6E2–146
6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
D
Leaking injector – Refer to
Fuel System Diagnosis.
D
Evaporative emissions (EVAP) system – Check the
canister for fuel saturation. If the canister is full of fuel,
check EVAP control system components and hoses.
Refer to
Evaporative Emission (EVAP) Control
System.
D
MAF sensor – The system can go rich if the MAF
sensor signal indicates an engine airflow
measurement that is not correct Disconnect the MAF
sensor to see if rich condition is corrected. If so,
replace MAF sensor.
D
Check for leaking fuel pressure regulator diaphragm by
checking vacuum line to regulator for the presence of
fuel. There should be no fuel in the vacuum line.
D
TP sensor – An intermittent TP sensor output will
cause the system to go rich, due to a false indication
of the engine accelerating.
D
Shorted Heated Oxygen Sensor (HO2S)– If the HO2S
is internally shorted, the HO2S voltage displayed on
the Tech 2 will be over 1 volt. Try disconnecting the
affected HO2S with the key “ON,” engine “OFF.” If the
displayed HO2S voltage changes from over 1000 mV
to around 450 mV, replace the HO2S. Silicon
contamination of the HO2S can cause a high HO2S
voltage to be indicated. This condition is indicated by
powdery white deposit on the portion of the HO2S
exposed to the exhaust stream. If contamination is
noticed, replace the affected HO2S.
D
Open HO2S Signal Circuit of Faulty HO2S– A poor
connection or open in the HO2S signal circuit can
cause the DTC to set during deceleration fuel mode.
An HO2S which is faulty and not allowing a full voltage
switch between the rich and lean thresholds can also
cause the condition. Operate the vehicle while
monitoring the HO2S voltage with a Tech 2. If the
HO2S is voltage limited within a range between 300
mV to 600 mV, check the HO2S signal circuit wiring
and associated terminal connections.
D
If none of the above conditions are present, replace the
affected HO2S.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. DTC P0152 failing during deceleration fuel cutoff
mode operation may indicate a condition described
in the “Diagnostic Aids” above. If the DTC P0152
test passes while the Failure Records conditions are
being duplicated, an intermittent condition is
indicated.
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.