Buick Regal: DTC P0449, P0498, or P0499
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 P0449
Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit
DTC P0498
Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit Low Voltage
DTC P0499
Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The evaporative emission (EVAP) vent solenoid valve is a normally open valve.
Battery voltage is
supplied to the EVAP vent solenoid valve through a fuse. The engine control
module (ECM) grounds the
EVAP vent solenoid valve control circuit through an internal switch called a
driver. The evaporative
emission (EVAP) vent solenoid valve is a normally open valve. Battery voltage is
supplied to the EVAP
vent solenoid valve through a fuse. A scan tool will display the commanded state
of the EVAP vent
solenoid valve as ON (Not Venting) or OFF (Venting).
Conditions for Running the DTC
- The system voltage is greater than 11 V.
- The DTCs run continuously once the above conditions are met.
Conditions for Setting the DTC
P0449
The ECM detects the EVAP Vent Solenoid Valve control circuit is open for
greater than 0.25 s.
P0498
The ECM detects the EVAP Vent Solenoid Valve control circuit is shorted to
ground for greater than
0.25 s.
P0499
The ECM detects the EVAP Vent Solenoid Valve control circuit is shorted to
voltage for greater than
0.25 s.
Action Taken When the DTC Sets
DTC P0449, P0498 and P0499 are Type B DTCs.
Conditions for Clearing the DTC
DTC P0449, P0498 and P0499 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Powertrain Component View
Powertrain Component Views
Description and Operation
Evaporative Emission Control System Description
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
NOTE: An audible click may be heard when performing step 2 below.
1. Ignition ON.
2. Command the EVAP Vent Solenoid Valve to ON (Not Venting) and OFF (Venting)
with a scan
tool while observing the following control circuit status parameters:
- EVAP Vent Solenoid Valve Control Circuit Open Test Status
- EVAP Vent Solenoid Valve Control Circuit Low Voltage Test Status
- EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status
- If Malfunction is displayed
Refer to Circuit/System Testing
- Go to next step: If Malfunction is not displayed
3. Verify the EVAP Vent Solenoid Valve control circuit parameters above do
not display Malfunction
when moving the related harnesses and connectors of the Q13 Evaporative Emission
Vent
Solenoid Valve.
- If Malfunction is displayed
Refer to Circuit/System Testing
- Go to next step: If Malfunction is not displayed
4. 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.
5. Verify the DTC does not set.
Refer to Circuit/System Testing
- Go to next step: If the DTC does not set
6. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the Q13 Evaporative
Emission Vent Solenoid
Valve, Ignition ON,
2. Verify that a test lamp illuminates between the B+ circuit terminal B or 2
and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the test lamp.
- 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, remove the test lamp.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, test all components connected to the B+
circuit for a short and
replace as necessary.
- Go to next step: If the test lamp illuminates
3. Verify that a test lamp does not illuminate between the B+ circuit
terminal B or 2 and the control
circuit terminal A or 1.
- If the test lamp illuminates
- 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 does not illuminate
4. Remove the test lamp.
5. Verify the scan tool EVAP Vent Solenoid Valve Control Circuit High Voltage
Test Status
parameter is OK when commanding the EVAP Vent Solenoid Valve to ON (Not Venting)
with a
scan tool.
If OK is not displayed
- Ignition OFF, 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.
- If less than 1 V, replace the K20 Engine Control Module.
Go to next step: If OK is displayed
6. Install a 3 A fused jumper wire between the control circuit terminal A or
1 and the B+ circuit
terminal B or 2.
7. Verify the scan tool EVAP Vent Solenoid Valve Control Circuit High Voltage
Test Status
parameter is Malfunction when commanding the EVAP Vent Solenoid Valve to ON (Not
Venting)
with a scan tool.
- If Malfunction is not displayed
- Ignition OFF, remove the jumper wire, disconnect the harness connector
at the K20 Engine
Control Module.
- 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.
- Go to next step: If Malfunction is displayed
8. Test or replace the Q13 Evaporative Emission Vent Solenoid Valve.
Component Testing
1. Ignition OFF, disconnect the harness connector at the Q13 Evaporative
Emission Vent Solenoid
Valve.
2. Test for 10-30 Ω between the control terminal A or 1 and the B+ circuit
terminal B or 2.
Replace the Q13 Evaporative Emission Vent Solenoid Valve.
- Go to next step: If between 10-30 Ω
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Control Module References for ECM replacement, programming and setup.
- Evaporative Emission Canister Solenoid Replacement (FWD) or Evaporative
Emission
Canister Solenoid Replacement (AWD) for EVAP Vent Solenoid Valve
replacement.
DTC P0451-P0454
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 P0451
Fuel Tank Pressure Sensor Performance
DTC P0452
Fuel Tank Pressure Sensor Circuit Low Voltage
DTC P0453
Fuel Tank Pressure Sensor Circuit High Voltage
DTC P0454
Fuel Tank Pressure Sensor Circuit Intermittent
Diagnostic Fault Information
Typical Scan Tool Data
Fuel Tank Pressure Sensor Voltage
Circuit/System Description
The fuel tank pressure sensor measures vapor pressure or vacuum in the
evaporative emission (EVAP)
system. The engine control module (ECM) supplies a 5 V reference and a low
reference circuit to the
fuel tank pressure sensor. The fuel tank pressure sensor signal voltage varies
depending on EVAP system
pressure or vacuum. The controller also uses this fuel tank pressure signal to
determine atmospheric
pressure for use in the engine-off small leak test, DTC P0442. Before using this
signal as an atmospheric
reference it must first be re-zeroed.
