Mazda 3 Workshop Manual page 400

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
VERIFY CURRENT INPUT SIGNAL
STATUS OF MAF SENSOR
• Connect the WDS or equivalent to the DLC-
2.
• Start the engine.
• Access the MAF PID.
• Verify that the MAF PID changes quickly
according to engine speed.
• Is the PID normal?
INSPECT INTAKE-AIR SYSTEM FOR
EXCESSIVE AIR SUCTION
• Visually inspect the hose in intake-air
10
system for looseness, cracks or damages.
• Is there any malfunction?
INSPECT FUEL LINE PRESSURE
• Perform the "FUEL LINE PRESSURE
INSPECTION".
11
(See FUEL LINE PRESSURE
INSPECTION.)
• Is there any malfunction?
INSPECT FUEL SYSTEM FOR FUEL
LEAKAGE
• Visually inspect fuel leakage in the fuel
12
system.
• Is there fuel leakage?
INSPECT IGNITION COIL WIRING
HARNESSES
• Inspect the ignition coil related wiring
13
harness condition (intermittent open or short
circuit) for all cylinders.
• Are wiring harness conditions normal?
INSPECT IGNITION SYSTEM OPERATION
• Perform spark test.
14
(See Spark Test.)
• Is strong blue spark visible at each
cylinder?
INSPECT ENGINE COMPRESSION
15
• Inspect the engine compression.
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Replace the MAF/IAT sensor, then go to Step
No
17.
Repair or replace the malfunctioning part,
Yes
then go to Step 17.
No Go to the next step.
Yes Go to the next step.
No Go to Step 13.
Repair or replace the malfunctioning part,
Yes
then go to Step 17.
Replace the fuel pump unit, then go to Step
17.
No
(See FUEL PUMP UNIT
REMOVAL/INSTALLATION.)
Yes Go to the next step.
Repair the wiring harnesses, then go to Step
No
17.
Yes Go to the next step.
Repair or replace malfunctioning part
according to spark test result.
No
Then go to Step 17.
Yes Go to the next step.
No Overhaul engine, then go to Step 17.
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