Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

NO.6 CRANKS NORMALLY BUT WILL NOT START [BP, BP WITH TC] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	NOTE: The following test should be performed on vehicles with immobilizer system. Go to Step 12 for vehicles without immobilizer system. Connect WDS or equivalent to DLC-2. Do following condition appear? Engine is not completely started. DTC P1624 is displayed.	Yes	Both conditions appear: Go to Step 4.
1		No	Either or other condition appears: Go to the next step.
2	Does engine stall after approx.2 s since engine is started?	Yes	Go to the next step.
2	Does engine stall after approx.2 s since engine is started?	No	Immobilizer system is okay. Go to Step 12.
3	Is immobilizer control module connector securely connected to immobilizer control module?	Yes	Go to the next step.
3		No	Connect immobilizer control module connector securely. Return to Step 2.
4	Does immobilizer indicator light flash and indicate any of following immobilizer system DTCs? DTC: 01, 02, 03, 11, 21	Yes	Go to "ON-BOARD DIAGNOSTIC FUNCTION " of immobilizer system
4		No	Go to the next step.
5	Does immobilizer indicator light illuminate?	Yes	Go to step 8.
5	Does immobilizer indicator light illuminate?	No	Go to the next step.
6	Does immobilizer indicator light flash and indicate any of following immobilizer system DTCs more than 135 s after ignition switch is turned to ON? DTC: 24, 30	Yes	Go to "ON-BOARD DIAGNOSTIC FUNCTION " of immobilizer system
6		No	Install spark plugs on original cylinders. Go to the next step.
7	Turn ignition switch to OFF. Disconnect immobilizer control module, connector. Connect jumper wire between immobilizer control module connector terminal M and GND. Turn ignition switch to ON. Does immobilizer indicator light illuminate?	Yes	Reconnect immobilizer control module connector. Go to the next step.
7		No	Inspect open circuit between immobilizer control module connector terminal M and instrument cluster. If okay, inspect immobilizer indicator light bulb. Repair or replace if necessary. Reconnect immobilizer control module connector, then return to Step 4.
8	Connect WDS or equivalent to DLC-2 and retrieve DTC. Is any of following DTCs displayed? DTC: P1602, P1603, P1604, P1621, P1622, P1624	Yes	Go to appropriate DTC test.
8		No	Go to the next step.
9	Is there continuity between PCM GND terminals 3A / 3B and GND?	Yes	Go to the next step.
9		No	Repair or replace wiring harness.
10	Turn ignition switch to ON. Measure PCM terminal 4AF voltage. Is PCM terminal 4AF voltage okay? PCM terminal 4AF voltage: Battery voltage	Yes	Go to the next step.
10		No	Repair or replace wiring harness.
11	Disconnect immobilizer control module connector. Turn ignition switch on. Is there battery voltage at immobilizer control module connector terminal J?	Yes	Inspect for open circuit between PCM connector terminal 3S and immobilizer control module connector terminal A.
11		No	Repair or replace wiring harness between immobilizer control module connector terminal J and fuse panel.
12	Verify following: Vacuum connection External fuel shut off or accessory (kill switch, alarm, etc.) Fuel quality; such as proper octane, contamination, winter/summer blend No air leakage from intake-air system Proper sealing of intake manifold and components attached to intake manifold: (EGR valve, IAC valve) Ignition wiring Electrical connections Fuses Smooth operation of throttle valve. Are all items okay?	Yes	Go to the next step.
12		No	Service if necessary and repeat Step 12.
13	Connect WDS or equivalent to DLC-2. Turn ignition switch to ON. Retrieve any DTC. Is "PASSED" displayed?	Yes	No DTC displayed: Go to the next step.
13		No	DTC displayed: Go to appropriate DTC test. Communication error message displayed: Inspect for following: Open circuit between main relay and PCM terminal 4AF Open main relay GND circuit Main relay is stuck open. Open PCM GND circuit (terminal 3A or 3B) Poor connection of vehicle body GND
14	Turn ignition switch to ON. Disconnect TP sensor connector. Measure voltage at TP sensor connector A terminal with ignition switch ON. Voltage 4.5-5.5 V Is voltage okay?	Yes	Go to the next step.
