Mazda MX-6 1998, Workshop Manual

Page: 298 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION
ACTION
11
CHECK B U S (-) CIRCUIT FOR SHORT TO
CHASSIS GROUND
• Key off.
• Breakout box installed. Leave PCM
disconnected.
• Disconnect NGS tester.
• Measure resistance between Test Pin 15 at
breakout box and chassis ground.
• Is re sista n ce gre a te r th a n 10,000 o hm s?
Yes Go to next step.
No
SERVICE short to chassis ground in B U S (-) circuit.
RECONNECT PCM.
REMOVE breakout box.
RERUN OBD Test.
12 CHECK B U S (-) CIRCUIT FOR SHORT TO
POWER
• Key off.
• Breakout box installed. Leave PCM
disconnected.
• Disconnect NGS tester.
• Key on, engine off.
• Measure voltage between Test Pin 15 and
Test Pin 51 or 103 at breakout box.
• Was v o lta g e gre a te r th a n 6.0 v o lts ?
Yes SERVICE Short to power in BUS(-) circuit.
RECONNECT PCM.
REMOVE breakout box.
RERUN OBD Test.
No Go to next step.
13 CHECK DLC BUS(+) CIRCUIT CONTINUITY
• Key off.
• Breakout box installed. Leave PCM
disconnected.
• Measure resistance between Test Pin 16 at
breakout box and BUS(+) circuit at DLC.
• Is re sista n ce less th a n 5.0 o h m s?
Yes Go to next step.
No
SERVICE open in DLC (+) circuit.
RECONNECT PCM.
REMOVE breakout box.
RERUN OBD Test.
14 CHECK BUS(+) CIRCUIT FOR SHORT TO
CHASSIS GROUND
• Key off.
• Disconnect NGS tester.
• Measure resistance between Test Pin 16 at
breakout box and chassis ground.
• Is resistance greater than 10,000 ohms?
Yes There is no short chassis ground in BUS(+) circuit.
Go to next step.
No SERVICE short to power in BUS(+) circuit.
RECONNECT PCM.
REMOVE breakout box.
RERUN OBD Test.
15 CHECK BUS(+) CIRCUIT FOR SHORT TO
POWER
• Key off.
• Breakout box installed. Leave PCM
disconnected.
• Disconnect NGS tester.
• Key on, engine off.
• Measure voltage between Test Pin 16 and
Test Pins 51 or 103 at breakout box.
• Was voltage greater than 1.0 volt?
Yes SERVICE short to power in BUS(+) circuit.
RECONNECT PCM.
REMOVE breakout box.
RERUN OBD Test.
No REPLACE PCM.
01-01B-92