Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1300

6E1–276

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0446 EVAPORATIVE EMISSION (EVAP)

CONTROL SYSTEM VENT CONTROL CIRCUIT MALFUNCTION

060R100040

Circuit Description

The evaporative system includes the following
components:

D

Fuel tank.

D

EVAP vent solenoid.

D

Fuel tank pressure sensor.

D

Fuel pipes and hoses.

D

Fuel vapor lines.

D

Fuel cap.

D

EVAP canister.

D

Purge lines.

D

EVAP canister purge valve.

D

EVAP service port.

The evaporative emission system is checked by applying
vacuum to the EVAP system and monitoring for a vacuum
decay.  The PCM monitors the vacuum level through the
fuel tank pressure sensor signal.
At an appropriate time, the EVAP canister purge valve
and the EVAP vent solenoid are turned ON, allowing the
engine to draw a small vacuum on the entire evaporative
emission system.  After the desired vacuum level has
been achieved, the EVAP canister purge valve is turned
OFF, sealing the system.
A restricted or blocked EVAP canister vent path is
detected by drawing a vacuum on the EVAP system,
turning OFF the EVAP vent solenoid and the EVAP

canister purge valve (EVAP vent solenoid Open, EVAP
purge PWM 0%) and monitoring the fuel tank vacuum
sensor input.  With the EVAP vent solenoid open, any
vacuum in the system should decrease quickly unless the
vent path is blocked. A blockage can be caused by the
following conditions:

D

Faulty EVAP vent solenoid (stuck closed).

D

Plugged, kinked or pinched vent hose.

D

Shorted EVAP vent solenoid driver circuit.

D

Plugged evaporative canister.

If any of these conditions are present, Diagnostic Trouble
Code P0446 will set.  DTC P0446 is a type B code.

Conditions for Setting the DTC

D

The BARO is greater than 72.3 kPa.

D

No: MAP, TPS, IAT, ECT, EGR, EVAP Purge Solenoid,
EVAP Vent Solenoid, VSS or System Voltage
Diagnostic Trouble Codes.

D

IAT and ECT at startup are between 4.2

°

C(40

°

F) and

35

°

C (95

°

F).

D

The difference between IAT and ECT at startup is less
than 6.75

°

C (12.2

°

F).

D

The Fuel Tank Level Sensor reads between 15% and
85%.

The above conditions are met, and the following condition
is met once while ignition cycle:

6E1–277

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

D

Fuel Tank vacuum is greater than 20 cm (8 inches) of
water while 2 seconds.

Action Taken When the DTC Sets

D

The Malfunction Indicator Lamp (MIL) will illuminate.

D

The PCM will records operating conditions at the time
the diagnostic fails.  The Freeze Frame and Failure
Records buffers will store this information.

D

A history Diagnostic Trouble Code is stored.

Conditions for Clearing the MIL/DTC

D

The MIL will turn off after 3 consecutive ignition cycles
in which the diagnostic runs without a fault.

D

A history DTC will clear after 40 consecutive warm up
cycles without a fault.

D

A Tech 2 can clear the DTC’s.

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

The Fuel Pressure Sensor shares a 5 Volt reference
with the MAP sensor.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.

D

The Fuel Pressure Sensor share a ground with the
ECT sensor, the TP sensor the CKP, the CMP, and
automatic transmission temperature sensor.

D

Damaged harness: Inspect the wiring harness to the
EVAP vent solenoid and the fuel tank pressure sensor
for shorts to ground, shorts to battery positive, and
open circuits.

D

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

Check for charcoal particles.  Refer to Carbon Particles
Removal from EVAP System before starting repairs.
Reviewing the Fail Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that causes the Diagnostic Trouble Code 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:
1. The Powertrain OBD System Check prompts the

technician to complete some basic checks and store
the freeze frame and failure records data on the
Tech 2 if applicable.  This creates an electronic copy
of the data taken when the malfunction occurs.  This
may assist in diagnosing the condition.

3. If a vent solenoid electrical malfunction is present,

the purge system will not operate correctly.
Repairing the electrical malfunction will very likely
correct the condition that set Diagnostic Trouble
Code P0446.

