Opel Frontera UBS. Manual - part 1223

6E–258

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

D

Clock or COP reset.

Action Taken When the DTC Sets

D

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

D

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

D

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:

D

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

6E–259

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1640 Driver-1-Input High Voltage

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 fault.  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

D

Ignition “ON.”

D

Engine running.

D

No DTC 1618.

D

Ignition voltage is above 13.2 volts for 4 seconds.

D

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

D

Above conditions occur for at least 1 second.

Action Taken When the DTC Sets

D

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

D

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

D

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:

D

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.

D

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.

D

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.
The following PCM pins are controlled by output driver
modules (ODMs):

D

A13 – “Check Engine Lamp”

D

A14 – SVS (”Check Trans”)

D

B14 – A/C Clutch

Test Description

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

pin that is affected.

11. 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-lamp,
purge, solenoid, or A/C compressor relay.

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

component will blow the fuse.  Since the fuse was
checked in Step 4, a short to ground would be
between the affected component and the PCM.

6E–260

ENGINE DRIVEABILITY AND EMISSIONS

DTC P1640 – Driver-1-Input High Voltage

 

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

1. Ignition “ON,”engine “OFF.”
2. Install the Tech 2.
3. Review and record Tech 2 Failure Records data.
4. Operate the vehicle within Failure Records

conditions as noted.

5. Use the Tech 2 to indicate DTC P1640.

Does the Tech 2 indicate DTC P1640?

—

Go to 

Step 3

—

3

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

Was the fuse blown?

—

Go to 

Step 4

Go to 

Step 5

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

—

5

Disconnect the PCM connector for the affected driver
circuit.

Is there any damage to the PCM pin or connector?

—

Go to 

Step 6

Go to 

Step 7

6

Repair the damaged pin or terminal.

Is the action complete?

—

Verify repair

—

7

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

—

Go to 

Step 8

Go to 

Step 14

8

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 16

Go to 

Step 9

9

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 11

Go to 

Step 10

10

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

Is the action complete?

—

Verify repair

—

11

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 12

Go to 

Step 13

12

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

Is the action complete?

—

Verify repair

—

6E–261

ENGINE DRIVEABILITY AND EMISSIONS

DTC P1640 – Driver-1-Input High Voltage

  (Cont'd)

Step

No

Yes

Value(s)

Action

13

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

Is the action complete?

—

Verify repair

—

14

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 16

Go to 

Step 15

15

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 11

Go to 

Step 10

16

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed.  Refer to 

UBS 98model year Immobilizer

Workshop Manual.

Is the action complete?

—

Verify repair

—