Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
15 MIL NEVER ON
DESCRIPTION
Malfunction indicator light never on
POSSIBLE
CAUSE
• MIL burned out
• Blown fuse
• Open circuit between battery to PCM
• Open between ground and PCM
• Open or short to power between MIL and PCM
• Open printed circuit on instrument cluster
STEP
INSPECTION ACTION
1
Is ROOM fuse burnt? Yes Repair wiring harness and replace fuse.
No Go to next step.
2
Connect NGS tester to DLC.
Access MIL PID.
Turn ignition switch ON.
Does MIL PID read ON?
Yes Go to next step.
No Check for open circuit between PCM and battery or
ground.
3 Is there correct voltage at MIL fuse?
Specification
More than 10.5 V
Yes Go to next step.
No Repair open in wiring harness between fuse block and
ignition switch.
4 Remove MIL bulb.
Is voltage correct on positive side of MIL bulb
socket?
Specification
More than 10.5 V
Yes Go to next step.
No Repair open circuit in wiring harness between fuse block
and MIL bulb socket.
5 Apply 12 volts and ground to MIL bulb.
Does MIL illuminate?
Yes Check for open circuit between MIL and PCM.
If wire harness is okay, replace PCM.
No Replace MIL bulb.
16 HIGH OIL CONSUMPTION/LEAKS
DESCRIPTION
Oil consumption excessive
POSSIBLE
CAUSE
• PCV valve malfunction
• Improper engine oil viscosity
• Improper dipstick
• Engine internal part malfunction
STEP
INSPECTION ACTION
1
Remove and shake PCV valve.
Does PCV valve rattle?
Yes Go to next step.
No Replace PCV valve.
2
Check following:
• External leaks.
• Proper dipstick.
• Proper engine oil viscosity.
Are all items okay?
Yes Check internal engine parts such as valves, valve guides,
valve stem seals, cylinder head drain passage, piston
rings.
No Service as necessary.
Repeat step 2.
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