Mazda MX-6 1998, Workshop Manual

Page: 96 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
STEP INSPECTION ACTION
2
CHECK CONSTANT VOLTAGE AT FTP
SENSOR VEHICLE HARNESS
CONNECTOR
• Key off.
• Disconnect FTP sensor vehicle harness
connector.
• Key on, engine off.
• Measure voltage between the constant
voltage circuit and FTP sensor ground
circuit at the FTP sensor harness
connector.
• Is constant voltage between 4.0 and 6.0
volts?
Yes Constant voltage is open in FTP sensor.
REPLACE FTP sensor.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
w After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No Constant voltage is out of range.
SERVICE open or short in constant voltage circuit.
3
CHECK FOR RESTRICTION AT CHARCOAL
CANISTER AND CDCV
• Check for kinks or bends in fuel vapor
hoses from fuel tank to the in-line tee and
from tee to both purge solenoid valve and
charcoal canister.
• Disconnect both ends of fuel vapor hose
between charcoal canister and pressure
control valve.
• Check for vacuum bleed on disconnected
fuel vapor hose with vacuum pump. Fuel
vapor hose must not hold vacuum.
• Check for excessive debris in charcoal
canister or restrictions at charcoal canister
atmosphere venting port to canister drain
cut valve (CDCV) (most applications have
CDCV directly attached to charcoal
canister).
• Check for kinks or bends in purge air inlet
tube (larger diameter hose) between CDCV
and atmosphere.
• Is obstruction indicated?
Yes SERVICE as necessary.
RECONNECT all components.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No
Go to next step.
4 CHECK HOSE FROM CANISTER DRAIN
CUT VALVE (CDCV) FILTER PORT TO
ATMOSPHERE
• Disconnect vacuum hose to atmosphere at
CDCV.
Yes
RECONNECT all components.
Go to step 7.
• Install hand-held vacuum pump to CDCV
side of vacuum hose.
• Apply vacuum to vacuum hose.
• Does air flow?
No Go to next step.
5 INSPECTION OF CHECK VALVE
• Remove and inspect check valve for
plugging.
• Is fault detected?
Yes REPLACE check valve.
RECONNECT all components.
RESET PCM completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No Go to next step.
6
INSPECTION OF AIR FILTER
• Remove and inspect air filter for plugging.
•
Is fault detected?
Yes
REPLACE air filter.
RECONNECT all components.
RESET PCM completely clear DTCs.
c
r
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No REPLACE vacuum hose.
RECONNECT all components.
RESET PCM completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
01-01A -68