4. Checks the fuel tank pressure sensor at ambient

pressure.

6. Forces the fuel tank pressure sensor to re–zero.

7. Verifies that the fuel tank pressure sensor

accurately reacts to EVAP system pressure
changes.

9. Checks for a blocked EVAP canister.

13. Duplicates the Powertrain On–Board Diagnostic

test.

6E1–278

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0446 EVAP Control System Vent Control Circuit Malfunction

 

Step

Action

Value(s)

Yes

No

1

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

—

Go to Step  2 

Go to

Powertrain

OBD System

Check 

2

Is Diagnostic Trouble Code P0461, P0462, or P0463
also set?

—

Go to

Applicable
DTC chart

Go to Step  3 

3

1. Install a Tech 2.
2. Command the EVAP canister purge valve and vent

solenoid ON and OFF with the Tech 2?

Does the purge valve and vent solenoid click ON and
OFF? (if no, start with the diagnosis chart for other
sensors in the circuit and see if 5V returns.)

–

Go to Step  4 

Go to PCM

Outputs

Diagnosis

4

1. Turn the ignition switch OFF.
2. Remove the fuel cap.
3. Turn the ignition switch ON.

Is the Fuel Tank Pressure at the specified value?

1.51V

Go to Step  7 

Go to Step  5 

5

Has the battery been disconnected?

—

Go to EVAP

Control

System

Diagnosis 

Go to Step  6 

6

Disconnect the battery, wait 30 seconds, then
reconnect the battery.

Is the action complete?

—

Go to Step  4 

—

7

IMPORTANT: Before continuing with this diagnosis,
zero the EVAP Pressure and Vacuum Gauges on the
EVAP pressure/purge cart J41413. Also read the
temperature variation instruction card. (Refer to tool
operating instructions).

1. Reinstall the fuel cap.
2. Using the Tech 2, command the EVAP vent solenoid

ON (closed).

3. Connect the EVAP pressure/purge cart J41413 to

the EVAP service port.

4. Pressurize the EVAP system to the specified value

using the EVAP pressure/purge cart J41413
(monitor the pressure using the gauge on the cart
with the switch in the ”HOLD” position.

5. Observe the Fuel Tank Pressure on the Tech 2.

Is the Fuel Tank Pressure at the specified value?

1.52 – 1.69V

Go to Step  8 

Go to EVAP

Control

System

Diagnosis 

8

1. Maintain the specified EVAP pressure.
2. Using the Tech 2, command the EVAP vent solenoid

OFF (open) while observing the EVAP pressure
gauge on the cart J41413.

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

0 in. H2O

Refer to

Diagnostic

Aids 

Go to Step  9 

6E1–279

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0446 EVAP Control System Vent Control Circuit Malfunction

  (Cont'd)

Step

No

Yes

Value(s)

Action

9

1. Disconnect the large vent hose (marked air) from

the EVAP canister.

2. Switch the rotary switch on the cart J41413 to

PURGE.

3. Start  the engine and allow the engine to reach

operating temperature.

4. Observe the vacuum gauge for 5 seconds while

holding the engine speed at the specified value.

Does the vacuum remain below the specified value?

30 in. H2O

2500 RPM

Go to Step

10 

Go to Step

12 

10

1. Inspect the EVAP vent hose between the EVAP

canister and the EVAP vent solenoid for being
kinked, pinched, or other wise blocked.

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

Was a problem found?

—

Go to Step

13 

Go to Step

11 

11

Replace the EVAP vent solenoid. Refer to Diagnostic
Aids

Is the action complete?

—

Go to Step

13 

—

12

Replace the EVAP canister. Refer to EVAP Canister
Replacement.

Is the action complete?

—

Go to Step

13 

—

13

1. Using the Tech 2, command the EVAP vent solenoid

ON (closed).

2. Pressurize the EVAP system to the specified value.
3. Switch the rotary switch on the cart J41413 to

HOLD.

4. Using the Tech 2, command the EVAP vent solenoid

OFF (open) while observing the EVAP pressure
gauge on the cart J41413.

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

1.51V

System OK

Go to Step  3