Mazda MX-6 1998, Workshop Manual

Page: 66 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
STEP
INSPECTION ACTION
16 CHECK VACUUM LINE: MANIFOLD
VACUUM SOURCE TO PRC SOLENOID
VALVE INPUT PORT
• Key off.
• Disconnect and inspect vacuum line
between manifold vacuum source and PRC
solenoid valve input vacuum port for
blockage, kinks or cracks.
• Is vacuum line free of damage?
Yes Vacuum line is okay.
RECONNECT vacuum line to manifold vacuum source,
leave other end of line.
Go to next step.
No Vacuum line is damaged.
SERVICE or REPLACE damaged vacuum line.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
17 CHECK VACUUM SIGNAL: MANIFOLD
VACUUM SOURCE TO PRC SOLENOID
VALVE INPUT
• Key off.
• Connect vacuum gauge at unattached end
of vacuum line.
• Start engine while observing vacuum
gauge display.
• Key off.
•
Was a vacuum signal present?
Yes
PRC solenoid valve normally receives manifold vacuum
signal.
REMOVE vacuum gauge.
RECONNECT all components.
Go to next step.
No REMOVE vacuum gauge.
RECONNECT all components.
Go to step 38.
18
CHECK VACUUM LINE: FUEL PRESSURE
REGULATOR TO PRC SOLENOID VALVE
OUTPUT PORT
• Key off.
• Disconnect and inspect vacuum line
between fuel pressure regulator and PRC
solenoid valve output vacuum port for
blockage, kinks or cracks.
• Is vacuum line free of damage?
Yes Vacuum line is okay.
RECONNECT vacuum line.
Go to next step.
No Vacuum line is damaged.
SERVICE or REPLACE damaged vacuum line.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
19 CHECK FOR PRC SOLENOID VALVE -
VALVE STUCK CLOSED
• Key off.
• Breakout box installed. PCM connected.
• Disconnect vacuum line from PRC solenoid
valve to fuel pressure regulator at fuel
pressure regulator. Install vacuum gauge at
unattached end of vacuum line.
• Disconnect vacuum line from intake
manifold vacuum to PRC solenoid valve at
manifold vacuum source.
Note
• PRC solenoid valve contains normally
open valve. If solenoid is not energized
while vacuum is applied at input port,
vacuum signal will normally be allowed to
pass.
• Install vacuum pump at input port of PRC
solenoid valve and apply -2 7 ------33 kPa
{-2 0 2 ------247 mmHg, - 8 ------10 inHg} of
vacuum to PRC solenoid valve while
observing vacuum gauge.
• Is vacuum signal indicated by vacuum
gauge?
Yes PRC solenoid valve is not stuck closed.
Go to next step.
No The PRC solenoid valve is stuck closed.
REPLACE damaged PRC solenoid valve.
REMOVE vacuum gauge and pump.
RECONNECT all components.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
01-01A-38