Conditions for Running the DTC
P0451
- DTC P0451 runs only when the engine-off natural vacuum small leak test,
P0442, executes.
- The number of times this test runs can range from 0 - 2 per engine-off
period. The length of the
test can be up to 10 min.
P0452 and P0453
DTC P0452 and P0453 run continuously when the ignition is ON.
P0454
- DTC P0454 runs only when the engine-off natural vacuum small leak test,
P0442, executes.
- This test can run once per engine-off period. The length of the test can
be up to 10 min.
- A refueling event is not detected. A refueling event is confirmed if the
fuel level has a persistent
change of 10% for 30 s during a 10 min refueling rationality test.
Conditions for Setting the DTC
P0451
This DTC will set if the controller is unable to re-zero the fuel tank
pressure sensor voltage within a
calibrated range during the engine-off small leak test, P0442.
P0452
The fuel tank pressure sensor voltage is less than 0.15 V for greater than 10
s.
P0453
The fuel tank pressure sensor voltage is greater than 4.9 V for greater than
10 s.
P0454
If, during the engine-off natural vacuum small leak test, P0442, the ECM
detects an abrupt fuel tank
pressure signal change, other than a refueling event, this DTC will set. An
abrupt change is defined as a
change of greater than 0.45 in H2O (0.11 kPa) in the span of 1 s but less than 1
in H2O (0.25 kPa) in
12.5 ms. This test must fail twice to set this DTC.
Action Taken When the DTC Sets
- DTCs P0451 and P0454 are Type A DTCs.
- DTCs P0452 and P0453 are Type B DTCs.
Conditions for Clearing the MIL/DTC
- DTCs P0451 and P0454 are Type A DTCs.
- DTCs P0452 and P0453 are Type B DTCs.
Diagnostic Aids
P0451 and P0454
- A restriction in the EVAP canister or vent lines could prevent fuel
vapor pressure from bleeding
off fast enough. If the vent system cannot bleed off pressure fast enough,
the re-zero procedure
may not complete successfully, which could cause this DTC to set.
- Ensure that the reference port on the fuel tank pressure sensor is
unobstructed.
- An fuel tank pressure sensor that is skewed or does not have a linear
transition from low to high
may cause this DTC to set. Scan tool control functions, snapshot, and plot
functions can help
detect erratic sensor response. To test the sensor signal under vacuum
conditions, use the Quick
Snapshot and the Purge/Seal functions to capture data while commanding purge
to 20%, then plot
the data to look for erratic sensor operation. A similar test can be done
for the pressure side of the
sensor operation by applying pressure with the GE-41413-A while taking a
snapshot.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Powertrain Component View
Powertrain Component Views
Description and Operation
Evaporative Emission Control System Description
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
Special Tools
GE-41413-A Evaporative Emission System Tester
For equivalent regional tools, refer to Special Tools (Diagnostic Tools) and
Special Tools (Mechanical Tools).
Circuit/System Verification
1. Remove the fuel cap.
2. Ignition ON, engine OFF.
3. Verify the scan tool Fuel Tank Pressure sensor parameter is between 1.3 and
1.7 V.
- If not between 1.3 - 1.7 V
Refer to Circuit/System Testing.
- Go to next step: If between 1.3 - 1.7 V
4. 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.
5. Verify the DTC does not set.
Refer to Circuit/System Testing.
- Go to next step: If the DTC does not set
6. All OK.
Circuit/System Testing
1. Ignition OFF, all vehicle systems OFF, this may take up to 2 min, for all
vehicle systems to power
down. Disconnect the harness connector at the B150 Fuel Tank Pressure Sensor.
2. Test for less than 5 Ω of resistance between the low reference circuit
terminal 2 and ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for less than 2 Ω in the low reference 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.
- Go to next step: If less than 5 Ω
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the 5 V reference circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 5 V reference 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.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module, ignition
ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If between 4.8 - 5.2 V
5. Verify the scan tool Fuel Tank Pressure parameter is less than 0.2 V.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module, ignition
ON
- Test for less than 1 V between the signal circuit terminal 1 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If less than 0.2 V
6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and
the 5 V reference circuit
terminal 3.
7. Verify the scan tool Fuel Tank Pressure sensor parameter is greater than 4.7
V.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the signal circuit terminal 1 and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal 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.
- Go to next step: If greater than 4.7 V
8. Test or replace the B150 Fuel Tank Pressure Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Fuel Tank Pressure Sensor Replacement (FWD) or Fuel Tank Pressure Sensor
Replacement
(AWD)
- 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:
Warning:
Exhaust gases can enter the
vehicle if it is driven with the
liftgate, trunk/hatch open, or with
any objects that pass through the
seal between the body and the
trunk/hatch or liftgate. Engine
exhaust contains carbon
monoxide (CO) which cannot be
seen or smelled. It can cause
unconsciousnes
Exterior Lamps
The exterior lighting system consist of the following lamps:
Adaptive forward lighting
Automatic headlamp leveling
Automatic high beam assist
Backup lamps
Daytime running lamps
Exterior courtesy lamps
Front fog lamps
Hazard warning lamps
Headlamps
Park, tail, license and ma