Mazda CX-9 Grand Touring 2007 Manual page 877

2007 ENGINE PERFORMANCE Symptom Troubleshooting (MZI-3.5) - CX-9
6 Inspect the knock sensor.
Is the knock sensor normal?
7
Verify test results.
If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [MZI-3.5].)
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
NO.14 POOR FUEL ECONOMY [MZI-3.5]
DESCRIPTION AND POSSIBLE CAUSES
14 POOR FUEL ECONOMY
DESCRIPTION Fuel economy is unsatisfactory.
2007 Mazda CX-9 Grand Touring
If vehicle is repaired, troubleshooting completed.
If vehicle is not repaired or additional diagnostic information is not
available, replace the PCM.
(see PCM REMOVAL/INSTALLATION [MZI-3.5] .)
Contaminated air cleaner element
Engine cooling system malfunction
Improper ATF level
Weak spark
Poor fuel quality
Erratic or no signal from CMP sensor
Improper variable valve timing control system operation
Improper coolant level
Inadequate fuel pressure
Spark plug malfunction
PCV valve malfunction
Brake dragging
Improper valve timing due to jumping out of timing chain
Contaminated MAF sensor
3.5] .)
High:
Replace the fuel pump unit.
(see FUEL PUMP UNIT
REMOVAL/INSTALLATION [MZI-
3.5] .)
Yes Inspect ignition timing.
No Replace the knock sensor.