Isuzu N-Series. Manual - part 682
6E-150 Engine Control System (4HK1)
P0236 (Flash Code 65)
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 engine control module (ECM)
monitors the boost pressure sensor signal for abnormal
values. If the ECM detects that the boost pressure
sensor signal is excessively low, this DTC will set.
Condition for Running the DTC
• DTCs P0107, P0108, P0237, P0238, P1630 and
P1634 are not set.
• The ignition switch is ON.
• The ignition voltage is more than 18 volts.
• The engine is running.
• The fuel injection quantity is higher than a
predetermined value.
Condition for Setting the DTC
Either of following condition is met:
• The ECM detects that the boost pressure is lower
than 78 kPa (11 psi) for 20 seconds when the
engine speed is lower than 900 RPM.
• The ECM detects that the boost pressure is lower
than 82 – 151 kPa (12 – 22 psi) for 20 seconds
when the engine speed is between 1200 – 3000
RPM.
• The ECM detect that the boost pressure is lower
than 100 – 158 kPa (15 – 23 psi) for 20 seconds
when the engine speed is between 3300 – 3600
RPM.
Notice:
• If the barometric pressure (BARO) is lower than
100 kPa (15 psi), a compensated value (100 kPa –
BARO) is added to the above thresholds.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicator
lamp (MIL) when the diagnostic runs and fails.
Condition for Clearing the MIL / DTC
• The ECM turns OFF the MIL when the key is
cycled after a current DTC clears.
• A current DTC clears when the diagnostic runs and
does not fail.
• A history DTC clears after 20 consecutive driving
cycles without a fault. Or clear with the Tech 2 or
accelerator pedal operation.
Diagnostic Aid
• Induction air leakage can cause a low boost
pressure condition. A whistling noise may be heard
if a component is allowing air to enter the induction
system. Close the throttle plate, remove the boost
pressure sensor and introduce shop air into the
line. Feel around the air tubing for leaks.
• Check for cracked air tubing that may only open
during certain engine movement conditions.
• Check the turbocharger wastegate valve for a
sticking or stuck open condition.
• Use the Tech 2 to verify the integrity of the boost
pressure sensor signal. Compare the sensor
values under all load conditions for an excessively
low value. Use the Tech 2 data list values for
nominal sensor readings.
• Fuel system problem (low fuel pressure condition)
may set this DTC.
Test Description
The numbers below refer to the step number on the
diagnostic table.
3. A skewed boost pressure sensor value (shifted to a
low pressure) can set this DTC. The Boost Pressure on
the Tech 2 should read near barometric pressure
(BARO) with the key ON and engine OFF.
4. A BARO sensor value (shifted to a higher pressure)
may indicate a wrong boost pressure sensor reading.
The BARO on the Tech 2 should read near surrounding
barometric pressure.
DTC P0236 (Flash Code 65)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views
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