Isuzu Rodeo UE. Manual - part 414

6E2–411

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1618 Serial Peripheral Interface (SPI) PCM

Interprocessor Communication Error

Circuit Description

The serial peripheral interface (SPI) communication is
used internally by the PCM to send messages between
the engine processor and the automatic transmission
processor. Included in each message sent between the
two-processors is a checksum of the message. Both the
engine processor and automatic transmission processor
will compare this check sum value with the calculated
value. If the checksums don’t match, the processor will
view the new data as being corrupted and ignore the
values. The processor will then use the previous
message. The receiving processor will then send a
message to the sending processor informing it that it’s
last message was corrupted.

Conditions for Setting the DTC

Battery voltage is above 9.0 V for 2 seconds.

The PCM detects an internal program fault (check sum
of data communications error).

Check sum fault present for 3 out 6 seconds.

No TCM resets for 2 seconds.

Action Taken When the DTC Sets

The PCM will flash the “Check Trans” lamp the first
time the fault is detected.

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

The automatic transmission will operate in the “safety
mode” to protect the mechanical parts of the
transmission. Shift quality and/or gear changes may
not be normal.

Conditions for Clearing the MIL/DTC

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

A history DTC P1618 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1618 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

DTC P1618 – Serial Peripheral Interface (SPI) PCM Interprocessor

Communication Error

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Is the EEPROM calibration the latest version
available?

—

Go to

Step 4

Go to

Step 3

Reprogram the PCM with the latest available
calibrations.

Does DTC 1618 re-appear when the

OBD System

Check is repeated?

—

Go to

Step 4

Repair

completed

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

—

6E2–412

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1625 PCM Unexpected Reset

Circuit Description

The powertrain control module (PCM) monitors
unexpected PCM reset. This will not turn on MIL light on,
only records code DTC P1625.

Conditions for Setting the DTC

Clock or COP (Computer Operating Properly) reset.

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 P1625 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1625 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:

P1625 alone stored does not need diagnosis. Clear
DTC code.

DTC P1625 – PCM Unexpected Reset

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to

OBD

System

Check

1. Ignition is “ON”.
2. Install the Tech 2.
3. Start the engine at let it Idle.
4. On the Tech 2, select “DTC info”.

Does the Tech 2 indicate DTC P1625 failed?

—

Go to

Step 3

Go to

Diagnostic

Aids

1. Ignition is “ON”.
2. Clear DTC P1625 by using the Tech 2 “Clear Info”.
3. Start the engine at let it Idle.
4. On the Tech 2, select “DTC info”.

Does the Tech 2 indicate DTC P1625 failed?

—

Go to

Step 4

Go to

Diagnostic

Aids

1. Check for aftermarket electronics, such as

transceiver, stereos, and anti theft devices. May
radiate EMI into the control system if they are
improperly installed. (This may cause a false sensor
reading and turn on the MIL.)

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

—

6E2–413

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1640 Output Driver Module (ODM) “A” Fault

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 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 check. 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
output driver modules (ODMs):

A13 – MIL (Check Engine)

A14 – Check T/M or Up-Shift

A15 – EVAP Canister Purge

A16 – Band Apply (4L30E)

B14 – A/C Clutch

B15 – Low Fuel Lamp

B16 – CCP Solenoid and VIM

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.

DTC P1640 –Output Driver Module (ODM) “A” 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

—

1. 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

6E2–414

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1640 –Output Driver Module (ODM) “A” Fault

(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?

B+

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

—

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