Buick Regal: DTC P0236
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 P0236
Turbocharger Boost Sensor Performance
Circuit Description
The boost pressure sensor is integrated with the turbocharger boost/intake
air temperature sensor. The
boost pressure sensor measures the range of pressures between the turbocharger
and the throttle body.
The sensor used on this engine is a three atmosphere sensor. Pressure in this
portion of the induction
system is affected by engine speed, throttle opening, turbocharger boost
pressure, Intake air temperature
(IAT), barometric pressure (BARO), and the efficiency of the charge air cooler.
The sensor provides a signal voltage to the engine control module (ECM),
relative to the pressure
changes. Under normal operation the greatest pressure that can exist in this
portion of the induction
system at ignition ON, engine OFF is equal to the BARO. When the engine is
operated at wide-open
throttle (WOT) the turbocharger can increase the pressure to near 240 kPa (34.8
psi). The pressure is
equal to the BARO when the engine is idling or decelerating.
Conditions for Running the DTC
- DTC P0106, P0107, P0108, P0237, P0238, P2227, P2228, P2229, or P2230 is
not set.
- DTC P0106, P0107, P0108, P0237, or P0238 is not pending.
- Ignition is ON.
- Engine is OFF.
- The time between current ignition cycle and the last time the engine was
running is greater than
10 s.
- The DTC runs continuously when the above conditions have been met.
OR
- DTC P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0114, P0116,
P0117, P0118, P0128,
P0237, P0238, P0335, P0336, P2227, P2228, P2229 or P2230 is not set.
- DTC P0112, P0113, P0117, or P0118 is not pending.
- Engine speed is between 400 - 6, 000 RPM.
- Engine Coolant Temperature (ECT) is between -7 to +125ºC (19.4 -
257ºF).
- Intake Air Temperature (IAT) is between -20 to +125ºC (-4 to +257ºF).
- The DTC runs continuously when the above conditions have been met.
Conditions for Setting the DTC
- The ECM detects that the boost pressure sensor signal is not within
range of a model derived from
engine speed, the BARO sensor, the MAF sensor, the MAP sensor, the throttle
position sensor and
the turbocharger boost pressure sensor when the engine is running.
OR
- The ECM detects that the boost pressure sensor signal is less than 50
kPa (7.3 psi) or greater than
115 kPa (16.7 psi) when the ignition is ON and the engine is NOT rotating.
OR
- The ECM detects that the difference between MAP and BARO is less than or
equal to 10 kPa and
the difference between turbocharger boost pressure and MAP is greater than
10 kPa and the
difference between turbocharger boost pressure and BARO is greater than 10
kPa when the
ignition is ON and the engine is NOT rotating.
Action Taken When the DTC Sets
DTC P0236 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0236 is a Type B DTC.
Diagnostic Aids
- The charge air cooler is connected to the turbocharger and to the
throttle body by flexible duct
work that requires the use of special high torque fastening clamps. These
clamps cannot be
substituted. In order to prevent any type of air leak when servicing the
duct work, the tightening
specifications and proper positioning of the clamps is critical, and must be
strictly adhered to.
- Use a smoke generating device or a solution of dish soap and water in a
spray bottle to pinpoint
any suspected air leaks in the induction system and in the charge air cooler
assembly.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Description and Operation
Turbocharger 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
1. Verify that DTC P0641, P0651, P0697, P06A3, or P06D2 is not set.
Refer to Diagnostic Trouble Code (DTC) List - Vehicle.
- Go to next step: If none of the DTCs are set
2. If you were sent here from DTC P0068, P0101, P0106, P0121, or P1101 refer
to Circuit/System
Testing.
3. Ignition ON.
4. Verify the scan tool Throttle Body Idle Airflow Compensation parameter is
less than 90%.
Refer to Throttle Body Cleaning.
- Go to next step: If less than 90%
5. Verify the scan tool Throttle Position Sensors 1 and 2 Agree/Disagree
parameter displays Agree
while performing the Throttle Sweep Test with a scan tool.
Refer to DTC P0121-P0123, P0222, P0223, P16A0-P16A2, or P2135.
- Go to next step: If Agree
6. Verify the scan tool BARO parameter is within the range specified in the
Altitude Versus
Barometric Pressure table, for the current vehicle testing altitude.
Refer to DTC P2227-P2230.
- Go to next step: BARO is within range
7. Verify the scan tool MAP Sensor pressure and BARO parameters are within 3
kPa (0.4 psi).
- The parameters are not within 3 kPa (0.4 psi).
Refer to DTC P0106.
- Go to next step: The parameters are within 3 kPa (0.4 psi).
8. Engine idling.
9. Verify the scan tool MAP Sensor pressure parameter is between 26 - 52 kPa
(3.8 - 7.5 psi) and
changes with accelerator pedal input.
- If not between 26 - 52 kPa (3.8 - 7.5 psi) or does not change
Refer to DTC P0106.
- Go to next step: If between 26 - 52 kPa (3.8 - 7.5 psi) and changes
10. Verify the scan tool MAF Sensor g/s parameter changes smoothly and
gradually as the engine
speed is increased and decreased while performing the actions listed below.
- Engine idling
- Perform the scan tool snapshot function.
- Increase the engine speed slowly to 3, 000 RPM and then back to idle.
- Exit from the scan tool snapshot and review the data.
- Observe the MAF Sensor parameter frame by frame with a scan tool.
- The MAF Sensor parameter does not change smoothly and gradually
Refer to DTC P0101.
- Go to next step: The MAF Sensor parameter changes smoothly and
gradually
12. Verify the scan tool MAP Sensor parameter and the Boost Pressure Sensor
parameter are within
20 kPa (2.9 psi) during a WOT acceleration at the time of the 1-2 shift.
- The parameters are not within 20 kPa (2.9 psi)
Refer to Circuit/System Testing.
- Go to next step: The parameters are within 20 kPa (2.9 psi)
13. 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.
14. Verify a DTC does not set.
Refer to Circuit/System Testing.
- Go to next step: If the DTC does not set
15. All OK.
Circuit/System Testing
1. Verify that DTC P0237 or P0238 is not set.
Refer to DTC P0237 or P0238.
- Go to next step: If none of the DTCs are set
2. Verify the conditions listed below do not exist:
- Loose clamps, cracks, or other damage in the air intake duct system
- Collapsed or restricted air intake duct system
- Restricted air filter
- Splits, kinks or improper connections at the vacuum hoses
- Missing, restricted or leaking exhaust components - Refer to Symptoms -
Engine Exhaust.
- Vacuum leaks at the intake manifold and throttle body
- If a condition exists
Repair as necessary.
- Go to next step: If none of the conditions exist
3. Replace the B111B turbocharger boost/intake air temperature sensor.
Repair Instructions
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:
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
DT
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