Mazda MX-6 1998, Workshop Manual

Page: 262 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP INSPECTION
ACTION
7 CHECK CMP SIGNAL CIRCUIT FOR SHORT
TO GND OR PCM GROUND (BETWEEN
PCM AND CMP SENSOR GROUND
CIRCUIT)
• Key off.
• Breakout box installed, PCM disconnected.
• CMP sensor disconnected.
• Disconnect NGS tester from DLC.
• Measure resistance between Test Pin 85
and Test Pins 51, 103 and 91.
• Is each re sista n ce gre a te r th a n 10,000
ohm s?
Yes Go to next step.
No
SERVICE CMP signal circuit for short to ground or PCM
ground.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
8 CHECK FOR SHORTS IN PCM
• Key off.
• CMP sensor disconnected.
• Breakout box installed.
• Connect PCM to breakout box.
• Measure resistance between Test Pin 85
and Test Pins 5 1 ,1 0 3 ,7 1 , 97, 91, and 23
at breakout box.
• Is each re sista n ce gre a te r than 500
o h m s?
Yes
Go to next step.
No REPLACE PCM.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
9 CHECK CMP SENSOR OUTPUT
• Key off.
• Breakout box installed, PCM connected.
• Reconnect CMP sensor.
• Set voltmeter to AC (to monitor less than
5.0 volts).
• Measure voltage between Test Pin 85 and
Test Pins 51 and 103 at breakout box while
running engine at varying rpm.
• Does AC vo lta g e v a ry g re a te r th a n 0.1
v o lt AC?
Yes REPLACE PCM.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
No REPLACE CMP sensor.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
0 1 -0 1 B -5 6