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Home >> Mazda >> 2006 >> 6 s, 4D Wagon, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Symptom Troubleshooting [Engine Control System L3 With TC)) >> No. 14 Poor Fuel Economy >> Diagnostic procedure

Diagnostic procedure

WARNING: This page is about a different variant/trim than selected.
DIAGNOSTIC PROCEDURE

STEP INSPECTION RESULTS ACTION
1 Inspect for the following:
  • Air cleaner element for contamination
  • Intake-air system restriction
  • Fuel quality (proper octane, contamination, winter/summer blend)
  • Coolant level
  • Brake dragging
  • Clutch slippage
  • Charge air cooler condition (restriction or damaged)
  • Vacuum leakage
  • Fuel leakage
  • MAF sensor contaminated
  • Exhaust system and/or three-way catalytic converter restriction

Are all items normal?
Yes Go to the next step.
No Service if necessary.
Repeat Step 1.
2 Perform the self-test function using the WDS or equivalent.
Turn the ignition switch to the ON position.
Retrieve any DTCs.
Is a DTC displayed?
Yes DTC is displayed:
Go to the appropriate DTC test.
(See DTC TABLE ).
No No DTC is displayed:
Go to the next step.
3 Perform the Cooling Fan Control System Operation Inspection.
(See COOLING FAN CONTROL SYSTEM INSPECTION ).
Does the EGR system operate properly?
Yes Go to the next step.
No Inspect or replace the malfunctioning parts, according to the inspection results.
4 Perform the EGR system operation inspection.
(See EGR CONTROL SYSTEM INSPECTION ).
Does the EGR system operate properly?
Yes Go to the next step.
No Inspect or replace the malfunctioning parts, according to the inspection results.
5 Perform the Variable Swirl Control System Operation Inspection.
(See VARIABLE SWIRL SYSTEM OPERATION INSPECTION ).
Does the variable swirl system work properly?
Yes Go to the next step.
No Inspect or replace the malfunctioning parts, according to the inspection results.
6 Perform the Wastegate Control System Operation Inspection.
(See WASTEGATE CONTROL SYSTEM OPERATION INSPECTION ).
Does the variable swirl system work properly?
Yes Go to the next step.
No Inspect or replace the malfunctioning parts, according to the inspection results.
7 Perform the A/C Cut-off Operation Inspection.
(See A/C CUT-OFF CONTROL SYSTEM INSPECTION ).
Does the A/C Cut-off Operation work properly?
Yes Go to the next step.
No Repair or replace malfunctioning parts, according to the inspection results.
8 Remove and shake the PCV valve.
Does the PCV valve rattle?
Yes Go to the next step.
No Replace the PCV valve.
9 Perform the spark test.
(See SPARK TEST ).
Is the strong blue spark visible at each cylinder?
Yes Go to the next step.
No Inspect or replace the malfunctioning parts, according to the inspection results.
10 Inspect CMP and CKP sensor for the following;
Yes Repair or replace the malfunctioning part according to the inspection results.
No Go to the next step.
11 Connect the WDS or equivalent to the DLC-2.
Access and monitor following PIDs using the data monitor function.
  • ECT
  • MAF
  • IAT
  • IAT2
  • APP
  • TP
  • CPP (PCM terminal 1H)
  • PNP (PCM terminal 1W)
  • MAP
  • VSS

Do the PIDs indicate the correct values according to the engine operating condition?
(See USING THE WDS OR EQUIVALENT ).
Yes Go to the next step.
No Inspect and repair or replace suspected parts and the related harnesses.
If the malfunction remains, perform the intermittent concern troubleshooting procedure.
(See INTERMITTENT CONCERN TROUBLESHOOTING ).
12 Access and monitor the FUEL_PRES PID.
Is the FUEL_PRES PID value within the specification? (See USING THE WDS OR EQUIVALENT ).
Yes Go to Step 16.
No Go to the next step.
13 Is the vehicle accelerate performance normally? Yes Go to the next step.
No Go to Step 15.
14 Inspect the fuel pressure sensor.
(See FUEL PRESSURE SENSOR INSPECTION ).
Is the fuel pressure sensor normal?
Yes Go to Step 16.
No Replace the delivery pipe.
15 Replace the high pressure fuel pump.
Monitor FUEL_PRES PID.
Is the FUEL_PRES PID value within the specified?
(See USING THE WDS OR EQUIVALENT ).
Yes Troubleshooting is completed.
Go to Step 19.
No Go to the next step.
16 Inspect the turbocharger.
(See TURBOCHARGER INSPECTION ).
Is there any problem in turbocharger?
Yes Replace the turbocharger.
No Go to the next step.
17 Inspect the fuel injector for each cylinder.
(See FUEL INJECTOR INSPECTION ).
Are fuel injectors normal?
Yes Go to the next step.
No Replace the suspected fuel injector.
(See FUEL INJECTOR REMOVAL/INSTALLATION ).
18 Measure the compression pressure for each cylinder.
(See COMPRESSION INSPECTION ).
Are compression pressures within the specification?
Yes Replace the injector driver module.
If the problem remains, overhaul the engine.
No Inspect for the following:
  • Damaged valve seat
  • Worn valve stem and valve guide
  • Worn or stuck piston ring
  • Worn piston, piston ring or cylinder
  • Improper valve timing

Service if necessary.
19 Verify test results.
  • If normal, return to the diagnostic index to service any additional symptoms.
  • If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the repair or diagnosis.
    • If the vehicle is repaired, troubleshooting is completed.
    • If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.