Mazda MX-6 1998, Workshop Manual

Page: 79 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
STEP INSPECTION
ACTION
4 CHECK RESISTANCE OF KNOCK SENSOR
CIRCUIT
•
Key off.
• Breakout box installed. PCM disconnected.
• Disconnect knock sensor.
• Measure resistance of knock sensor signal
circuit between Test Pin 57 at breakout box
and same signal pin at vehicle harness
connector.
• Where applicable, measure resistance
between Test Pin 24 at breakout box and
shield pin at vehicle harness connector.
•
Is resistance less than 5.0 ohms?
Yes Go to next step.
No SERVICE open circuit.
RECONNECT all components.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
5
CHECK KNOCK SENSOR CIRCUIT SHORT
TO GROUND
•
Key off.
•
Breakout box installed. PCM disconnected.
•
Knock sensor disconnected.
•
Measure resistance between Test Pin 57
and Test Pins 77 or 103 at breakout box
and chassis ground.
•
Is resistance greater than 10,000 ohms?
Yes
REPLACE knock sensor.
RECONNECT all components.
RESET PCM to completely clear DTCs.
t r
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No SERVICE short circuit.
RECONNECT all components.
RESET PCM to completely clear DTCs.
i t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
6
CHECK KNOCK SENSOR CIRCUIT SHORT
TO POWER
•
Key off.
•
Breakout box installed.
•
Knock sensor disconnected.
•
Key on, engine off.
•
Measure voltage between Test Pin 57 and
Test Pins 77 or 103 at the breakout box.
•
Is voltage less than 0.5 volts?
Yes REPLACE PCM.
RECONNECT all components.
RESET PCM to completely clear DTCs.
e t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No SERVICE short to ground.
RECONNECT all components.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
7
CHECK RESISTANCE OF KNOCK SENSOR
•
Key off.
•
Disconnect PCM from breakout box.
•
Knock sensor connected.
•
Measure resistance between Test Pin 57
and ground at breakout box.
•
Is resistance greater than 5.11
megaohm?
Yes
REPLACE knock sensor.
RECONNECT all components.
RESET PCM to completely clear DTCs.
i t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No REPLACE PCM.
RECONNECT all components.
RESET PCM to completely clear DTCs.
sr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
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