Symptom Troubleshooting - Engine: Diagnosis

Inspection Method for Sensors

Connect the WDS or equivalent to the DLC-2.
Turn the ignition switch to the ON position (Engine off). NOTE: If the engine starts and runs, perform the following steps during idle.
Access PIDs for the switch you are inspecting.
Vibrate the sensor slightly with your finger. If PID value is unstable or malfunction occurs, check for poor connection or poorly mounted sensor or both

Scheme 5

Scheme 5: Inspection Method for Actuators or Relays

Connect the WDS or equivalent to the DLC-2.
Turn the ignition switch to the ON position (Engine off). NOTE: If the engine starts and runs, perform the following steps during idle.
Prepare the output state control function for actuators or relays that you are inspecting.
Vibrate the actuator or relay with your finger for 3 s after output state control function is activated. If variable click sound is heard, check for poor connection or poorly mounted actuator or both, or the relay. NOTE: Vibrating relays too strongly may result in open relays.

ENGINE SYMPTOM TROUBLESHOOTING [LF]

Confirm trouble symptom using the following diagnostic index, then go to appropriate troubleshooting table.

Diagnostic Index

No.	TROUBLESHOOTING ITEM		DESCRIPTION	REFERENCE
1	Melting of main or other fuses			(See NO.1 MELTING OF MAIN OR OTHER FUSES [LF] .)
2	MIL illuminates		The MIL is illuminated incorrectly.	(See NO.2 MIL ILLUMINATES [LF] .)
3	Will not crank		The starter does not work.	(See NO.3 WILL NOT CRANK [LF] .)
4	Hard to start/long crank/erratic start/erratic crank		The starter cranks the engine at normal speed but the engine requires excessive cranking time before starting.	(See NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [LF] .)
5	Engine stalls.	After start/at idle	The engine stops unexpectedly at idle and/or after start or both.	(See NO.5 ENGINE STALLS-AFTER START/AT IDLE [LF] .)
6	Cranks normally but will not start		The starter cranks engine at normal speed but the engine will not run.	(See NO.6 CRANKS NORMALLY BUT WILL NOT START [LF] .)
7	Slow return to idle		The engine takes more time than normal to return to idle speed.	(See NO.7 SLOW RETURN TO IDLE [LF] .)
8	Engine runs rough/rolling idle		The engine speed fluctuates between the specified idle speed and lower speed and the engine shakes excessively.	(See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [LF] .)
9	Fast idle/runs on		The engine speed continues at fast idle after warm-up. The engine runs after the ignition switch is turned off.	(See NO.9 FAST IDLE/RUNS ON [LF] .)
10	Low idle/stalls during deceleration		The engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.	(See NO.10 LOW IDLE/STALLS DURING DECELERATION [LF] .)
11	Engine stalls/quits.	Acceleration/cruise	The engine stops unexpectedly at the beginning of acceleration or during acceleration. The engine stops unexpectedly while cruising.	(See NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [LF] .)
