Isuzu Rodeo UE. Manual — part 399

6E2–351

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

passage and on the IAC pintle, and excessive deposits
in the throttle bore and on the throttle plate.

f

Large vacuum leak – Check for a condition that causes
a large vacuum leak, such as an incorrectly installed or
faulty PCV valve or brake booster hose disconnected.

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.

DTC P0506 – Idle Air Control System Low RPM

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

2

Are any other DTCs set?

—

Go to other

DTC first

Go to

Step 3

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 the “Engine Speed” remain within the specified
value of “Desired Idle” for each RPM command?

±

50 RPM

No trouble

found. Go to

Diagnostic

Aids

Go to

Step 4

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”)?

—

Go to

Step 6

Go to

Step 5

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?

—

Verify repair

Go to

Step 9

6E2–352

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0506 – Idle Air Control System Low RPM

(Cont'd)

Step

No

Yes

Value(s)

Action

6

Visually/physically inspect for the following conditions:

f

Restricted air intake system. Check for a possible
collapsed air intake duct, restricted air filter
element, or foreign objects blocking the air intake
system.

f

Throttle body. Check for objects blocking the IAC
passage or throttle bore, excessive deposits in
the IAC passage and on the IAC pintle, and
excessive deposits in the throttle bore and on the
throttle plate.

Do any of the above require a repair?

—

Refer to

appropriate

section for
on-vehicle

service

Go to

Step 7

7

1. Check for a poor connection at the IAC harness

connector.

2. If a problem is found, replace faulty terminals as

necessary.

Was a problem found?

—

Verify repair

Go to

Step 8

8

Replace the IAC valve.

Is the action complete?

—

Verify repair

—

9

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

6E2–353

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0507 Idle Air Control System High RPM

T321115

Circuit Description

The powertrain control module (PCM) controls engine
idle speed by adjusting the position of the idle air control
(IAC) motor pintle. The IAC is a bi-directional stepper
motor driven by two coils. The PCM applies current to the
IAC coils in steps (counts) to extend the IAC pintle into a
passage in the throttle body to decrease air flow. The
PCM reverses the current to retract the pintle, increasing
air flow. This method allows highly accurate control of idle
speed and quick response to changes in engine load. If
the PCM detects a condition where too high of an idle
speed is present and the PCM is unable to adjust idle
speed by increasing the IAC counts, DTC P0507 will set,
indicating a problem with the idle control system.

Conditions for Setting the DTC

f

No Tech 2 test is being run.

f

No TPS, VSS, ECT, EGR, MAF, MAP, IAT, misfire, low
voltage, fuel system, canister purge, injector control or
ignition control DTCs are set.

f

Barometric pressure is above 75 kPa.

f

Canister purge duty cycle is above 10%.

f

Engine running time is more than 125 seconds.

f

Vehicle speed is less than 1 mph.

f

Engine coolant temperature (ECT) is above 50

°

C.

f

Ignition voltage is between 9.5 volts and 16.7 volts.

f

The throttle is closed.

f

EVAP purge duty cycle is more than 10%.

f

All conditions are met for 10 seconds.

f

Engine speed is more than 100-200 RPM higher than
desired idle based upon coolant temperature.

Action Taken When the DTC Sets

f

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

f

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

f

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

f

A history DTC P0507 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

f

DTC P0507 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

f

Poor connection at PCM or IAC motor – Inspect
harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire
connection.

f

Damaged harness – Inspect the wiring harness for
damage.

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

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.

DTC P0507 – Idle Air Control System High RPM

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

2

Are any other DTCs set?

—

Go to other

DTC first

Go to

Step 3

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?

±

50 RPM

No trouble

found. Go to

Diagnostic

Aids

Go to

Step 4

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”)?

—

Go to

Step 6

Go to

Step 5

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?

—

Verify repair

Go to

Step 9