Dtc242 - Idle Position Switch Circuit Short - Isuzu 4HL1 Workshop Manual

1A-206 Engine Control System

DTC242 - Idle Position Switch Circuit Short

Circuit Description
The idle position switch is installed to the accelerator
pedal, and is turned off when the pedal is pressed and
turned on when the pedal is released. The ECM
receives the on/off signal from this idle position switch
and uses it in exhaust brake control, warm-up control,
and other control tasks.
DTC242 will be set when accelerator pedal is in idle
position but the signal from the idle position switch is
being turned on.
Major Faulty Event
(When the AP sensor is also faulty.)
• Short power
• Poor pedal response
• Poor driveability
Conditions for Setting the DTC
The state where the AP sensor is in normal condition,
the AP sensor output voltage is 1 V or more, and the
idle position switch is turned on lasts at least 10
seconds.
Action Taken When the DTC Sets
• After the DTC is set, the ECM will illuminate the
CHECK ENGINE lamp (MIL).
• Exhaust brake and warm-up systems are disabled.
7. Turn off the starter switch. Wait for 5 seconds and
110
90 84 94 108
Idle
Switch
AP
Sensor
Conditions for Clearing MIL/DTC
When the system fails and the DTC is stored to the
ECM, even repairing the faulty portion will not clear the
DTC from the memory. To clear the DTC, conduct the
following steps.
ECM
(Engine
Control
Module)
• In case of AP sensor fault, the ECM controls the
powertrain using the set accelerator position (20
%).
1. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
2. Turn on the idle position switch for not less than 1
second but not more than 3 seconds. (Release the
accelerator pedal.)
3. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
4. Turn on the idle position switch for not less than 1
second but not more than 3 seconds. (Release the
accelerator pedal.)
5. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
6. After the above operations are properly completed,
the CHECK ENGINE lamp (MIL) illuminates for 3
seconds to report the memory is cleared.
turn on the starter switch again.
LNW21AMF007501-X