Malfunction Indicator Lamp - Isuzu C22NE Workshop Manual

6-14 ENGINE DIAGNOSIS (C22NE, 22LE, 20LE)

Malfunction Indicator Lamp

The instrument panel "CHECK ENGINE" Malfunction
Indicator lamp (MIL) illuminates by self diagnostic
system when the system checks the starting of
engine, or senses malfunctions.
Condition
"CHECK ENGINE" MIL does not
illuminate at the starting of engine
"CHECK ENGINE" MIL
illuminates, and stays on
Possible cause
Bulb defective
MIL circuit open
Command signal circuit to operate
self diagnostic system shorted
Engine Control Module (ECM)
cable loosely connected,
disconnected or defective
ECM defective
Deterioration heated oxygen
sensor of internal element
Heated oxygen sensor connector
terminal improper contact
(If applicable)
Heated oxygen sensor lead wire
shorted (If applicable)
Heated oxygen sensor circuit open
(If applicable)
Deterioration engine coolant
temperature sensor of internal
element
Engine coolant temperature
sensor connector terminal
improper contact
Engine coolant temperature
sensor lead wire shorted
Engine coolant temperature
sensor circuit open
Throttle position sensor open or
shorted circuits
Deterioration of crankshaft
position sensor
Crankshaft position sensor circuit
open or shorted
Vehicle speed sensor circuit open
Manifold absolute pressure sensor
circuit open or shorted
Intake air temperature sensor
circuit open or shorted
Fuel injector circuit open or shorted
ECM driver transistor defective
Malfunctioning of ECM RAM
(Random Access Memory) or
Malfunctioning of ECM PROM
(Programmed Read Only Memory)
Correction
Replace
Correct or replace
Correct or replace
Correct or replace
Replace
Replace
Reconnect properly
Correct
Correct or replace
Replace
Reconnect properly
Correct
Correct or replace
Correct or replace
Replace
Correct or replace
Correct or replace
Correct or replace
Correct or replace
Correct or replace
Replace EPROM or ECM
Replace EPROM or ECM