Mazda 6 Workshop Manual page 239

NO.15 EMISSION COMPLIANCE
15 EMISSION COMPLIANCE
• Fails emissions test.
DESCRIPTION
• Poor fuel quality
• Vacuum leakage
• Air leakage from intake-air system
• Intake-air system restriction or clogging
• Variable swirl control (VSC) system malfunction
• Variable boost control (VBC) system malfunction
• Stuck closed intake shutter valve
• Stuck closed VSC valve
• Turbocharger malfunction
• Guide blade valve malfunction
• Charge air cooler malfunction
• Glow system malfunction
• EGR system malfunction
• EGR valve position sensor malfunction
• EGR water cooler malfunction
• Low coolant temperature
• Engine overheating
• Inadequate fuel pressure
• Fuel pressure limiter malfunction (built-in common rail)
• Suction control valve inspection (built-in supply pump)
• ECT sensor or related circuit malfunction
• MAF/IAT sensor related circuit malfunction
• IAT sensor No.2 or related circuit malfunction
• Fuel pressure sensor or related circuit malfunction
• Incorrect adjustment accelerator position sensor and/or idle switch
• Accelerator position sensor or related circuit malfunction
POSSIBLE
• Idle switch or related circuit malfunction
CAUSE
• Fuel line clogging or restriction
• Supply pump malfunction
• Fuel injector malfunction
• Incorrect fuel injection timing
• Incorrect idle speed
• Erratic signal from CKP sensor
• Erratic signal from CMP sensor
• Boost sensor or related circuit malfunction
• Neutral switch or related circuit malfunction
• VSS or related circuit malfunction
• Low engine compression
• Improper valve timing
• Base engine malfunction
• Exhaust system and/or catalyst converter restriction
• Catalyst converter malfunction
• IDM or related circuit malfunction
Warning
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.
TROUBLESHOOTING
B6E408018881109
F2
F2–227