Mazda Mazda6 Workshop Manual Supplement page 341

NO.9 FAST IDLE/RUNS ON
9 RUNS IDLE/RUNS ON
• Engine speed continues at fast idle after warm-up.
DESCRIPTION
• Engine runs after engine key turned off.
• ECT sensor or related circuit malfunction
• Incorrect adjustment accelerator position sensor and/or idle switch
• Suction control valve (built-in supply pump)
• Fuel injector malfunction
• IDM or related circuit malfunction
• Vacuum leakage
POSSIBLE
Warning
CAUSE
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep
sparks and flames away from fuel.
• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death
and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE
REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual.
Diagnostic Procedure
STEP INSPECTION
1 Connect WDS or equivalent to DLC-2.
Access ECT PID.
Start and warm-up engine to normal operating
temperature.
Is ECT PID reading between 82—112 °C {180—
233 °F}?
2 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?
3 Inspect suction control valve.
(See F2–54 SUCTION CONTROL VALVE
INSPECTION)
Is suction control valve okay?
4 Inspect fuel injector.
(See F2–56 FUEL INJECTOR
Is fuel injector okay?
5 Inspect adjustment of accelerator position
sensor and idle switch.
(See F2–72 ACCELERATOR POSITION
SENSOR INSPECTION)
(See F2–70 IDLE SWITCH
Are accelerator position sensor and idle switch
adjusted correctly?
6 Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM. (See
End Of Sie
TROUBLESHOOTING
RESULTS
Yes
No
Yes
No
Yes
No
Yes
INSPECTION)
No
Yes
No
INSPECTION)
F2–64 PCM
ACTION
Go to next step.
ECT PID is higher than 112 °C{233 °F}:
Go to symptom troubleshooting "NO.17 COOLING
SYSTEM CONCERNS—OVERHEATING".
ECT PID is less than 82 °C{180 °F}:
Go to symptom troubleshooting "NO.18 COOLING
SYSTEM CONCERNS—RUNS COLD".
DTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
• Open circuit between PCM control relay and PCM
terminal 53 or 79
• Open circuit PCM control relay and PCM terminal
69
• PCM control relay stuck open
• Open or poor GND circuit (PCM terminal 65, 85,
103 or 104)
• Poor connection vehicle body GND
No DTC is displayed:
Go to next step.
Go to next step.
Repair supply pump.
(See F2–54 SUPPLY PUMP
Go to next step.
Replace fuel injector.
(See F2–55 FUEL INJECTOR REMOVAL/
INSTALLATION)
Inspect vacuum leakage.
Adjust accelerator position sensor and idle switch
correctly.
(See F2–73 ACCELERATOR POSITION SENSOR
ADJUSTMENT)
(See F2–71 IDLE SWITCH
REMOVAL/INSTALLATION)
A6E408018881211
INSPECTION)
ADJUSTMENT)
F2–189
F2