Mazda MX-6 1998, Workshop Manual

Page: 267 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION ACTION
2 CHECK FOR HEATED OXYGEN SENSOR
MONITOR DTC
Note
• Incorrect heated oxygen sensor signal
Input (e.g. rich/lean input signal when
engine is operating under lean/rich
conditions) may cause an abnormal
temperature increase in catalyst.
Note
• Non-California applications will not have an
active Heated Oxygen Sensor Monitor. As
result, Catalyst Efficiency Monitor DTC can
be generated for rear heated oxygen
sensor concern. To check for heated
oxygen sensor concerns go to heated
oxygen sensor inspection. If any
repairactions are necessary procedure, run
key on engine running (KOER) Self-Test to
verify repair. If repair actions are not
necessary, go to step 3.
• Were any of following heated oxygen
sensor monitor DTCs recorded in step
1: P0156?
Yes
Go to appropriate DTC test.
No
Go to next step.
3 CHECK FOR ECT SENSOR DTCS
Note
• ECT sensor DTCs can indicate that
thermostat is not operating correctly or that
engine coolant level is not filled to
specification. Resulting in above normal
operating temperatures.
• Were any of following ECT sensor DTCs
recorded: P0117, P0118, P0125 and
P1117?
Yes Go to appropriate DTC test.
No Go to next step.
4 CHECK FOR ANY OTHER DTCS
•
Were any other DTCs recorded In step
1?
Yes
Go to appropriate DTC test.
No Go to next step.
5
CHECK DOWNSTREAM HEATED OXYGEN
SENSOR WIRING AND PCM
CONNECTIONS
Note
• If electrical connections of downstream
heated oxygen sensor continuous are
interchanged or crossed, catalyst Efficiency
Monitor Test will fail.
• Inspect wiring of each rear heated oxygen
sensor for proper routing and connection.
• Disconnect PCM, Inspect for damaged or
pushed out pins, corrosion and loose wires.
• Are there any wiring or connection
concerns?
Yes SERVICE any wiring or connection concerns.
For PCM pin concerns, REPLACE PCM.
RECONNECT all components.
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No No PCM root causes related to DTCs or symptoms.
Go to next step.
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