	Engine runs rough.	Acceleration/cruise	The engine speed fluctuates during acceleration or cruising.
	Misses	Acceleration/cruise	The engine misses during acceleration or cruising.
	Buck/jerk	Acceleration/cruise/deceleration	The vehicle bucks/jerks during acceleration, cruising, or deceleration.
	Hesitation/stumble	Acceleration	A momentary pause at the beginning of acceleration or during acceleration.
	Surges	Acceleration/cruise	A momentary minor irregularity in engine output.
12	Lack/loss of power	Acceleration/cruise	The performance is poor under load (such as power down when climbing hills).	(See NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [LF] .)
13	Knocking/pinging/detonation	Acceleration/cruise	Sound is produced when the air/fuel mixture is ignited by something other than the spark plug (such as hot spot in combustion chamber).	(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [LF] .)
14	Poor fuel economy		The fuel economy is unsatisfactory.	(See NO.14 POOR FUEL ECONOMY [LF] .)
15	Emission compliance		Fails emissions test.	(See NO.15 EMISSION COMPLIANCE [LF] .)
16	High oil consumption/leakage		The oil consumption is excessive.	(See NO.16 HIGH OIL CONSUMPTION/LEAKAGE [LF] .)
17	Cooling system concerns	Overheating	The engine runs at higher than normal temperature/overheats.	(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] .)
18	Cooling system concerns	Runs cold	The engine does not reach normal operating temperature.	(See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF] -)
19	Exhaust smoke		Blue, black, or white smoke from exhaust system	(See NO.19 EXHAUST SMOKE [LF] .)
20	Fuel odor (in engine compartment)		Gasoline fuel smell or visible leakage	(See NO.20 FUEL ODOR (IN ENGINE COMPARTMENT) [LF] .)
21	Engine noise		Engine noise from under hood	(See NO.21 ENGINE NOISE [LF] .)
22	Vibration concerns (engine)		Vibration from under hood or driveline	(See NO.22 VIBRATION CONCERNS (ENGINE) [LF] .)
23	A/C does not work sufficiently.		The A/C compressor magnetic clutch does not engage when A/C is turned on.	(See NO.23 A/C DOES NOT WORK SUFFICIENTLY [LF] .)
24	A/C is always on or A/C compressor runs continuously.		The A/C compressor magnetic clutch does not disengage.	(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [LF] .)
25	A/C does not cut off under wide open throttle conditions.		The A/C compressor magnetic clutch does not disengage under wide open throttle.	(See NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS [LF] .)
26	Exhaust sulphur smell		Rotten egg smell (sulphur) from exhaust	(See NO.26 EXHAUST SULPHUR SMELL [LF] .)
27	Fuel refill concerns		The fuel tank does not fill smoothly.	(See NO.27 FUEL REFILL CONCERNS [LF] .)
28	Fuel filling shut off issues		The fuel does not shut off properly.	(See NO.28 FUEL FILLING SHUT OFF CONCERNS [LF] .)
29	Spark plug condition		An incorrect spark plug condition.	(See NO.29 SPARK PLUG CONDITION [LF] .)
30	AT concerns	Upshift/downshift engagement	AT concerns not related to engine performance.	(See SYMPTOM TROUBLESHOOTING ITEM TABLE [SJ6A-EL] .)

