Mazda 6 2002, Workshop Manual

Page: 335 / 1248

TROUBLESHOOTING
F–205
F
Diagnostic procedure
STEP INSPECTION RESULTS ACTION
1 Verify for following:
•
Vacuum connection
•
Air cleaner element
•
No air leakage from intake-air system
•
No restriction of intake-air system
•
Proper sealing of intake manifold and
components attached to intake manifold:
such as EGR valve, IAC valve
•
Ignition wiring
•
Fuel quality (e.g. proper octane,
contamination, winter/summer blend)
•
Electrical connections
•
Smooth operation of throttle valve
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and
KOER DTCs.
If stall, condition exists retrieve continuous
memory and KOEO DTCs.
Are there any DTCs displayed? Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to next step.
3 Is engine overheating? Yes Go to symptom troubleshooting "No.17 Cooling system
concerns - Overheating".
No Go to next step.
4 Connect WDS or equivalent to DLC-2.
Access RPM, VPWR, MAF, TP and VSS PIDs.
Drive vehicle with monitoring PIDs.
Are PIDs within specifications?
(See
F–45 PCM INSPECTION .)
Yes Go to next step.
No RPM PID:
Inspect CKP sensor and related harness for such as
vibration, intermittent open/short circuit.
VPWR PID:
Inspect for open circuit intermittently.
MAF PID:
Inspect for open circuit of MAF sensor and related wire
harness intermittently.
TP PID:
Inspect if output signal from TP sensor changes
smoothly.
VSS PID:
Inspect for open circuit of VSS and related wire
harness intermittently.
5 Visually inspect CKP sensor and teeth of
crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley
okay? Yes Go to next step.
No Replace malfunctioning parts.
6 Measure gap between CKP sensor and teeth of
crankshaft pulley.
Specification
0.5—1.9 mm {0.020—0.075 in}
Is gap within specification?
Yes Go to next step.
No Adjust CKP sensor.
7 Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white? Yes Spark plug is wet or covered with carbon:
Inspect for fuel leakage from fuel injector.
Spark plug is grayish white:
Inspect for clogged fuel injector.
No Install spark plugs on original cylinders.
Go to next step.
8 Remove and shake PCV valve.
Does PCV valve rattle? Yes Go to next step.
No Replace PCV valve.
9 Verify that throttle lever is resting on throttle
valve stop screw and/or throttle valve orifice
plug.
Is lever in correct position? Yes Go to next step.
No Adjust if necessary.
10 Inspect for restriction in the exhaust system.
Is there any restriction? Yes Inspect exhaust system.
No Go to next step.