4.
Monitor "BOOST PRESSURE SENSOR" parameter on the Scantool.
Specification : 1028hpa ± 100hpa(VGT actuator : 75%) at idle
Boost Pressure Sensor(BPS) is installed in intake manifold and senses the pressure of air inside of intake manifold which is compressed by turbo charager.Measuring mass air flow accurately with the information of intake mainfold pressure, mass air flow and intake air temperature, ECM performs actuating correction of EGR and VGT.When excessive intake manifold pressure is detected, engine power generation is limited to protect engine because too highly compressed pressure due to turbo charger may harm engine.
P0238 is set when the voltage above 4900mV - maximum output voltage of BPS - is detected for more than 2.0 sec.. This code is due to short to battery in BPS signal circuit or open in ground circuit.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● BPS circuit ● BPS component | ||
Enable Conditions | ● IG KEY "ON" | |||
ThresholdValue | ● Output signal above maximum value(above 4900mV) | |||
DiagnosticTime | ● 2.0 sec | |||
Fail Safe | Fuel Cut | NO | ● Boost pressure is fixed at 1000 hpa. | |
EGR Off | YES | |||
Fuel Limit | YES | |||
MIL | NO | |||
Pressure [Kpa] | 20 | 100 | 190 | 250 |
Outpur voltage [V] | 0.4±0.077 | 1.878±0.063 | 3.541±0.063 | 4.650±0.077 |
Connect Scantool to Data Link Connector (DLC).
Warm engine up to normal operating temperature.
Turn "OFF" electrical devices and A/C.
Monitor "BOOST PRESSURE SENSOR" parameter on the Scantool.
Specification : 1028hpa ± 100hpa(VGT actuator : 75%) at idle
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Power Circuit Inspection".
IG KEY "OFF", ENGINE "OFF".
Disconnect BPS connector.
IG KEY "ON".
Measure the voltage of BPS connector terminal 2.
Specification : 4.8V~5.1V
Is the measured voltage within the specification?
▶ Go to "Signal Circuit Inspection".
▶ Sensor power too high : Refer to circuit inspection of P0653.
Check signal circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect BPS connector.
IG KEY "ON".
Measure the voltage of BPS connector terminal 1.
Specification : below 0.1V
Is the measured voltage within the specification?
▶ Go to "Ground Circuit Inspection".
▶ Repair short to battery in signal circuit and go to "Verification of Vehicle Repair".
IG KEY "OFF", ENGINE "OFF".
Disconnect BPS connector.
IG KEY "ON".
Measure the voltage of BPS connector terminal 2. [ TEST "A" ]
Measure the voltage between BPS connector terminal 2 and 4. [ TEST "B" ]
( terminal 2 : Check + prove , terminal 4 : Check - prove )
Specification : [TEST "A"] Voltage - [TEST "B"] Voltage = below 200mV
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ When "B" voltage is not detected : Repair open in ground circuit and go to "Verification of Vehicle Repair".
▶ When the voltage difference between "A" and "B" is above 200mV : Eliminate the causes of excessive resistance and go to "Verification of Vehicle Repair".
BPS visual inspection
IG KEY "OFF", ENGINE "OFF".
Disconnect BPS connector.
Check if corrosion and damage in BPS terminal is detected.
Check BPS mounting state, leakage at O'ring, clogged carbon at pressure detecting hall.
Are the problems relevant to BPS found?
▶ Replace BPS if necessary and go to "Verification of Vehicle Repair".
▶ Go to "2. Check VGT Turbo charger and leakage in intake system".
Check VGT turbo charger and leakage in intake system
IG KEY "OFF", ENGINE "OFF".
Check if VGT actuating rod which is connected to diaphragm of VGT turbo charger assy' is at the bottom position.
IG KEY "ON"., ENGINE "ON".
Check if VGT actuating rod is pulled upward Approx. 10mm when engine is about to start.
As accelerating and decelerating, Check if VGT actuating rod moves upward and downward.
Check if intake air leak is detected at intake hose at acceleration.
(Check if intake hose inflates properly.)
Are the problems relevant to VGT turbo charger and intake hose found?
▶ VGT actuating rod does not work.
☞ If any problem is not detected after checking connecting condition of VGT actuator vacuum hose and VGT actuator operating states(refer to "Component Inspection" of P0048 ), VGT actuator variable controlling part is considered as stuck. Replace VGT turbo charger in this case.
▶ Intake air leak is detected.
☞ Checking intake hose is not damaged and band clamp is fastened well, repair trouble causing parts.
If trouble causing parts are repaired, go to "Verification of Vehicle Repair".
▶ Go to "3. BPS Waveform inspection".
BPS Waveform inspection
IG KEY "ON", ENGINE "OFF".
Connect BPS.
Connect Oscilloscope to BPS connector terminal 1.
Monitor the waveform at idle and acceleration after ENGINE "ON".
Specification : Refer to "Signal Waveform & Data" of "General Information".
Is BPS waveform displayed correctly?
▶ Go to "Verification of Vehicle Repair".
▶ Replace BPS and go to "Verification of Vehicle Repair".
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