DIAGNOSTIC INDEX

Scheme 6

Scheme 6: QUICK DIAGNOSTIC TABLE [LF]

Scheme 7

Scheme 8

Scheme 9

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	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	DTC is displayed: Go to appropriate the DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Inspect instrument cluster operation. (See INSTRUMENT CLUSTER INSPECTION .)
2	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

MIL ILLUMINATES DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	NOTE: The following test should be performed on the advanced keyless entry system. If not equipped, go to the next step. Start the engine using the mechanical ignition key.Does the engine start?	Yes	Inspect advanced keyless entry system and repair or replace according to inspection result. (See SYMPTOM TROUBLESHOOTING TABLE [KEYLESS ENTRY SYSTEM] .)
1		No	Go to the next step.
2	Connect the WDS or equivalent to the DLC-2. Do the following conditions appear? The engine is not completely started. DTC P1260 is displayed.	Yes	Both conditions appear: Go to Step 4.
2		No	Either or other condition appears: Go to the next step.
3	Turn the ignition switch to the ON position. Is the coil connector securely connected to the coil?	Yes	Go to the next step.
3		No	Connect the coil connector securely. Return to Step 1.
4	Does the security light flush?	Yes	Go to the next step.
4	Does the security light flush?	No	Inspect and repair or replace the following: Wiring harnesses and connectors from keyless control module terminal 3F and instrument cluster terminal 2F Instrument cluster (See INSTRUMENT CLUSTER INSPECTION .)
5	Connect the WDS or equivalent to the DLC-2 and retrieve DTC for PCM, instrument cluster and keyless control module. DTC PCM: B1342, U0073, U0155 Instrument cluster: B1213, B1600, B1601, B1602, B1681, B2103, B2139, B2431, U0100, U0214 Keyless control module (with advanced keyless entry system): B1681, B2103, B1213	Yes	Go to appropriate DTC inspection. (See DTC TABLE [LF] .)
5		No	Go to the next step.
6	Inspect for the following wiring harnesses and connectors: With advanced keyless entry system Between coil terminal A and keyless control module terminal 2S Between coil terminal B and keyless control module terminal 2Q Without advanced keyless entry system Between coil terminal A and instrument cluster terminal 3AA Between coil terminal B and instrument cluster terminal 3Y Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
6		No	Go to the next step, (with advanced keyless entry system) Go to the Step 8. (without advanced keyless entry system)
7	Inspect the following wiring harnesses and connectors for an open or short circuit: Between keyless control module terminal 4A and instrument cluster terminal 2Q Between keyless control module terminal 4C and instrument cluster terminal 2S Is there any malfunction?	Yes	Repair or replace wiring harness and connectors.
7		No	Go to the next step.
8	Inspect for the following wiring harnesses and connectors: Between PCM terminal 1AM and instrument cluster terminal 1J Between PCM terminal 1AI and instrument cluster terminal 1L Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
8		No	Go to the next step.
9	Is there continuity between PCM terminal 1B and starter relay with clutch pedal depressed (MT with starter interlock system), P or N position (AT)?	Yes	Go to the next step.
9		No	Repair or replace wiring harness.
10	Inspect the following: Battery connection Battery condition Transaxle is in Park or Neutral. (AT) Clutch is fully depressed. (MT) Fuses Are all items normal?	Yes	Go to the next step.
10		No	Service if necessary. Repeat Step 9.
11	Is clicking sound heard from starter when the ignition switch is turned to START?	Yes	Go to the next step.
11		No	Go to Step 13.
12	Inspect the starting system. (See STARTER INSPECTION [LF] .) Is starting system normal?	Yes	Inspect for seized/hydrolocked engine, flywheel or drive plate. (See FLYWHEEL INSPECTION .)
12		No	Repair or replace components if required.
13	Do any other electrical accessories function?	Yes	Go to the next step.
13	Do any other electrical accessories function?	No	Inspect the charging system. (See BATTERY INSPECTION [LF] .) (See GENERATOR INSPECTION [LF] .)
14	NOTE: The following test should be performed on AT only. For MT, go to the next step. Connect the WDS or equivalent to the DLC-2. Access TR PID.Turn the ignition switch to the ON position.Is TR PID indicated P/N when selecting P or N position?	Yes	Go to the next step.
14		No	Inspect adjustment of TR switch. If TR switch is adjusted properly, inspect for open circuit between TR switch and PCM terminal 1B or starter.
15	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	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [LF] .) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay and PCM terminal 1AW or 1BE Open circuit in wiring harness between main relay terminal E and PCM terminal 1Q Main relay is stuck open. Open or short circuit in wiring harness between DLC and PCM terminals 1AM or 1AI Open or poor GND circuit (PCM terminal 1AZ, 1BH, 1BD, 1BB) Poor connection of vehicle body GND
15		No	No DTC is displayed: Inspect the following: START circuit in ignition switch Open circuit in wiring harness between ignition switch and starter Starter interlock switch (MT)
16	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
The following test should be performed on the advanced keyless entry system. If not equipped, go to the next step.

NOTE
The following test should be performed on AT only. For MT, go to the next step.

