Mazda 6 2002 Workshop Manual page 302

Diagnostic procedure
STEP INSPECTION
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?
2 Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and
KOER DTCs.
If stall, condition eists retrieve continuous
memory and KOEO DTCs.
Are there any DTCs displayed?
3 Is engine overheating?
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.)
5 Visually inspect CKP sensor and teeth of
crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley
okay?
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?
7 Inspect spark plug conditions.
Is spark plug wet, covered with carbon or
grayish white?
8 Remove and shake PCV valve.
Does PCV valve rattle?
9 Verify that throttle lever is resting on throttle
valve stop screw and/or throttle valve orifice
plug.
Is lever in correct position?
10 Inspect for restriction in the ehaust system.
Is there any restriction?
TROUBLESHOOTING
RESULTS
Yes Go to net step.
No Service as necessary.
Repeat Step 1.
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to net step.
Yes Go to symptom troubleshooting "No.17 Cooling system
concerns - Overheating".
No Go to net step.
Yes Go to net 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.
Yes Go to net step.
No Replace malfunctioning parts.
Yes Go to net step.
No Adjust CKP sensor.
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 net step.
Yes Go to net step.
No Replace PCV valve.
Yes Go to net step.
No Adjust if necessary.
Yes Inspect ehaust system.
No Go to net step.
ACTION
F–205
F