Isuzu 1999 RODEO Workshop Manual page 968

Diagnostic Aids
Check for the following conditions:
f 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.
f The Fuel Pressure Sensor shares a 5 Volt reference
with the MAP sensor and TP sensor.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.
f The Fuel Pressure Sensor share a ground with the
MAP sensor and the TP sensor.
f Damaged harness – Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive,
and open circuits. If the harness appears to be OK,
observe the EVAP vacuum switch 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.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
DTC P1441 – EVAP System Flow During Non-Purge
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Ignition "OFF."
2. Remove the fuel filler cap.
3. Ignition "ON." Observe "Fuel Tank Pressure" on the
Tech 2.
Is "Fuel Tank Pressure" at the specified value?
3 1. Re–install the fuel filler cap.
2. Using the Tech 2, command the EVAP Vent
Solenoid Valve "ON" (Closed).
3. Disconnect the canister side rubber hose end that
hose is connected between the Purge Solenoid
Valve and Canister.
IMPORTANT: Before continuing with the diagnosis,
zero the EVAP pressure and vacuum gauges on EVAP
pressure / purge cart J41413 (refer to the tool operating
instructions).
And then monitor the fuel tank inner pressure using the
Tech 2.
Does the fuel tank pressure hold the specified value?
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
Action
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. The canister purge vacuum switch is normally
closed when no vacuum (purge) is present. With the
ignition ON and the engine OFF, there shouldn't be
any vacuum (purge) present in the EVAP system.
3. Determines if the PCM is able to control the EVAP
purge solenoid valve.
4. Determines if the DTC will set under the conditions
present when the DTC was originally stored. If not,
the fault is intermittent.
5. Checks for a grounded EVAP purge solenoid driver
circuit, a faulty EVAP vacuum switch, or a leaking
EVAP purge solenoid valve.
Value(s)
Go to Step 2
—
Go to Step 3
1.51 V
1.52 - 1.60 V Go to Step 4
6E1–341
Yes No
Go to OBD
System
Check
Go to P0452
or P0453
Go to Step 6