WILL NOT CRANK DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Vacuum leakage Proper fuel quality (such as proper octane, contamination, winter/summer blend) Loose bands on intake-air system Cracks on intake-air system parts Intake-air system restriction (such as air cleaner element, fresh air duct.) Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Is engine overheating?	Yes	Go to symptom troubleshooting "No.17 Cooling system concerns-Overheating". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] .)
3	Is engine overheating?	No	Go to the next step.
4	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
4		No	Repair the wiring harnesses.
5	Inspect the spark plug conditions. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector. Spark plug is grayish white: Inspect the fuel injector for clogging.
5		No	Install the spark plugs on original cylinders. Go to the next step.
6	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are the CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
6		No	Replace the malfunctioning part.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
8	Attempt to start engine at part throttle. Does engine run smoothly at part throttle?	Yes	Inspect the electronic throttle control system operation. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .)
8		No	Go to the next step.
9	Install the fuel pressure gauge between the fuel pipe and fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position. Is fuel line pressure correct with ignition switch ON? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
9		No	Zero or low: Inspect the fuel pump relay and the fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
10	Is the fuel line pressure held after ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
10		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [LF] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
11	Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Start engine. Is starting condition improved?	Yes	Inspect if the purge solenoid valve is stuck open.
11		No	Go to the next step.
12	Inspect the MAF sensor for following: Contamination MAF sensor terminal B voltage (GND circuit) Is there any contamination?	Yes	Repair or replace the malfunctioning part.
12		No	Go to the next step.
13	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
13		No	Go to the next step.
14	Inspect engine condition while tapping EGR valve housing. Does engine condition improve?	Yes	Replace the EGR valve. (See EGR VALVE REMOVAL/INSTALLATION [LF] .)
14		No	Go to the next step.
15	Inspect the starting system. (See STARTER INSPECTION [LF] .) Is starting system normal?	Yes	Inspect for loose connectors or poor terminal contact. If there is no malfunction, remove EGR valve and visually inspect for mechanically stuck EGR valve.
15		No	Repair or replace components as required.
16	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Connect the WDS or equivalent to the DLC-2. Do the following conditions appear? The engine is not completely started. DTC P1260 is displayed.	Yes	Both conditions appear: Go to Step 3.
1		No	Either or other condition appears: Go to the next step.
2	Does the engine stall after approx. 2 s since the engine is started?	Yes	Go to the next step.
2		No	Immobilizer system is normal. Go to Step 8.
3	Is coil connector securely connected to coil?	Yes	Go to the next step.
3	Is coil connector securely connected to coil?	No	Connect the coil connector securely. Return to Step 2.
4	Does the security light flush?	Yes	Go to the next step.
4	Does the security light flush?	No	Inspect and repair or replace the following: Wiring harnesses and connectors from keyless control module terminal 3F and instrument cluster terminal 2F Instrument cluster (See INSTRUMENT CLUSTER INSPECTION .)
5	Connect the WDS or equivalent to the DLC-2 and retrieve DTC for PCM, instrument cluster and keyless control module (with advanced keyless entry system). Are any of the following DTCs displayed? DTC PCM: B1342, U0073, U0155 Instrument cluster: B1213, B1600, B1601, B1602, B1681, B2103, 2139, B2431, U0110, U0214 Keyless control module (with advanced keyless entry system): B1681, B2103, B1213	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
5		No	Go to the next step.
6	Inspect for the following wiring harnesses and connectors: With advanced keyless entry system: Between coil terminal A and keyless control module terminal 2S Between coil terminal B and keyless control module terminal 2Q Without advanced keyless entry system: Between coil terminal A and instrument cluster terminal 3AA Between coil terminal B and instrument cluster terminal 3Y Is there any malfunction?	Yes	Repair or replace the suspected wiring harness and connector.
6		No	Go to the next step, (with advanced keyless entry system.) Go to Step 8. (without advanced keyless entry system.)
