Dtc34 - Ecm Internal Fault (Charge Circuit Fault) - Isuzu 4HL1 Workshop Manual

DTC34 - ECM Internal Fault (Charge Circuit Fault)

Circuit Description
The charge circuit in the ECM steps up the voltage for
injectors and is divided into two banks, common 1 and
common 2. Common 1 covers injectors in cylinders 1
and 4 and common 2 covers injectors in cylinders 2
and 3.
DTC34 will be set when the voltage on one of two
charge circuits is excessively high or low.
Major Faulty Event
• Short power
• Poor driveability
• Generation of black smoke
Conditions for Setting the DTC
The charge circuit voltage in the ECM is excessively
high or low.
Action Taken When the DTC Sets
• After the DTC is set, the ECM will illuminate the
CHECK ENGINE lamp (MIL).
• Fault judgment is disabled on injector drive
system.
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
23 24 5 4
Cylinder 4 Cylinder 1
Cylinder 2 Cylinder 3
43 2 1
42
following steps.
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.
7. Turn off the starter switch. Wait for 5 seconds and
turn on the starter switch again.
When Tech 2 has been connected to the vehicle, the
DTC can be cleared through the memory clear
operation with Tech 2.
Engine Control System 1A-129
ECM
(Engine
Control
Module
LNW21AMF007001-X