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.
P0069 is set when the difference between BPS output voltage and atmospheric pressure sensor output voltage is above 300hpa at below 100RPM(in other word, IG KEY ON condition) for more than 3.0 sec. This code is due to abnormal output characteristic of BPS component.
Item
Detecting Condition
Possible Cause
DTC Strategy
Voltage monitoring
BPS circuit
BPS component
Enable Conditions
IG KEY "ON" (below 100RPM)
Threshold Value
|Boost pressure - Barometric pressure| is above 300hpa.
Diagnostic Time
3.0 sec.
Fail Safe
Fuel cut
YES
Boost pressure is fixed at 1000 hpa.
EGR Off
NO
Fuel Limit
Check Lamp
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
Fig.1) This is the waveform of BPS as accelerating from idle state. Signal voltage rises as accelerating.