Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

NO. 13 KNOCKING/PINGING - ACCELERATION/CRUISE [AJ] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	Connect WDS or equivalent to DLC-2. Access ECT PID. Verify ECT PID is less than 116 °C {241 °F} during driving. Is ECT PID less than specification?	Yes	Go to the next step.
1		No	Inspect cooling system for cause of overheating.
2	Access IAT, MAF PIDs. Monitor each PID. Are PIDs okay?	Yes	Go to the next step.
2	Access IAT, MAF PIDs. Monitor each PID. Are PIDs okay?	No	IAT PID: Inspect IAT sensor. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION .) MAF PID: Inspect MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION .)
3	Connect WDS or equivalent to DLC-2. Turn ignition switch to ON position (Engine OFF). Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to appropriate DTC test.
3		No	No DTC is displayed: Go to the next step.
4	Is engine compression correct? (See COMPRESSION INSPECTION .)	Yes	Go to the next step.
4		No	Inspect for cause.
5	Install fuel pressure gauge between pulsation damper and fuel distributor. Start engine and run it at idle. Measure fuel line pressure at idle. (See FUEL LINE PRESSURE INSPECTION .) Is fuel line pressure correct at idle?	Yes	Go to the next step.
5		No	Zero or low: Inspect fuel pump relay fuel pump circuit. Inspect for clogged fuel line. If okay, replace fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .) High: Replace fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
6	Inspect KS. (See KNOCK SENSOR (KS) INSPECTION .) Is KS okay?	Yes	Inspect ignition timing. (See ENGINE TUNE-UP .)
6		No	Replace KS. (See KNOCK SENSOR (KS) REMOVAL/INSTALLATION .)
7	Verify test results. If okay, return to diagnostic index to service any additional symptoms. If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram PCM if later calibration is available. Retest.