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Isuzu Trooper (1998-2002 year). Manual - part 519

6E–446

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1639 Reference Voltage # 2 Circuit Fault

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Connect a DVM between the 5volt reference curcuit

and the AP1, AP2 and AP3 sensor ground curcuit.

2. Check the voltage using a DVM.

Is the voltage near the specified value?

Varify repair

Go to

Step 3

1. Check the APS1, APS2 and APS3 5 volt reference

curcuit.

2. If the curcuit is open or shorted, repair it as

necessary.

Was the curcuit open or short?

—

Varify repair

Go to

Step 4

1. Check the AP1, AP2 and AP3 sensor ground

curcuit.

2. If the curcuit is open or shorted, repair it as

necessary.

Was the curcuit open or short?

—

Varify repair

Go to

Step 5

1. Observe the battery voltage and circuit.
2. If a problem found, repair it as necessary.

Was a problem found?

—

Verify repair

Go to

Step 6

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed.

Refer to ON–Vehicle Service in Power 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 adtion complete?

—

Verify repair

—

6E–447

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1640 Driver-1-Output Circuit Fault (ODM)

Circuit Description

Output driver modules (ODMs) are used by the
powertrain control module (PCM) to turn “ON” many of
the current-driven devices that are needed to control
various engine and transmission functions. Each ODM is
capable of controlling up to 7 separate outputs by
applying ground to the device which the PCM is
commanding “ON”.
Unlike the Quad Driver Modules (QDMs) used in prior
model years, ODMs have the capability of diagnosing
each output circuit individually. DTC P1640 set indicates
an improper voltage level has been detected on an ODM
output.
Since A/C is an option, No A/C will cause the air
conditioning clutch relay output to always fail. If a fault is
seen on the air conditioning clutch relay output, it will not
be logged as a fault until the A/C request input interrupts a
high voltage, indicating that A/C has been installed.

Conditions for Setting the DTC

Ignition “ON”.

Engine running.

Ignition voltage is above 13.2 volts for 4 seconds.

Output voltage does not equal ignition voltage when
output is “OFF” or output voltage is not less than 1 volt
when output is “ON”.

Above conditions occur for at least 1 second.

Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

A history DTC P1640 will clear after 40 consecutive
warm-up cycles occur without a fault.

DTC P1640 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:

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

Damaged harness – Inspect the wiring harness for
damage, If the harness appears to be OK, disconnect
the PCM, turn the ignition “ON” and observe a
voltmeter connected to the suspect driver circuit at the
PCM harness connector while moving connectors and
wiring harnesses related to the MIL. A change in
voltage will indicate the location of the fault.

Poor connection at component – Examine for
damaged connectors, unplugged connector, or
damaged terminals at the following locations:
Instrument cluster harness, canister purge solenoid,
A/C clutch relay. An open ignition feed circuit at any of
these components will cause DTC P1640 to be set.

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 P1640 – Driver-1-Output Circuit Fault (ODM)

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Check the fuse for the driver circuit that was shown as
faulty.

Was the fuse blown?

—

Go to

Step 3

Go to

Step 4

1. Check for a short to ground between the fuse and

the affected component.

2. Replace the fuse after making any necessary

repairs.

Is the action complete?

—

Verify repair

—

Disconnect the PCM connector for the affected driver
circuit.

Is there any damage to the PCM pin or connector?

—

Go to

Step 5

Go to

Step 6

Repair the damaged pin or terminal.

Is the action complete?

—

Verify repair

—

Were either of the lamp circuits for “Check Engine” or
“Check Trans” indicated as faulty by the Tech 2?

—

Go to

Step 7

Go to

Step 13

6E–448

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P1640 – Driver-1-Output Circuit Fault (ODM)

(Cont'd)

Step

Yes

Value(s)

Action

1. Leave the PCM connector for the lamp driver circuit

disconnected.

2. Ignition “ON”.
3. Using a DVM, check the voltage at the PCM

connector for the affected lamp driver circuit.

Was the voltage equal to the specified value?

B+

Go to

Step 15

Go to

Step 8

1. Ignition “ON”.
2. Check for battery voltage at the fuse for the affected

lamp circuit.

Was battery voltage available at the fuse?

—

Go to

Step 10

Go to

Step 9

Repair the open circuit between the ignition switch and
the fuse.

Is the action complete?

—

Verify repair

—

1. Ignition “OFF”.
2. Disconnect the PCM connector for the affected

driver terminal.

3. Connect an ohmmeter between a good ground and

the PCM connector for the affected driver.

Did the ohmmeter indicate continuity?

—

Go to

Step 11

Go to

Step 12

Repair the short to ground between the affected
component and its PCM driver terminal.

Is the action complete?

—

Verify repair

—

Repair the open circuit between the fuse and the PCM
driver terminal for the affected circuit.

Is the action complete?

—

Verify repair

—

1. Connect the PCM.
2. Start the engine and let it idle.
3. Backprobe the affected terminal at the PCM with a

DVM.

Was the voltage equal to the specified value?

Go to

Step 15

Go to

Step 14

1. Run the engine at idle.
2. Check for battery voltage at the fuse for the affected

circuit.

Was battery voltage available at the fuse?

—

Go to

Step 10

Go to

Step 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

—

6E–449

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1648 Received incorrect security code

D06R200118

Circuit Description

The PCM decides whether that is an abnomality in the
immobilizer control system. DTC P1648 are recorded by
the PCM when received incorrect security code.

Condition for Setting the DTC

Received incorrect security code.

Action Taken When the DTC Sets

Flashing the SVS lamp.

The engine does not start.

Condition for Clearing the MIL/DTC

Use clear DTC information with Tech 2. (Refer to

the

immobilizer workshop manual.) (ISUZU UES
Immobilizer system)

Diagnostic Aids

Check for the following conditions:

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

Damaged harness-Inspect the wiring harness for
damage, If the harness appears to be OK, disconnect
the PCM and Immobilizer, turn the ignition “ON” and
observe a voltmeter connected to the suspect driver
circuit at the PCM and Immobilizer harnass connector
while moving connectors and wiring harnesses relates
to the SVS lamp.
A change in voltage will indicate the location of the
fault.

DTC P1648-Received incorrect security code

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

system check

Recheck the security code.

Is the action complete?

—

Verify repair

—

Content .. 517 518 519 520 ..