Isuzu KB P190. Manual - part 470
ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-263
DTC P2122 or P2123 (Flash Code 121)
Circuit Description
The accelerator pedal position (APP) sensor is
mounted on the accelerator pedal control assembly.
The sensor is made up of three individual sensors
within one housing. The ECM uses the APP sensors to
determine the amount of acceleration or deceleration
that is desired. The APP sensor 1 has the following
circuits.
• 5 volts reference circuit
• Low reference circuit
• APP sensor 1 signal circuit
The APP sensor 1 provides a signal to the ECM on the
signal circuit, which is relative to the position changes
of the accelerator pedal angle. If the ECM detects an
excessively low or high signal voltage, DTC P2122 or
P2123 will set.
Condition for Running the DTC
• DTCs P0642 and P0643 are not set.
• The battery voltage is more than 9 volts.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the APP sensor 1 signal
voltage is less than 0.15 volts. (DTC P2122)
• The ECM detects that the APP sensor 1 signal
voltage is more than 4.85 volts. (DTC P2123)
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 limits fuel injection quantity
• The ECM inhibits cruise 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.
• APP sensor 1 may have an intermittent open
somewhere in the pedal range.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P2122
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 P0642 also set?
—
Go to DTC P0642
Go to Step 3
3
Fully depress and release the accelerator pedal
while observing the Accelerator Pedal Position
(APP) Sensor 1 parameter with a scan tool.
Does the scan tool indicate less than the specified
value during depressing or releasing the pedal?
0.2 volts
Go to Step 4
Go to Diagnostic
Aids