No.7 Slow Return To Idle - Mazda 6 2002 Workshop Manual

STEP
26 Is air leakage felt or heard at intake-air system
components while racing engine to higher
speed?
27 Inspect engine condition while tapping EGR
valve housing.
Is engine condition improved?
28 Note
• The following test should be performed for
vehicles with variable valve timing control
system. Go to net step for vehicles
without variable valve timing control
system.
Inspect variable valve timing control system
operation.
(See F–239 Variable Valve Timing Control
System Operation
Does variable valve timing control work
properly?
29 Is engine compression correct?
30 Verify test results.
• If okay, return to diagnostic inde to service any additional symptoms.
• If malfunction remains, replace PCM.
End Of Sie

NO.7 SLOW RETURN TO IDLE

7 SLOW RETURN TO IDLE
DESCRIPTION Engine takes more time than normal to return to idle speed.
• ECT sensor malfunction
• Thermostat is stuck open.
POSSIBLE CAUSE
• Throttle body malfunction
• Air leakage from intake-air system
Diagnostic procedure
STEP
1 Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and
KOER DTCs.
Are there DTCs displayed?
2 Remove thermostat and inspect operation.
(See E–7 THERMOSTAT REMOVAL/
INSTALLATION.)
(See E–8 THERMOSTAT
Is thermostat okay?
3 Is throttle body free of contaminations?
4 Verify test results.
• If okay, return to diagnostic inde to service any additional symptoms.
• If malfunction remains, replace PCM.
End Of Sie
F–198
TROUBLESHOOTING
INSPECTION
Inspection.)
INSPECTION
INSPECTION.)
RESULTS
Yes Repair or replace.
No Go to net step.
Yes Replace EGR valve.
No Go to net step.
Yes Go to net step.
No Repair or replace malfunctioning parts.
Yes Inspect valve timing.
No Inspect for causes.
RESULTS
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to net step.
Yes ECT and thermostat are okay.
Go to net step.
No Access ECT PID on WDS or equivalent.
Inspect for both ECT PID and temperature gauge on
instrument cluster readings.
If temperature gauge on instrument cluster indicates
normal range but ECT PID is not same as temperature
gauge reading, inspect ECT sensor.
If temperature gauge on instrument cluster indicates
cold range but ECT PID is normal, inspect temperature
gauge and heat gauge unit.
Yes Inspect for air leakage from intake-air system
components while racing engine to higher speed.
No Clean or replace throttle body.
ACTION
A6E398018881W09
ACTION