Mazda RX8 - Fast Idle;Runs on

NO.9 FAST IDLE/RUNS ON
9 FAST IDLE/RUNS ON
DESCRIPTION
• The engine speed continues at fast idle after warm-up.
• The engine runs after the ignition switch is turned off.
POSSIBLE CAUSE
• ECT sensor malfunction
• Air leakage from intake-air system
• Throttle body malfunction (stuck open)
• APP sensor malfunction
• Cruise control system operation improperly
• Improper load signal input
• Improper operation of drive-by-wire control system
Diagnostic procedure
STEP INSPECTION RESULTS ACTION
Yes Go to the next step.
1
Connect the WDS or equivalent to the DLC-2.
Access the ECT PID.
Start and warm up the engine to normal
operating temperature.
Is the ECT PID reading between 82

112°
°°
°C
{180

234°
°°
°F} ?
No
ECT PID is higher than 112°
°°
°C
{234°
°°
°F}:
Go to the symptom troubleshooting
"No.17 Cooling system concerns -
Overheating".
(See NO.17 COOLING SYSTEM
CONCERNS-OVERHEATING .)
ECT PID is less than 82°
°°
°C {180°
°°
°F}:
Go to the symptom troubleshooting
"No.18 Cooling system concerns - Runs
cold".
(See NO.18 COOLING SYSTEM
CONCERNS-RUNS COLD .)
(w) RX8-Engine Troubleshooting
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