Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 324

6E–326

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0445 EVAP Purge Control Circuit Short

060RY00398

Circuit Description

The canister purge solenoid valve is controlled by the
Power Train Control Module (PCM). The PCM monitors
vacuum level via the fuel tank pressure sensor input.
At an appropriate time, the EVAP canister purge solenoid
is “ON,” allowing engine vacuum to draw a small vacuum
on the entire evaporative emissions system.

Conditions for setting the DTC

The Ignition is “ON”.

Engine is running.

System voltage is between 11.5 volts and 16 volts.

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 in the Failure Records data only.

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 P0445 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.

DTC P0445 can be cleared using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

An intermittent may be caused by the following:

Poor connections.

Misrouted harness.

Rubbed through wire insulation.

Broken wire inside the insulation.

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, observe the
EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to the
sensor.
A change in the display will indicate the location of
the fault. If DTC P0445 cannot be duplicated, the
information included in the Failure Records data can
be useful in determined vehicle mileage since the
DTC was last set.

If it is determined that the DTC occurs intermittently,
performing the DTC P0445 Diagnostic Chart may
isolate the cause of the fault.

6E–327

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0445 EVAP Purge Control Circuit Short

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

1. Install the Tech 2.
2. Ignition is “ON”,
3. Observe the EVAP purge solenoid reading on the

Tech 2.

Is the EVAP purge solenoid reading near the specified
value?

Refer to

Diagnostic

Aids

Go to

Step 3

Check the signal circuit for canister purge solenoid
valve.

1. Ignition is “OFF”.
2. Disconnect the canister purge solenoid valve.
3. Disconnect the PCM.
4. Check the circuit between EVAP purge solenoid

connector and PCM connector.

Is the problem found?

—

Go to

Step 4

Go to

Step 5

Repair the circuit as necessary. Is the action complete?

—

Verify repair

—

Check the canister purge solenoid valve.
Using a DVM, measure resistance for purge solenoid
valve connector terminal.

Is the purge solenoid valve resistance within the
specified values?

25–30 (at

F{20

C})

Go to

Step 7

Go to

Step 6

Replace the canister purge solenoid valve.

Is the action complete?

—

Verify repair

—

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 action complete?

—

Verify repair

—

6E–328

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P0446 EVAP Canister Vent Control Malfunction

060RY00398

Circuit Description

The evaporative system includes the following
components:

Fuel tank

EVAP canister vent solenoid

Fuel tank (vapor) pressure sensor

Fuel pipes and hoses

Vapor lines

Fuel cap

Evaporative emissions canister

Purge lines

EVAP canister purge solenoid

An incorrect fuel tank pressure sensor signal is detected
by monitoring fuel tank pressure when the key is first
turned “ON” during a cold start. If the fuel tank pressure
signal is out of range, DTC P0446 will set. A restricted or
blocked EVAP vent path is detected by monitoring fuel
tank pressure during normal operation (EVAP canister
vent solenoid open, EVAP canister purge solenoid
normal). With the EVAP canister vent solenoid open,
vacuum level in the system should be very low unless the
vent path is blocked. A blockage can be caused by the
following condition:

Faulty EVAP canister vent solenoid (stuck closed).

Plugged, kinked or pinched vent hose.

Shorted EVAP canister vent solenoid driver circuit.

Plugged evaporative canister.

If any of these conditions are present, DTC P0446 will set.

Conditions for Setting the DTC

No TP sensor, ECT sensor, Tank pressure sensor, IAT
sensor, or MAP sensor DTCs set.

Start-up engine coolant temperature and start-up
intake air temperature are more than 4

C (39

F) but

less than 34

C(93

F).

Start-up engine coolant temperature is not more than
7

C (13

F) greater than start-up intake air

temperature.

Fuel tank level is between 15% and 85%.

BARO is greater than 70 kPa.

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

The PCM will store conditions which were present
when the DTC set as Freeze Frame and Failure
Records 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 P0446 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

6E–329

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0446 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 to the
EVAP canister vent solenoid, EVAP canister purge
solenoid and the fuel tank pressure sensor for an
intermittent open or short circuit.

Kinked, pinched, or plugged vent hose–Verify that the
vent hose between the EVAP canister and EVAP
canister vent solenoid is not restricted.
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.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If a vent solenoid electrical fault is present, the purge

system will not operate correctly. Repairing the
electrical fault will very likely correct the condition
that set DTC P0446.

3. Checks the fuel tank pressure sensor at ambient

pressure.

4. Verifies that the fuel tank pressure sensor accurately

reacts to EVAP system pressure changes.

6. Checks for a blocked EVAP canister.

DTC P0446– EVAP Canister Vent Control Malfunction

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 “ON.”
2. Capture Failure Records data for DTC P0446 and

clear DTCs.

3. Ignition “OFF.”
4. Remove the fuel cap.
5. Ignition “ON.”
6. Observe “Fuel Tank Pressure” on the Tech 2.

Does Tech 2 indicate “Fuel Tank Pressure” at the
specified value?

1.51V

Go to

Step 3

Go to

Fuel

Tank

Pressure

System

IMPORTANT: Before continuing with diagnosis, zero
the EVAP pressure and vacuum gauges on the EVAP
pressure/purge cart J 41413 (refer to tool operating
instructions).

7. Replace the fuel cap.
8. Using the Tech 2, command the EVAP vent

solenoid “ON” (closed).

9. Connect the EVAP pressure/purge cart J 41413 to

the EVAP service port.

10.Using the EVAP pressure/purge cart J 41413,

pressurize the EVAP system to the specified value.

11. Observe “Fuel Tank Pressure” on the Tech 2.

Does Tech 2 indicate “Fuel Tank Pressure” at the
specified value?

1.52 – 1.69V

Go to

Step 4

Go to

Fuel

Tank

Pressure

System

1. Maintain the EVAP pressure at 5 in. at H

2. Using Tech 2, command the EVAP vent solenoid

“OFF” (open) while observing the EVAP pressure
gauge on the cart J 41413.

Does the EVAP pressure return to the specified value
within 5 seconds?

0 in. H

Refer to

Diagnostic

Aids

Go to

Step 5

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