Mazda MX-6 1998, Workshop Manual

Page: 120 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
I
STEP INSPECTION
ACTION
10
CHECK CONTINUITY OF POWER CIRCUIT
• Key off.
• MAF sensor disconnected.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc. Service as necessary.
• Install breakout box. Leave PCM
disconnected.
• Measure resistance between MAF sensor
connector and Test Pin 71 or 97 at
breakout box.
• Is resistance less than 5.0 ohms?
Yes
Power circuit harness to PCM is okay.
Go to next step.
No Service open in power circuit harness.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
11 CHECK MAF SENSOR CIRCUIT FOR
SHORTS TO GROUND CIRCUIT AND PCM
GROUND CIRCUIT
• Key off.
• MAF sensor disconnected.
• Breakout box installed.
• PCM disconnected.
• Disconnect NGS tester from DLC.
• Measure resistance between Test Pin 88
and Test Pins 36 and 24 or 103 at breakout
box.
• Is each resistance greater than 10,000
ohms?
Yes
MAF sensor signal, PCM ground and ground harness
circuits to PCM are okay.
RECONNECT NGS tester.
Go to next step.
No Service short circuit between MAF sensor signal and
ground or PCM ground.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
12
CHECK PCM GROUND CIRCUIT (BETWEEN
PCM AND MAF SENSOR GROUND) FOR
SHORT TO GROUND CIRCUITS.
• Key off.
• MAF sensor disconnected.
• Breakout box installed. PCM disconnected.
• NGS tester disconnected from DLC.
• Measure resistance between Test Pin 36
and Test Pin 51 or 103 at breakout box.
• Is each resistance greater than 10,000
ohms?
Yes
RECONNECT NGS tester.
Go to next step.
No SERVICE short circuit between PCM ground circuit and
ground circuit.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
w After Repair Procedure
COMPLETE OBD II Drive Mode.
13 CHECK CONTINUITY OF MAF SENSOR
SIGNAL CIRCUIT
• Key off.
• MAF sensor disconnected.
• Breakout box installed. PCM disconnected.
• Measure resistance between MAF circuit at
MAF sensor connector and Test Pin 88 at
breakout box.
• Is resistance less than 5.0 ohms?
Yes
MAF sensor signal harness circuit to PCM is okay.
Go to next step.
No SERVICE open in MAF sensor signal harness circuit.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
14 CHECK GROUND CIRCUIT TO MAF
SENSOR
• Key off.
• MAF sensor disconnected.
• Breakout box installed.
• PCM connected to breakout box.
• Key on, engine off.
• Measure voltage between power circuit
and ground circuit at MAF sensor vehicle
harness connector.
• Is voltage greater than 10.5 volts?
Yes Ground harness circuit from battery negative post to MAF
sensor is okay.
Go to step 4.
No Go to step 3.
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