Mazda Mazda6 Workshop Manual Supplement page 365

NO.19 EXCESSIVE BLACK SMOKE
19 EXCESSIVE BLACK SMOKE
• Excessive black smoke is observed in exhaust gas.
DESCRIPTION
• Intake-air system clogging or restriction
• Air leakage from Intake-air system
• Incorrect fuel injection timing
• Erratic signal from CKP sensor
• Fuel pressure sensor or related circuit malfunction
• Boost sensor or related circuit malfunction
• IAT sensor No.2 or related circuit malfunction
• Fuel injector malfunction
• Excessive fuel pressure
• Suction control valve malfunction (built-in supply pump)
• Fuel line clogging or restriction
• Fuel pressure limiter malfunction (built-in common rail)
• Low engine compression
• Improper valve timing
• Base engine malfunction
• EGR system malfunction
• Variable boost control (VBC) system malfunction
POSSIBLE
• Vacuum leakage
CAUSE
• Turbocharger malfunction
• Charge air cooler malfunction
• Intake shutter valve malfunction
• Variable swirl control (VSC) system malfunction
• VSC valve malfunction
• IDM or related circuit malfunction
• Exhaust system and/or catalyst converter restriction or clogging
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.
Diagnostic Procedure
STEP INSPECTION
1 Inspect for following:
• Intake-air system clogging or restriction
• Exhaust system and/or catalyst converter
restriction or clogging
• Charge air cooler condition (restriction or
damaged)
Are all items okay?
2 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?
3 Does any other symptom exist?
4 Inspect for air cleaner element for clogging.
Is air cleaner element okay?
TROUBLESHOOTING
RESULTS
Yes Go to next step.
No Service as necessary.
Repeat Step 1.
Yes DTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
• Open circuit between PCM control relay and PCM
• Open circuit PCM control relay and PCM terminal
• PCM control relay stuck open
• Open or poor GND circuit (PCM terminal 65, 85,
• Poor connection vehicle body GND
No No DTC is displayed:
Go to next step.
Yes Go to appropriate flowchart.
No Go to next step.
Yes Go to next step.
No Repair or replace air cleaner element.
ACTION
terminal 53 or 79
69
103 or 104)
A6E408018881221
F2
F2–213