Mazda 6. Manual - part 149
F–118
ON-BOARD DIAGNOSTIC
7
INSPECT MAF PID
• Start engine.
• Access MAF PID using WDS or equivalent.
• Verify that MAF PID changes quickly according
to race engine RPM.
• Is MAF PID response okay?
Yes Go to next step.
No
Replace Mass air flow sensor, then go to Step 18.
8
INSPECT FOR EXCESSIVE AIR SUCTION OF
INTAKE AIR SYSTEM
• Visually inspect for loosen, cracks or damages
hoses on intake air system.
• Is there any malfunction?
Yes Repair or replace source of air suction, then go to Step 18.
No
Go to next step.
9
INSPECT FUEL LINE PRESSURE
• Turn ignition key to OFF.
Note
• If engine won’t start, inspect fuel line
pressure with ignition key ON.
• Inspect fuel line pressure while engine running.
• Is fuel line pressure okay?
Yes Go to step 11.
No
• If fuel line pressure is too high: Replace fuel pump unit,
then go to Step 18.
• If fuel line pressure is too low: Go to next step.
10
INSPECT FUEL LINE FROM FUEL PUMP TO
FUEL DELIVERY PIPE
• Visually inspect fuel line for any leakage.
• Is any fuel leakage found?
Yes Replace suspected fuel line, then go to Step 18.
No
Inspect fuel filters for follows:
• Restriction or clogging at fuel filter (high-pressure side).
• Foreign materials or stain inside fuel filter (low-pressure
side)
Perform following actions as result.
• If restriction or clogging is found at fuel filter (high-
pressure side), replace fuel pump unit.
• If foreign materials or stain is found inside fuel filter
(low-pressure side), clean of fuel tank and filter.
• If all items above are okay, replace fuel pump unit.
Then go to Step 18.
11
CHECK IGNITION COIL OPERATION AND
HIGH-TENSION LEAD WITH TIMING LIGHT
• Verify blinking condition on each cylinders
using timing light at idle.
• Do all cylinders show blinking condition?
Yes Go to Step 15.
No
Go to next step.
12
CHECK HIGH-TENSION LEADS OF NO
BLINKING CYLINDER
• Turn ignition key to OFF.
• Inspect high-tension leads for installation
condition, corrosion on terminal, open lead and
damaged cover.
• Is condition of high-tension lead okay?
Yes Go to next step.
No
Replace faulty high-tension lead, then go to Step 18.
13
INSPECT POWER SUPPLY TERMINAL AT
IGNITION COIL CONNECTOR
• Disconnect ignition coil connector.
• Turn ignition key to ON (Engine OFF).
• Check voltage at ignition coil connector
terminal B (harness-side) and body ground.
• Is voltage B+?
Yes Go to next step.
No
Check for open circuit between ignition coil connector and
ignition switch. Repair or replace wiring harness, then go to
Step 18.
14
INSPECT IGNITION COIL RESISTANCE
• Check ignition coil resistance.
• Is coil resistance okay?
Yes Go to next step.
No
Replace ignition coil, then go to Step 18.
15
INSPECT ENGINE COMPRESSION
• Inspect engine compression.
• Is it okay?
Yes Go to next step.
No
Implement engine overhaul for repairs, then go to Step 18.
STEP
INSPECTION
ACTION