Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
STEP INSPECTION
ACTION
6 CHECK FOR INTERMITTENT FAULT IN
HARNESS AND CONNECTOR
• Key off.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc.
• Install breakout box.
• Connect DVOM to Test Pin 67 and Test Pin
71 at breakout box.
• Key on, engine off.
• Observe DVOM display for an indication of
a fault (changing voltage) while performing
the following:
• Lightly tap on purge solenoid valve.
• Wiggle purge solenoid valve connector.
• Grasp the purge solenoid valve vehicle
harness connector and wiggle wires
between the solenoid and PCM.
• Is fault detected?
Yes ISOLATE fault and SERVICE as necessary.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
No
Unable to duplicate and/or identify fault at this time.
Intermittent poor connection or component malfunction
(Repair as necessary.).
Go to ENGINE SYMPTOM TROUBLESHOOTING No.27.
DTC P0446 Evaporative emission control system vent control malfunction
DESCRIPTION
• DTC P0446 indicates an excessive fuel tank pressure (FTP) or vent control malfunction in
Evaporative Emission Control System
[Possible Cause]
• Damaged FTP sensor
• Kinks or blockage in fuel vapor hose/tube
• Constant voltage circuit to FTP sensor open
• Fuel vapor storage canister vent restriction
• Damaged Canister Vent side filter
• Damaged Canister Drain Cut Valve (CDCV)
• Damaged PCM
Warning
Following troubleshooting flow chart contains fuel system diagnosis and repair procedures. Read following
warnings before performing fuel system service:
• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames
away from fuel.
• Fuel line spills and leaks are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel
can also irritate skin and eyes. To prevent this, always complete “BEFORE REPAIR PROCEDURE” and “AFTER
REPAIR PROCEDURE” described in this manual.
D- 0 1 -1 4 BEFORE REPAIR PROCEDURE
D- 0 1 -1 4 AFTER REPAIR PROCEDURE
STEP
INSPECTION
ACTION
1 CHECK FTP SENSOR
• Key on, engine off.
Note
• The FTP V PID should read between 2.50
and 2.70 volts. Start engine if FTP V PID is
equal to or less than 0.33 volt.
Yes INSTALL fuel filler cap only 1/8 turn so that cap initially
clicks by sound or touch.
Go to step 3.
• Access FTP V PID.
• Key on, engine running.
• Idle engine for 3 minutes.
• Loosen fuel filler cap.
• Again, access FTP V PID with NGS tester.
• Is FTP V PID voltage between 2.40 and
2.80 volts?
No
INSTALL fuel filler cap only 1/8 turn so cap initially clicks
by sound or touch.
Go to next step.
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