Catalyst Monitoring System; Evaporative Emission (Evap) Canister Purge Solenoid - Mazda B-Series 1997 Workshop Manual

FT
ON-BOARD DIAGNOSIS SYSTEM
Diagnostic trouble
I
CATALYST MONITORING SYSTEM
code No. PO420
I
Catalvst efficiencv below threshold.
INSPECTION
1
ACTION
Are any DTCs recorded other than P0420?
Yes
1
Go to Diagnostic Trouble Code chart and
1
address other DTCs first.
No
1
Go to next step.
Key OFF.
I
yes
I
Repair or replace connector,
Does the rear H02S sensor connector or PCM connector
Go to s t e ~ 4.
Is fuel pressure OK?
have a poor connection or is it improperly routed?
I
No
1
Go to next step.
No Repair the fuel delivery system.
1
GO to next step.
1
Yes Check the exhaust system for leaks or
Perform After Repair Procedure to ensure customer's concern has been resolved.
-
page FT-154
~
1
Not :
Complete spark timing check before proceeding with this pinpoint test. Spark timing
r tard d below specification may increase exhaust gas temperature and decrease
catalyst efficiency over time.
Be sur customer has not:
1)
Refueled vehicle with lead gasoline.
2) Experienced high engine oil consumption.
Internal deterioration of a catalytic converter is usually caused by abnormal engine
op ration upstream of catalyst.
restrictions.
0-8
page FT-156
Go to next stem
1
Diagnostic trouble
1
EVAPORATIVE EMISSION (EVAP) CANISTER PURGE SOLENOID
code No. PO443
Symptom EVAP canister purge solenoid circuit voltage high or low, or solenoid or valve
malfunction.
I
STEP
1
INSPECTION
1
ACTION
I
Is DTC PO443 present only in Continuous Memory? Yes
No
Go to step 8.
Go to next step.
Does EVAP canister purge solenoid connector or PCM
,
Yes
I
Repair or replace connector.
connector have a poor connection?
3
and solenoid casing.
Measure resistance between VPWR PIN at solenoid and
No Replace solenoid.
solenoid casing.
Go to step 9.
Are both resistance readings greater than 90 ohms?
I
Go to step 9.
No Go to next steD.
4
Key
OFF.
1
Yes
,
Go to next step.
Key OFF.
Disconnect EVAP canister purge solenoid connector.
Repair open in VPWR circuit.
Go to step 9.
Disconnect EVAP canister purge solenoid connector.
Key ON, engine off.
Is voltage between VPWR at solenoid connector and
battery ground terminal greater than 10.5 volts?
,
Is resistance between 30 and 90 ohms between EVAP
I
SIG and VPWR pins at solenoid?
No
Yes
/
Go to next step.
-
No
- -
~~
Replace solenoid.
Go to step 9.
5
/
Measure resistance between EVAP SIG pin at solenoid
Yes
,
Go to next step.