Isuzu 1999 RODEO Workshop Manual page 1597

6E2–354
RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
f Vacuum leak – Check for a condition that causes a
vacuum leak, such as disconnected or damaged
hoses, leaks at EGR valve and EGR pipe to intake
manifold, leak at the throttle body, a faulty or incorrectly
installed PCV valve, leaks at the intake manifold, etc.
f Throttle body – Check for sticking throttle plate. Also
inspect the IAC passage for deposits or objects which
DTC P0507 – Idle Air Control System High RPM
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 Are any other DTCs set?
3 1. Start the engine.
2. Turn all accessories "OFF" (A/C, rear defroster,
etc.)
3. Using a Tech 2, command RPM up to 1500, down to
500, and then up to 1500 while monitoring "Engine
Speed" on the Tech 2.
NOTE: This Tech 2 command may cause the engine to
"cut out" when RPM goes above 1500. If this occurs,
the "cutting out" will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500RPM.
Does "Engine Speed" remain within the specified value
of "Desired Idle" for each RPM command?
4 1. Disconnect the IAC.
2. Install IAC Node Light J 37027A or equivalent.
3. With the engine running, command RPM up to
1500, down to 500, and then up to 1500 while
observing the node light.
NOTE: This Tech 2 command may cause the engine to
"cut out" when RPM goes above 1500. If this occurs,
the "cutting out" will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500RPM.
Does each node light cycle red and green (never
"OFF")?
5 1. Check the following circuits for an open, short to
voltage, short to ground, or poor connection at the
PCM:
f
IAC "A" low
f
IAC "A" high
f
IAC "B" low
f
IAC "B" high
2. If a problem is found, repair as necessary.
Was a problem found?
Action
will not allow the IAC pintle to fully extend or properly
seat.
If DTC P0507 cannot be duplicated, reviewing the Failure
Records vehicle mileage since the diagnostic test last
failed may help determine how often the condition that
caused the DTC to be set occurs. This may assist in
diagnosing the condition.
Value(s)
Go to Step 2
—
Go to other
— DTC first
No trouble
found. Go to
Diagnostic
50 RPM
Go to Step 6
—
— Verify repair
Yes No
Go to OBD
System
Check
Go to Step 3
Aids Go to Step 4
Go to Step 5
Go to Step 9