1A-146 Engine Control System (4HK1)
DTC P0234 (Flash Code 42)
Circuit Description
The boost pressure sensor is located in the air
induction tubing. The sensor is a transducer that varies
voltage according to changes in the air pressure inside
the air tubing. The ECM monitors the boost pressure
sensor signal for abnormal values. If the ECM detects
that the sensor signal is excessively high, this DTC will
set. This indicates excessive high boost pressure.
Condition for Running the DTC
• DTCs P0045, P0107, P0108, P060B, P0697,
U0073 and U0110 are not set.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the boost pressure is higher
than 130 to 240 kPa (19 to 35 psi) for longer than 5
seconds.
Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic
runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity
• The ECM inhibits EGR control.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the MIL/ DTC - Type A.
Diagnostic Aids
• An open circuit or high resistance in the boost
pressure low reference circuit may set this DTC.
• Check the turbocharger nozzle control solenoid
valve for a sticking.
• Use a scan tool to verify the integrity of the boost
pressure sensor signal. Compare the sensor
values under all load conditions for an excessively
high value.
• The fuel with which gasoline was mixed may set
this DTC.
Test Description
The numbers below refer to the step number on the
Circuit/ System Testing.
3. A skewed boost pressure sensor value (shifted to a
higher pressure) can set this DTC. The Boost Pressure
on the scan tool should read near Barometric Pressure
(BARO) with the ignition switch ON and engine OFF.
4. A skewed BARO sensor value (shifted to a lower
pressure) may indicate a wrong boost pressure. The
BARO on the scan tool should read near surrounding
barometric pressure.
Schematic Reference:
Engine Controls Schematics
Connector End View Reference:
Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0234
Step
Action
Value(s)
Yes
No
1
Did you perform the Diagnostic System Check
- Engine Controls?
—
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
2
1.
Install a scan tool.
2.
Turn OFF the ignition for 30 seconds.
3.
Start the engine.
4.
Monitor the DTC Information with a scan tool.
Is DTC P0045, P0107, P0108, P0638, P2227,
P2228 or P2229 also set?
—
Go to Applicable
DTC
Go to Step 3
3
1.
Turn ON the ignition, with the engine OFF.
2.
Observe the Boost Pressure and Barometric
Pressure (BARO) with a scan tool.
Does the scan tool indicate that the difference
between the Boost Pressure and BARO is
more than the specified value?
10 kPa (1.5
psi)
Go to Step 4
Go to Step 5
4
Compare the BARO value to the range specified in
the altitude vs. barometric pressure table. Refer to
Altitude vs Barometric Pressure.
Is the BARO parameter within the range
specified?
—
Go to Step 6
Go to Step 7
LG4HKED-WE-0871.book 146
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