Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
DTC P0320
Ignition engine speed input circuit malfunction
DESCRIPTION
• Two succesive Profile Ignition Pickup (PIP) pulses occurred resulting in an engine misfire
or stall
[Possible Cause]
• Loose wires/connectors • On-board transmitter (2-way radio)
• Arcing secondary ignition components
STEP
INSPECTION
ACTION
1
CHECK FOLLOWING COMPONENTS
• Loose wires/connectors.
• Arcing secondary ignition components
(coil, wires, plugs, etc.).
• On-board transmitter (2-way radio).
• Are any of the above present? Verify all
2-way radio installation instructions
regarding routing of antenna and power
lead.
Yes SERVICE as necessary.
RERUN OBD Test.
No For No starts:
Go to ENGINE SYMPTOM TROUBLESHOOTING No.5.
For Intermittent faults:
Go to ENGINE SYMPTOM TROUBLESHOOTING No.27.
All others:
Loss of PIP.
REPLACE PCM.
DTC P0325
Knock sensor circuit malfunction
DESCRIPTION
• DTC P0325 indicates misfire of spark knock system failed.
[Possible Cause]
• PCM not receiving signal at high altitude • Damaged knock sensor
• Open or short in harness • Damaged PCM
STEP
INSPECTION ACTION
1 CHECK KNOCK SENSOR VOLTAGE
• Key off.
• Disconnect PCM. Inspect for damage or
pushed out pins, corrosion and loose wires.
Service as necessary.
• Install breakout box.
• Key on, engine running.
• Read DC voltage between terminal 57 and
77 or 103 at the breakout box.
• Is reading between 2.2 and 2.6 volts?
Yes
Go to next step.
No Less than 2.2 volts:
Go to step 4.
Greater than 2.6 volts:
Go to step 6.
2 CHECK FOR INTERMITTENT CIRCUIT
FAULT
• Key on.
• W hile viewing voltmeter, grasp vehicle
harness as close to knock sensor as
possible. Shake and bend small section of
harness from knock sensor to PCM.
• Tap PCM and knock sensor connectors if
possible.
• Is knock sensor reading changing?
Yes ISOLATE fault and service as required.
RECONNECT PCM.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No Go to next step.
3 CHECK FOR VOLTAGE INCREASE
• Key off.
• PCM disconnected.
• Connect NGS tester.
• Start and run engine.
• Monitor voltage on AC setting at idle and at
3,000 rpm between suspect knock sensor
and ground.
• Does AC voltage reading increase?
Yes REPLACE PCM.
RECONNECT all components.
RESET PCM to completely clear DTCs.
rr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No Go to next step.
0 1 -0 1 A -5 0