Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

NO.10 LOW IDLE/STALLS DURING DECELERATION DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	Does the engine idle roughly?	Yes	Go to the symptom troubleshooting "No.8 Engine runs rough/rolling idle". (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE .)
1	Does the engine idle roughly?	No	Go to the next step.
2	Turn off the A/C switch and the fan switch. Does the A/C magnetic clutch engage?	Yes	Go to the symptom troubleshooting "No.24 A/C is always on or A/C compressor runs continuously." (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY .)
2		No	Go to the next step.
3	Does the engine knock/ping/detonate?	Yes	Go to the symptom troubleshooting "No. 13 Knocking/pinging/detonation-Acceleration/cruise". (See NO.13 KNOCKING/PINGING/DETONATION-ACCELERATION/CRUISE .)
3	Does the engine knock/ping/detonate?	No	Go to the next step.
4	Verify the following: Proper routing of and no damage to vacuum lines No air leakage from intake-air system Engine mount installation condition (loose) Are all the items normal?	Yes	Go to the next step.
4		No	Service if necessary. Repeat Step 4.
5	Connect the WDS or equivalent to the DLC-2. Turn the ignition switch to the ON position (Engine off). Retrieve any DTCs. Are there any DTCs displayed?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
5		No	Go to the next step.
6	Perform the drive-by-wire control system operation inspection. (See DRIVE-BY-WIRE CONTROL SYSTEM INSPECTION .) Does the drive-by-wire control system work properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the drive-by-wire control system operation inspection results.
7	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold at quick release connector. Plug the opening end of the vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect evaporative emission control system.
7		No	Go to the next step.
8	Connect the WDS or equivalent to the DLC-2. Access APP1, APP2, TP_REL, MAF and VSS PIDs. Monitor each PID while driving vehicle. (See PCM INSPECTION .) Are the PIDs normal?	Yes	Go to the next step.
8		No	If the APP1, APP2 PIDs are not as specified: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION .) If the TP_REL PID is not as specified: Inspect the TP sensor. (See THROTTLE POSITION (TP) SENSOR INSPECTION .) If the MAF PID is not as specified: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION .) If the VSS PID is not as specified: Inspect the ABS or DSC system. (See DTC TABLE .) (See DTC TABLE .)
9	Measure the voltage at the PCM terminal 4P, 2O (MT), 4F (MT) and TCM terminal 2E (AT). (See PCM INSPECTION .) Are the voltages normal?	Yes	Go to the next step.
9		No	If the PCM terminal 4P voltage is not as specified: Inspect the brake switch. (See BRAKE SWITCH INSPECTION .) If the PCM terminal 2O voltage is not as specified (MT): Inspect the neutral switch. (See NEUTRAL SWITCH INSPECTION .) If the PCM terminal 4F voltage is not as specified (MT): Inspect the CPP switch. (See CLUTCH PEDAL POSITION (CPP) SWITCH INSPECTION .) If the TCM terminal 2E voltage is not as specified (AT): Inspect the TR switch. (See TRANSMISSION RANGE (TR) SWITCH INSPECTION .)
10	Turn the ignition switch off. Disconnect the fuel line quick release connector and install the fuel gauge to the fuel line. Inspect the fuel line pressure while the engine running. (See FUEL LINE PRESSURE INSPECTION .) Is the fuel line pressure normal?	Yes	Go to the next step.
10		No	Zero or low: Inspect for clogged fuel line. If normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
11	Perform the fuel injector operation inspection. (See FUEL INJECTOR OPERATION INSPECTION .) Are the fuel injectors operating properly?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning parts, according to the fuel injector operation inspection results.
12	Inspect the fuel injectors for the following: (See FUEL INJECTOR INSPECTION .) Leakage Clogging Injection amount Are the injectors normal?	Yes	Go to the next step.
12		No	Replace the suspected fuel injector.
13	Inspect the engine compression. (See COMPRESSION INSPECTION .) Is it normal?	Yes	Go to step 19.
13		No	Go to the next step.
14	Perform the metering oil pump control inspection. (See METERING OIL PUMP CONTROL INSPECTION .) Does the metering oil pump control operate properly?	Yes	Go to the next step.
14		No	Repair or replace the malfunctioning part according to inspection results. After that overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
15	Check the engine oil condition. Is engine oil low viscosity and/or is there a gasoline odor?	Yes	Replace the engine oil. Inspect the ECT sensor and the related wiring harnesses. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) After that overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
15		No	Go to the next step.
16	Inspect the oil pressure. (See OIL PRESSURE INSPECTION .) Is the oil pressure within the specification?	Yes	Go to the next step.
16		No	Repair or replace the malfunctioning part according to the inspection results. After that overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
17	Turn the ignition switch off. Disconnect the fuel line quick release connector and install the fuel gauge to the fuel line. Start the engine and run it at idle. Measure the fuel line pressure at idle. Is the fuel line pressure correct at idle? (See FUEL LINE PRESSURE INSPECTION .)	Yes	Go to the next step.
17		No	Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .) After that overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
18	Check the oil pipe between the metering oil pump and the metering oil nozzle. Is there air and/or clogging in oil pipe?	Yes	Inspect and repair for leakage and/or clogging in the oil passage at engine. After that overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
18		No	Overhaul or replace the engine. (See ENGINE REMOVAL/INSTALLATION or OVERHAUL - 1.3L (13B-MSB) .)
19	Inspect the torque converter clutch control. (See ROAD TEST .) Does the torque converter clutch control operate properly?	Yes	Inspect for the following: Blockage at intake-air system (between MAF sensor and intake ports) MAF sensor installation
19		No	Repair or replace the malfunctioning parts, according to the torque converter clutch control inspection results.
20	Verify test results. If normal, return to the diagnostic index to service any additional symptoms. If the malfunction remains, inspect the related Service Bulletins and/or the On-line Repair Information and perform the repair or diagnosis.