14		No	Go to troubleshooting No.30 "NO.30 REFERENCE VOLTAGE ".
15	Does engine start with TP closed?	Yes	Go to Step 31.
15	Does engine start with TP closed?	No	Go to the next step.
16	Will engine start and run smoothly at part throttle?	Yes	Inspect IAC valve and wiring harness.
16	Will engine start and run smoothly at part throttle?	No	Go to the next step.
17	Connect WDS or equivalent to DLC-2. Access RPM PID. Does RPM PID indicate engine speed while cranking engine?	Yes	Go to the next step.
17		No	Inspect for following: Open or short circuit in CKP sensor Open or short circuit between CKP sensor and PCM terminal 3Y Open or short circuit in CKP sensor harnesses If CKP sensor and harness are okay, go to the next step.
18	Visually inspect CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley okay?	Yes	Go to the next step.
18		No	Replace malfunctioning parts.
19	Measure gap between CKP sensor and teeth of crankshaft pulley. Specification 0.5-1.5 mm {0.020-0.059 in} Is gap within specification?	Yes	Go to the next step.
19		No	Adjust CKP sensor.
20	Inspect for cracks on high-tension leads. Is there any crack on high-tension leads?	Yes	Repair suspected high-tension lead.
20		No	Go to the next step.
21	Is strong blue spark visible at each disconnected high-tension lead during engine cranking?	Yes	Go to the next step.
21		No	Inspect for following: Open or short circuit in ignition coil Open circuit in high-tension leads Open circuit between ignition coil connector GND terminal and GND Open circuit between ignition switch and ignition coil Open circuit between ignition coil and PCM terminal 3F or 31
22	Inspect spark plug conditions. Is spark plug wet, grayish white, or covered with carbon?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector. Spark plug is grayish white: Inspect for clogged fuel injector.
22		No	Install spark plugs on original cylinders. Go to the next step.
23	Remove and shake PCV valve. Does PCV valve rattle?	Yes	Go to the next step.
23	Remove and shake PCV valve. Does PCV valve rattle?	No	Replace PCV valve.
24	Is there any restriction in exhaust system?	Yes	Inspect exhaust system.
24	Is there any restriction in exhaust system?	No	Go to the next step.
25	Install fuel gauge between fuel filter and fuel distributor. Connect a jumper wire between terminal F/P at DLC in engine compartment and GND. Turn ignition switch to ON. Is fuel line pressure correct when ignition switch is turned ON/OFF 5 times? Fuel line pressure 250 kPa {2.55 kgf/cm2, 36.3 psi}	Yes	Go to the next step.
25		No	Zero or low: : Inspect FP circuit. Inspect for open FP relief valve. Inspect for fuel leakage inside pressure regulator. Inspect for clogged main fuel line. Inspect pulsation damper. High: Inspect pressure regulator for the cause of high pressure. Inspect for clogged fuel return line.
26	Visually inspect for fuel leakage at fuel injector O-ring, pulsation damper, and fuel line. Service if necessary. Is fuel line pressure fluctuating after ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION )	Yes	Go to the next step.
26		No	Inspect pressure regulator diaphragm condition. If condition is okay, inspect fuel injector. If condition is not okay, replace pressure regulator.
27	Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Attempt to start engine. Is starting condition improved?	Yes	Inspect if purge solenoid valve is stuck open mechanically. Inspect EVAP control system.
27		No	Go to the next step.
28	Is air leakage felt or heard at intake-air system components while racing engine to higher speed?	Yes	Repair or replace.
28		No	Go to the next step.
29	Inspect engine condition while tapping EGR valve housing. Does engine condition improve?	Yes	Replace EGR valve.
29		No	Go to the next step.
30	Is engine compression correct?	Yes	Inspect valve timing.
30	Is engine compression correct?	No	Inspect for causes.
31	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, replace PCM.