Isuzu Trooper (1998-2002 year). Manual - part 520

6E–450

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble code (DTC)

P1649 Security code & security key not programmed

D06R200118

Circuit Description

The PCM decides whether that is an abnomality in the
immobilizer control system. DTC P1649 are recorded by
the PCM when security code & secret key not
programmed.

Condition for Setting the DTC

Security code & secret key not programmed.

Action Taken When the DTC Sets

Flashing the SVS lamp.

The engine does not start.

In case replacement PCM/ECM, Action
Taken When the DTC Sets

Flashing the MIL.

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.

6E–451

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1649 Recurity code & secret key not programmed

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

system check

Using the Tech 2 system selection menu, select Body
function.

Does the Tech 2 display B**** appear?

—

Refer

“Immobilize

r workshop

manual”

Go to

Step 3

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures, and immobilizer system workshop
manual.

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?

—

Go to

Step 4

—

Does the Tech 2 display P1649 appear?

—

Go to

Step 3

Verify repair

6E–452

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1650 Quad Driver Module “A” Fault

Circuit Description

The Quad Driver Module (QDMs) are used by the
powertrain control module (PCM) to turn “ON”
current–driven devices that are needed to control two
engine functions. The PCM monitors open or short circuit
of either of Canister Control Purge (CCP) Vent solenoid or
Variable Intake Manifold (VIM).

Conditions for Setting the DTC

Ignition “ON”.

Engine running.

Ignition voltage.

Output voltage does not equal voltage and is not less
than 1 volt when out put is “ON”.

Above conditions occur for at least 0.5 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

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.

A history DTC P1650 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1650 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 relates 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: canister
purge solenoid, fuel level sensor. An open ignition feed
circuit at any of these components will cause DTC
P1650 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.

The following PCM pins are controlled by
Quad driver modules (QDMs):

S74 – VIM

S48 – Canister control purge

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
4. The Tech 2 Driver Module Status indicates the PCM

pin that is affected.

9.The Tech 2 may indicate “short circuit” even when the

problem is an open circuit. The cause of an open
circuit may be in the component itself.

11.A short to ground on the ignition side of the

component will blow the fuse. Since the fuse was
checked in Step 2, a short to ground would be
between the affected component and the PCM.

6E–453

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1650 – Quad Driver Module (QDM) Fault

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

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

—

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