DTC P0236, P0237, or P0238
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DTC P0236, P0237, or P0238
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DTC P0236
Turbocharger Boost System Performance
DTC P0237
Turbocharger Boost Sensor Circuit Low Voltage
DTC P0238
Turbocharger Boost Sensor Circuit High Voltage
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Diagnostic Fault Information
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Circuit
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Short to Ground
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High Resistance
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Open
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Short to Voltage
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Signal Performance
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5 V Reference
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P0642
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P0236, P0237
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P0237
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P0236, P0643
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P0234, P0236, P0299
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Boost Pressure Sensor Signal
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P0237
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P0236, P0237
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P0238
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P0238
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P0236
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Low Reference
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-
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P0238
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P0238
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-
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-
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Intake Air Pressure and Temperature Sensor
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Circuit
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Short to Ground
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Open
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Short to Voltage
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Operating Conditions:
Engine running at various operating conditions
Parameter Normal Range:
BARO to 240 kPa (35 psi)
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5 V Reference
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20-80 kPa
(2.9-11.6 psi)
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30-80 kPa
(4.4-11.6 psi)
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20-80 kPa
(2.9-11.6 psi)
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Intake Air Pressure Sensor Signal
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0 kPa
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276 kPa
(40 psi)
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276 kPa
(40 psi)
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Low Reference
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-
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276 kPa
(40 psi)
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-
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The boost pressure sensor is integrated with the intake air temperature (IAT) sensor. The boost pressure sensor measures the range of pressures between the turbocharger and the throttle body. Pressure in this portion of the induction system is affected by the following:
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Turbocharger boost pressure
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Intake air temperature (IAT)
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Barometric pressure (BARO)
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•
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Efficiency of the charge air cooler
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The sensor provides a signal voltage to the engine control module (ECM), relative to the pressure changes, on the boost pressure sensor signal circuit. 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 vehicle is operated at wide-open throttle (WOT) the turbocharger can increase the pressure to near 240 kPa (35 psi). The least amount of pressure that occurs is when the vehicle is idling or decelerating, and it is equal to the BARO.
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Conditions for Running the DTC
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P0236
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•
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DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0237, P0238, P2227, P2228, or P2229 are not set.
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•
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The engine speed is less than 1,120 RPM.
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The Throttle Position Sensor parameter is less than 10%.
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This DTC runs continuously within the enabling conditions.
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P0237
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•
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This DTC runs continuously within the enabling conditions.
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P0238
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This DTC runs continuously within the enabling conditions.
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Conditions for Setting the DTC
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P0236
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The ECM detects that the boost pressure sensor signal plus a calibrated threshold is less than the BARO sensor signal plus a calibrated threshold.
OR
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•
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The ECM detects that the boost pressure sensor signal plus a calibrated threshold greater than the BARO sensor signal plus a calibrated threshold.
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P0237
The ECM detects that the boost pressure sensor voltage is less than 0.45 V or the measured pressure is less than 50 kPa (7.3 psi).
P0238
The ECM detects that the boost pressure sensor voltage is greater than 4.65 V or the measured pressure is greater than 300 kPa (43.5 psi).
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Action Taken When the DTC Sets
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DTCs P0236, P0237, P0238, are Type B DTCs.
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Conditions for Clearing the MIL/DTC
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DTCs P0236, P0237, P0238, are Type B DTCs.
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•
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Use a solution of dish soap and water in a spray bottle to pinpoint any air leaks.
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The BARO sensor is integrated within the ECM, and it has a port on the housing that allows it to sense the ambient pressure. Any restriction at this opening may hinder the operation of the BARO sensor.
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Schematic Reference
Engine Controls Schematics (3.0L (LF1))
Engine Controls Schematics (2.8L (LAU))
Connector End View Reference
Component Connector End Views
Description and Operation
Turbocharger System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Ignition ON, observe the diagnostic trouble code (DTC) information with a scan tool. Verify that DTCs P0641, P0642, P0643, P2227, P2228, or P2229 are not set.
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3.
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Compare the scan tool BARO-parameter to the table
Altitude versus barometric pressure
The BARO should be within the specified range displayed in the table for the specific altitude above sea level.
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5.
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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.
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1.
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Verify the integrity of the entire air induction system including all turbocharger components by inspecting for the following conditions:
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Intake air pressure and temperature sensor damage
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A buildup of contamination, snow or ice at the BARO port on the ECM
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Loose or improper installation
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An air flow restriction
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Any type of air leak between the turbocharger and the throttle body
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2.
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If a condition is found, repair as necessary.
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3.
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Ignition OFF, disconnect the harness connector at the B65 intake air pressure and temperature sensor.
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4.
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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 5 Ω between the low reference circuit terminal 1 and ground.
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5.
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If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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6.
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Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
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7.
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If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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8.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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9.
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Verify the scan tool Boost Pressure Sensor parameter is greater than 250 kPa (36.3 psi).
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10.
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If lower than the specified range, test the signal circuit's pin 4 for a short to ground. If the circuit tests normal, replace the K20 ECM.
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11.
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Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 1. Verify the scan tool Boost Pressure Sensor parameter is less than 1 kPa (0.15 psi).
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12.
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If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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13.
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If the circuits test normal, test or replace the B65 intake air pressure and temperature sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
