Mazda MX-6 1998, Workshop Manual

Page: 70 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
STEP INSPECTION
ACTION
33
CHECK RESISTANCE OF FUEL
INJECTOR(S) AND HARNESS
• Key off.
Note
• This erases Continuous Memory DTCs.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion and loose wires.
Service as necessary.
• Install breakout box. Leave PCM
disconnected.
Note
• If misfire DTCs are displayed with fuel
control DTCs, use the misfire DTCs to
determine fuel injector circuits requiring
testing.
• Measure resistance between suspect fuel
injector Test Pin(s) and Test Pin 71/97 at
breakout box using chart below.
Cylinder
Number
Test
pin
Cylinder
Number
Test
pin
1 75 3
74
2
101
4 100
W 6 U 1 0 1 W D 0
• Is resistance between 12.0— 16.0 ohms?
Yes
Fuel injector and harness resistance is okay.
Go to step 36.
No Go to next step.
34 CHECK RESISTANCE OF FUEL INJECTOR
HARNESS
• Key off.
• Breakout box installed. PCM disconnected.
• Disconnect fuel injector harness connector
at suspect fuel injector.
• Measure resistance between Test Pin
71/97 at breakout box and power circuit pin
at suspected fuel injector harness
connector.
• Measure resistance between fuel injector
Test Pin(s) at breakout box and Fuel
Injector Signal Pin at fuel injector
connector. (Refer to step 33 for Injector Pin
location.)
• Is each resistance less than 5.0 ohms?
Yes
Go to next step.
No SERVICE open harness circuit.
REMOVE breakout box.
RECONNECT PCM and all fuel injectors.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
35 CHECK FUEL INJECTOR HARNESS
CIRCUIT FOR SHORT TO POWER OR
GROUND
• Key off.
• Breakout box installed. PCM disconnected.
• Disconnect suspected fuel injector
harness.
• Measure resistance between the fuel
injector Test Pin(s) (refer to step 33) and
Test Pin 71 or 97, 24 and 103 at breakout
box.
• Measure the resistance between the Fuel
injector Test Pin(s) at the breakout box and
chassis ground.
• Is each resistance greater than 10,000
ohms?
Yes Go to next step.
No SERVICE short circuit.
REMOVE breakout box.
RECONNECT PCM and all fuel injectors.
RESET PCM to completely clear DTCs.
xt
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
0 1 -0 1 A -4 2