1998 ISUZU TROOPER fuse

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 ªONº 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 ªON.º
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

Ignition ªON.º

Engine running.

No DTC 1618.

Ignition voltage is above 13.2 volts for 4 seconds.

Output voltage does not equal ignition voltage when
output is ªOFFº or output voltage is not less than 1 volt
when output is ªON.º

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

DTC P1640 can be cleared by using the Tech 2 ªClear
Infoº 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 ªONº 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:
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):

A13 ± ªCheck Engine Lampº

A14 ± SVS (ºCheck Transº)

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 ªshort circuitº 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

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,ºengine ªOFF.º
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?
ÐGo to Step 3Ð
3Check the fuse for the driver circuit that was shown as
faulty.
Was the fuse blown?
ÐGo to Step 4Go to Step 5
41. 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?
ÐVerify repairÐ
5Disconnect the PCM connector for the affected driver
circuit.
Is there any damage to the PCM pin or connector?
ÐGo to Step 6Go to Step 7
6Repair the damaged pin or terminal.
Is the action complete?
ÐVerify repairÐ
7Were either of the lamp circuits for ªCheck Engineº or
ªCheck Trans.º indicated as faulty by the Tech 2?
ÐGo to Step 8Go to Step 14
81. Leave the PCM connector for the lamp driver circuit
disconnected.
2. Ignition ªON.º
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 16Go to Step 9
91. Ignition ªON.º
2. Check for battery voltage at the fuse for the affected
lamp circuit.
Was battery voltage available at the fuse?
ÐGo to Step 11Go to Step 10
10Repair the open circuit between the ignition switch and
the fuse.
Is the action complete?
ÐVerify repairÐ
111. Ignition ªOFF.º
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?
ÐGo to Step 12Go to Step 13
12Repair the short to ground between the affected
component and is PCM driver terminal.
Is the action complete?
ÐVerify repairÐ

6E±261 ENGINE DRIVEABILITY AND EMISSIONS
DTC P1640 ± Driver-1-Input High Voltage

 
StepNo Ye s Value(s) Action
13Repair the open circuit between the fuse and the PCM
driver terminal for the affected circuit.
Is the action complete?
ÐVerify repairÐ
141. 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?
+BGo to Step 16Go to Step 15
151. Run the engine at idle.
2. Check for battery voltage at the fuse for the affected
circuit.
Was battery voltage available at the fuse?
ÐGo to Step 11Go to Step 10
16Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±299 ENGINE DRIVEABILITY AND EMISSIONS
damage, therefore, it is important to use care when
handling and testing electronic components.
NOTE: To prevent possible Electrostatic Discharge
damage, follow these guidelines:

Do not touch the control module connector pins or
soldered components on the control module circuit
board.

Do not open the replacement part package until the
part is ready to be installed.

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

If the part has been handled while sliding across the
seat, or while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.
NOTE: To prevent internal PCM damage, the ignition
must be in the ªOFFº position in order to disconnect or
reconnect power to the PCM (for example: battery cable,
PCM pigtail, PCM fuse, jumper cables, etc.).
IMPORTANT:When replacing the production PCM
with a service PCM, it is important to transfer the
broadcast code and production PCM number to the
service PCM label. This will allow positive identification of
PCM parts throughout the service life of the vehicle. Do
not record this information on the metal PCM cover.
IMPORTANT:The ignition should always be in the
ªOFFº position in order to install or remove the PCM
connectors.
Service of the PCM should normally consist of either re-
placement of the PCM or EEPROM programming. If the
diagnostic procedures call for the PCM to be replaced,
the PCM should be checked first to ensure it is the correct
part. If it is, remove the faulty PCM and install the new
service PCM.
The service PCM EEPROM will not be programmed.
DTC P0601 indicates the check sum error.
Removal Procedure
1. Disconnect the negative battery cable.
2. Block the wheels.
3. Remove the front console assembly.
1. Remove the four screws.
TS23755
2. Remove the transfer shift lever knob by
unscrewing the knob.
3. Move the transmission gear selector out of the
park position.
4. Lift up sharply on the back edge of the assembly.
5. Disconnect the seat heater switch connectors (if
equipped).
6. Disconnect the POWER and WINTER switch
connectors.
7. Lift out the front console assembly.
TS23756

6E±319 ENGINE DRIVEABILITY AND EMISSIONS
Fuel Pump Relay
Removal Procedure
1. Remove the fuse and relay box cover from under the
hood.
2. Consult the diagram on the cover to determine which
is the correct relay.
3. Insert a small screwdriver into the catch slot on the
forward side of the fuel pump relay.

The screwdriver blade will release the catch inside.
T321092
4. Pull the relay straight up and out of the fuse and relay
box.
TS23976R
Installation Procedure
1. Insert the relay into the correct place in the fuse and
relay box with the catch slot facing forward.
2. Press down until the catch engages.

