition OFF, disconnect the X4 harness connector at the X50A Fuse Block
- Underhood,
ignition ON.
- Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the X50A Fuse Block - Underhood.
- Go to next step: If the test lamp turns ON and OFF
8. Test or replace the G36 Auxiliary Heater Coolant Pump.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- HVAC Component Replacement Reference
- Control Module References for control module replacement, programming
and setup
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
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:
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if
provided), should be checked
m
Reporting Safety Defects to
the United States
Government
If you believe that your vehicle
has a defect which could cause
a crash or could cause injury or
death, you should immediately
inform the National Highway
Traffic Safety Administration
(NHTSA) in addition to notifying
General Motors.
If NHTSA