Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL KL]
27
INTERMITTENT CONCERNS
DESCRIPTION Symptom occurs randomly and is difficult to diagnose
STEP INSPECTION
ACTION
1
Talk to customer and fill out “Check Sheet.”
Review vehicle service history.
Does vehicle have number of previous repairs
and components replaced for certain
symptom?
Yes Go to next step.
No Go to diagnostic chart for symptom.
2 Key on, engine off.
Connect NGS tester to DLC.
Access PIDs based on information from
Symptom Charts.
Lightly tap on component while viewing PID
values. Wiggle and pull each component wire
(Signal, Signal Return and constant voltage, if
applicable) at component.
Wiggle and pull each sensor wire (Signal,
Signal Return and constant voltage, if
applicable) from component back to PCM
connector.
Look for abrupt changes in PID values.
Are any PID values out of range or suddenly
drop out and back into range?
Yes Possible wiring or component problem.
Check each wire for corrosion, bent or loose terminals and
poor wire terminal crimps.
Service as necessary.
Otherwise, replace component.
Verify repair.
No Go to next step.
3
Continue to monitor information from previous
step.
Key on, engine running.
Lightly tap on component while viewing PID
values.
Also wiggle and pull each component wire
(Signal, Signal Return and constant voltage, if
applicable) from component back to PCM
connector.
Look for abrupt changes in PID values.
Are any PID values out of range or suddenly
drop out and back into range?
Yes Possible wiring or component problem.
Check each wire for corrosion, bent or loose terminals and
poor wire terminal crimps.
Service as necessary.
Otherwise, replace component.
Verify repair.
No Go to next step.
4 Continue to monitor PIDs listed in previous
step.
With engine still running, continue to
individually water soak wires and connectors
which are related to monitor items.
Look for abrupt changes in PID values or
engine running conditions.
Are any PID values out of range or suddenly
drop out and back into range or was there
noticeable engine misfire/stumble?
Yes Fault area is identified. If fault occurred while spraying on
component, replace part and verify repair. If unable to
verify, reinstall original part.
If fault occurred while spraying wiring, check each circuit
wire for corrosion, bent or loose terminals and poor wire
terminal crimps.
Service as necessary.
If fault occurred while spraying vacuum line.
Service as necessary.
Verify repair.
No Go to next step.
5 Continue to monitor information from previous
step.
Drive vehicle under “Check Sheet” condition.
Look for abrupt changes in PID values.
Are any PID values out of range or suddenly
drop out and back into range?
Yes
Possible wiring or component problem.
Check each wire for corrosion, bent or loose terminals and
poor wire terminal crimps.
Service as necessary.
Otherwise, replace component.
Verify repair.
No
Reconfirm “Check Sheet” and reselect related PIDs.
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