Dtc P253A (Flash Code 28) - Isuzu N 2008 Series Workshop Manual

1A-286 Engine Control System (4JJ1)

DTC P253A (Flash Code 28)

Circuit Description
The power take off (PTO) throttle sensor (body builder
installed) detects the PTO control throttle angle. The
ECM receives the PTO control throttle angle from the
throttle sensor and controls the fuel injection quantity
(engine speed) during PTO. The PTO throttle sensor
has the following circuits.
• 5 volts reference circuit
• Low reference circuit
• PTO throttle sensor signal circuit
The PTO throttle sensor provides a signal to the ECM
on the signal circuit, which is relative to the position
changes of the PTO throttle angle. If the ECM detects
an excessively high signal voltage, this DTC will set.
Condition for Running the DTC
• DTCs P060B and P0641 are not set.
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the PTO throttle sensor
signal voltage is more than 4.8 volts.
Circuit/ System Testing DTC P253A
Step
Did you perform the Diagnostic System Check -
1 Engine Controls?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
Notice: If no PTO throttle sensor is installed,
skip to Step 3.
2
4. Observe the PTO Remote Throttle Sensor
parameter with a scan tool while operating the
PTO throttle sensor.
Does the scan tool indicate more than the specified
value during operating the throttle?
Monitor the DTC Information with a scan tool.
3
Is DTC P0641 also set?
1. Turn OFF the ignition.
2. Disconnect the PTO throttle sensor harness
connector.
4
3. Turn ON the ignition, with the engine OFF.
Is the PTO Remote Throttle Sensor parameter less
than the specified value?
Action
Action Taken When the DTC Sets
• The ECM illuminates the SVS lamp when the
diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C. (Euro 4 specification)
• 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.
(Except Euro 4 specification)
• The ECM disables PTO throttle sensor control.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the SVS Lamp/ DTC - Type C. (Euro 4
specification)
• Refer to DTC Type Definitions for Condition for
Clearing the MIL/ DTC - Type A. (Except Euro 4
specification)
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
• PTO throttle sensor may have an intermittent open
somewhere in the operating range.
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Value(s) Yes
—
Go to Step 2
4.8 volts
Go to Step 3
—
Go to Step 4
0.1 volts
Go to DTC P0641
No
Go to Diagnostic
System Check -
Engine Controls
Go to Diagnostic
Aids
Go to Step 5
Go to Step 7