Purge Flow System Circuit - Mazda B-Series 1997 Workshop Manual

ON-BOARD DIAGNOSIS SYSTEM
1
Symptom
Diagnostic trouble code
No. PI443
Vacuum supply malfunct~on, or evaporatlve emlsslon system malfunct~on, or purge flow
sensor clrcurt malfunctlon
p p
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7
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INSPECTION ACTION
PURGE FLOW SYSTEM CIRCUIT
Key ON, engine running.
Access PF PID.
Does PF PID fluctuate around 2.50 volts or 1 . O O volt in
one minute?
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Yes For PF PID voltage from 2.30 to 2.60:
Go to step 7.
For PF PID voltage from 0.90 to 1.1 0:
Go to step 6.
Go to next step.
1
Check for cracks or other damage to canister.
Is canister cracked or damaged?
Remove fuel vapor hose between fuel tank and canister.
Install a hand-held pressure pump w~th gauge to open end
of fuel vapor hose.
Apply 1.0 ~n-Hg (0.5 psi) maxlmum pressure to hose wlth
pressure pump.
Is fuel tank-to-carbon canlster system holding a constant
pressure?
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4 Check for fuel tank damage.
Is fault lndlcated?
Yes Replace can~ster and go to step 15.
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No Go to next step.
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Yes
Check for poss~ble blockage in fuel vapor
hose between tank and canister.
Go to step 15.
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No Go to next step.
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Yes Repa~r or replace as necessary.
Go to step 15.
No Go to next steD
Key OFF.
,
Yes Go to next step.
Disconnect fuel vapor hose between canister and EVAP
canister purge solenoid at both ends.
Plug one end of hose and ~nstall a vacuum pump at
remaining end. No Replace hose and go to step 15.
Apply 16 in-Hg of vacuum to hose.
Does hose hold vacuum applied for at least 15 seconds?
Key OFF
Dlsconnect vacuum hose at both ends of EVAP canlster
purge solenold
Install hand-held vacuum pump to Intake man~fold vacuum
,
s ~ d e of soleno~d.
D~sconnect solenold connector
Apply
16
~n-Hg
(53
kPa) of vacuum to solenold
Does solenold hold vacuum for 20 seconds7
Yes Go to next step.
No Replace solenoid.
Go to step 15.
7
1
Reconnect solenoid connector.
Apply 16 in-Hg (53 kPa) of vacuum to solenold
Key ON, engine off.
Access on scan tool or NGS.
Yes Dlsconnect vacuum pump.
Inspect fuel vapor hose between can~ster and
solenold for blockage or k~nks
If OK, qo to next step.
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i
Does solenold open and vacuum readlng on pump drop
No Check solenold,
1
when command~ng output on7
Go to steD 15.
Key OFF.
Reconnect EVAP canister purge solenoid connector and
vacuum hose.
Disconnect vacuum hose of intake manifold vacuum side
of solenoid.
Start engine and place thumb on open end of vacuum
hose at solenoid.
Is vacuum present at vacuum hose opening?
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Key OFF.
Disconnect vacuum hose between intake manifold and
purge flow sensor from sensor and connect hand-held
vacuum port to purge flow sensor opening port.
Disconnect vacuum hose between EVAP canister purge
solenoid and purge flow sensor from solenoid and plug
hose.
Apply 4.1 in-Hg (1 3.6 kPa) of vacuum to sensor.
Does sensor bleed off all vacuum in less than 2.5
seconds?
Yes Go to next step
No Check vacuum hoses for proper routrng,
leaks, cracks, blockage and klnks.
Repa~r or replace the evaporatlve emlsslon
canlster purge solenold valve and/or vacuum
hoses.
Go to step 15.
Yes Replace purge flow sensor
Go to step 15.
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No Connect all vacuum hoses
Go to step 10.
FT-I 34