An audible ªclickº will be heard.
T321092
3. Install the fuse and relay box cover.
Fuel Rail Assembly
Removal Procedure
NOTE:

Do not attempt to remove the fuel inlet fitting on the
fuel rail. It is staked in place. Removing the fuel inlet
fitting will result in damage to the fuel rail or the
internal O-ring seal.

Use care when removing the fuel rail assembly in
order to prevent damage to the injector electrical
connector terminals and the injector spray tips.

Fittings should be capped and holes plugged during
servicing to prevent dirt and other contaminants from
entering open lines and passages.

6E±323 ENGINE DRIVEABILITY AND EMISSIONS
11. Connect the fuel filler fuse at the tank.
12. Connect the air breather hose at the tank.
TS23796
13. Fill the fuel tank with fuel.
14. Tighten the fuel filler cap.
15. Connect the negative battery cable.
Throttle Body (TB)
Removal Procedure
1. Disconnect the negative battery cable.
2. Drain the cooling system. Refer to
Cooling System.
3. Remove the accelerator cable assembly. Refer to
Accelerator Cable in Engine Speed Control System..
4. Disconnect the electrical connectors:

Throttle position (TP) sensor.

Idle air control (IAC) solenoid.

Intake air temperature (IAT) sensor. Refer to
Intake Air Temperature Sensor.
035RW023
5. Disconnect the vacuum hose below the air horn.
6. Remove the intake air duct clamp.
7. Disconnect the intake air duct.
8. Disconnect the coolant lines from the throttle body.
9. Remove the bolts from the common chamber.
10. Remove the throttle body from the common chamber.
11. Remove the gasket from the upper intake manifold.
035RW024
12. Remove the IAC. Refer to Idle Air Control (IAC)
Solenoid
.
13. Remove the TP sensor. Refer to
Throttle Position
(TP) Sensor
.
Inspection Procedure
NOTE: Do not use solvent of any type when you clean the
gasket surfaces on the intake manifold and the throttle
body assembly. The gasket surfaces and the throttle
body assembly may be damaged as a result.

If the throttle body gasket needs to be replaced,
remove any gasket material that may be stuck to the
mating surfaces of the manifold.

Do not leave any scratches in the aluminum casting.
Installation Procedure
1. Install the TP sensor. Refer to Throttle Position (TP)
Sensor
.
2. Install the IAC. Refer to
Idle Air Control (IAC)
Solenoid
.
3. Install the gasket on the common chamber.
4. Install the throttle body on the common chamber.

6E±325 ENGINE DRIVEABILITY AND EMISSIONS
Spark Plug Gap Check

Check the gap of all spark plugs before installation.

Use a round wire feeler gauge to ensure an accurate
check.

Plugs installed with the wrong gap can cause poor
engine performance and excessive emissions.
Installation Procedure
NOTE: The plug must thread smoothly into the cylinder
head and be fully seated. Use a thread chaser if
necessary to clean the threads in the cylinder head.
Cross-threading or failure to fully seat the spark plug can
cause plug overheating, exhaust blow-by gas, or thread
damage. Do not overtighten the spark plugs. Over
tightening can cause aluminum threads to strip.
1. Install the spark plug in the engine. Use the
appropriate spark plug socket.
Tighten

Tighten the spark plug to 18 N´m (13 lb ft.).
2. Install the ignition coil and spark plug boot over the
spark plug.
014RW108
3. Secure the ignition coil to the rocker cover with two
screws.
014RW091
4. Connect the electrical connector at the ignition coil.
5. Connect the negative battery cable.
Catalytic Converter
Removal and Installation Procedure
Refer to Engine Exhaust in Engine.
Air Conditioning Relay
Removal Procedure
1. Remove the fuse and relay box cover from under the
hood.
2. Consult the diagram on the cover to determine which
is the correct relay.
3. Insert a small screwdriver into the catch slot on the
forward side of the fuel pump relay.

The screwdriver blade will release the catch inside.
T321092

6E±326
ENGINE DRIVEABILITY AND EMISSIONS
4. Pull the relay straight up and out of the fuse and relay
box.
TS23986
Installation Procedure
1. Insert the relay into the correct place in the fuse and
relay box with the catch slot facing forward.
2. Press down until the catch engages.

An audible ªclickº will be heard.
3. Install the fuse and relay box cover.
TS23986
EVAP Canister Hoses
Service Information
To view the routing of the EVAP canister hoses, refer to
Vehicle Emission Control Information in Diagnosis. Use
6148M or equivalent when you replace the EVAP canister
hoses.
EVAP Canister
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the three hoses from the EVAP canister.
014RW145
3. Remove the retaining two bolts on the mounting
bracket and slide the canister out of mounting
bracket.
014RW146
Inspection Procedure
1. Inspect the hoses for cracks and leaks.
2. Inspect the canister for a damaged case.