FUEL SYSTEM <4D5-step
III
> - Troubleshooting
13-11
Code No. 12 Boost pressure sensor (boost sensor)
system
Probable cause
Range of Check
D
Ignition switch: ON, except for during engine cranking
Set Conditions
D
Sensor output voltage for 1 second is 4.5 V or higher
(boost pressure is approximately 267 kPa).
or
D
Sensor output voltage for 1 second is 0.2 V or lower
(boost pressure is approximately 51.7 kPa or lower)
Range of Check
D
Engine speed is 2,000 r/min or higher, barometric pressure is 69.7 kPa or
less (equivalent to an altitude of 300 m) and under high load.
Set Conditions
D
Boost pressure is lower than the barometric pr 13 kPa for 3
seconds.
D
Boost pressure sensor inoperative
D
Boost pressure sensor open circuit, short circuit,
or connector contact inoperative
D
Boost pressure sensor hose disconnected
D
Engine-ECU inoperative
NG
Check the trouble symptoms.
Replace the engine-ECU.
Check the following connector:
C-43
NG
OK
NG
Repair
Repair
OK
NG
Check the trouble symptoms.
OK
OK
OK
Check the following connector:
A-129
NG
Check the trouble symptoms.
NG
Repair
NG
NG
Check the vacuum hose between the
boost pressure sensor and the intake
manifold.
Replace the boost pressure sensor.
OK
OK
OK
Repair
NG
Repair
Check the trouble symptoms.
Check the harness between the
engine-ECU and the boost pressure
sensor connector, and repair if
necessary.
NG
OK
NG
Repair
Check the following connector:
A-129
NG
Measure at A-129 boost pressure
sensor connector
D
Connect the connector.
(Test harness: MB991348 used)
D
Voltage between 1 and the earth
(Engine: Idling)
OK:
1.3 - 1.7 V
D
Voltage between 1 and the earth
OK:
When the accelerator pedal
is suddenly pressed from
the idling condition, the
voltage temporarily in-
creases from 1.3 V to 1.7
V.
Measure at C-43 engine-ECU
connector
D
Connect the connector.
D
Voltage between 85 and the
earth (Engine: Idling)
OK:
1.3 - 1.7 V
Check the harness between the
engine-ECU and the boost pressure
sensor connector.
Measure at A-129 boost pressure
sensor connector
D
Disconnect the connector and
measure at the harness side.
D
Voltage between 3 and the earth
(Ignition switch: ON)
OK:
4.5 - 5.5 V
D
Continuity between 2 and the
earth
OK:
Continuity
NG
Check the harness between the
engine-ECU and the boost pressure
sensor connector.
Replace the engine-ECU.
OK
NG
Repair
Checkthefollowingconnector:
C-130