Mazda MX-6 1998, Workshop Manual

Page: 247 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION ACTION
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.
vr 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 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.
20
CHECK FOR PRC SOLENOID VALVE
STUCK OPEN
• Key off.
• Breakout box installed. PCM connected.
• Installed vacuum gauge at output port of
PRC solenoid valve.
• Vacuum pump installed at input port of
PRC solenoid valve.
• Apply -2 7 ------33 kPa {-2 0 3 ------247 mmHg,
- 8 ------10 inHg} of vacuum to PRC solenoid
valve input port.
• Key on.
• Momentarily jum per Test Pin 1
9 to Test Pin
103 at breakout box and observe vacuum
gauge.
Note
• PRC solenoid valve contains normally
open valve. If solenoid is energized while
vacuum is applied at input port, vacuum
signal will normally not be allowed to pass
because solenoid valve will be closed.
• Key off.
•
Did vacuum gauge reading drop from
- 2 7 ------ 33 kPa {-2 0 3 ------ 247 mmHg, - 8 —
-1 0 InHg} to 0 ------ 3.3 kPa {0 ------ 25
mmHg, 0 ------ 1 InHg} when Pin 19 was
jumpered to Pin 103?
Yes
PRC solenoid valve is not stuck open.
REMOVE vacuum gauge and pump.
RECONNECT all components.
Go to next step.
No PRC solenoid valve is stuck open.
REPLACE damaged PRC solenoid valve.
REMOVE vacuum gauge and pump.
RECONNECT all components.
RESET PCM to completely clear DTCs.
et
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
01-01B-41