7	Inspect the following wiring harnesses and connectors for an open or short circuit: Between keyless control module terminal 4A and instrument cluster terminal 2Q Between keyless control module terminal 4C and instrument cluster terminal 2S Is there any malfunction?	Yes	Repair or replace wiring harness and connectors.
7		No	Go to the next step.
8	Inspect for the following wiring harnesses and connectors: Between PCM terminal 1AM and instrument cluster terminal 1J Between PCM terminal 1AI and instrument cluster terminal 1L Is there any malfunction?	Yes	Repair or replace the suspected wiring harness and connector.
8		No	Go to the next step.
9	Verify the following: Vacuum connection Air cleaner element No air leakage from intake-air system No restriction of intake-air system Proper sealing of intake manifold and components attached to intake manifold: EGR valve Ignition wiring Fuel quality: proper octane, contamination, winter/summer blend Electrical connections Smooth operation of throttle valve Are all items normal?	Yes	Go to the next step.
9		No	Service if necessary. Repeat Step 9.
10	Connect the WDS or equivalent to the DLC-2. Access the APP1 and APP2 PIDs. Crank the engine with accelerator pedal released. Are the APP1 and APP2 PIDs indicating that the accelerator pedal is in the released position?	Yes	Go to the next step.
10		No	Inspect for the following: APP sensor Wiring harnesses and connectors for following: PCM terminal 1AJ-APP sensor terminal A PCM terminal 1AV-APP sensor terminal B PCM terminal 1AP-APP sensor terminal C PCM terminal 1AL-APP sensor terminal D PCM terminal 1AS-APP sensor terminal E PCM terminal 1AO-APP sensor terminal F
11	Connect the WDS or equivalent to the DLC-2. Access the TP PID. Crank the engine with accelerator pedal released. Are the TP PID indicates the closed throttle position?	Yes	Go to the next step.
11		No	Inspect for the following: TP sensor Wiring harnesses and connectors for following: PCM terminal 2AK-TP sensor terminal F PCM terminal 2AO-TP sensor terminal E PCM terminal 2AP-TP sensor terminal C PCM terminal 2AL-TP sensor terminal D
12	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	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [LF] .) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay and PCM terminal 1AW or 1BE Open main relay GND circuit Main relay is stuck open. Open or short circuit in wiring harness between DLC and PCM terminals 1AM or 1AI Open or poor GND circuit (PCM terminal 1AZ, 1BB, 1BD, 1BH) Poor connection of vehicle body GND
12		No	No DTC is displayed: Go to the next step.
13	Attempt to start engine at part throttle. Does engine run smoothly at part throttle?	Yes	Inspect electronic throttle control system operation. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .)
13		No	Go to the next step.
14	Connect the WDS or equivalent to the DLC-2. Access RPM PID. Is RPM PID indicating engine speed during engine cranking?	Yes	Go to the next step.
14		No	Inspect for the following: Open or short circuit in CKP sensor Open or short circuit in wiring harness between CKP sensor terminal A and PCM terminal 2AB Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2W Open or short circuit in wiring harness between CKP sensor terminal C and PCM terminal 2AQ Open or short circuit in CKP sensor wiring harnesses If CKP sensor and wiring harness are normal, go to the next step.
15	Visually inspect CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
15		No	Replace the malfunctioning part.
16	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
16		No	Repair the wiring harnesses.
17	Perform the spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step. If symptoms occurs with the A/C on, go to Step 24.
17		No	Repair or replace the malfunctioning part according to spark test result.
18	Inspect the spark plug condition. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from injector. Spark plug is grayish white: Inspect the fuel injector for clogging.
18		No	Install spark plugs on original cylinders. Go to the next step.
19	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
19	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
20	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
20		No	Go to the next step.
21	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position. Is fuel line pressure correct with ignition switch ON? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
21		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
22	Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is fuel line pressure held after ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
22		No	Inspect the fuel injector. If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
23	NOTE: The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step. Connect pressure gauges to A/C low and high pressure side lines.Turn A/C on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK .)	Yes	Go to the next step.
23		No	If A/C is always on, go to 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 [LF] .) For other symptoms, inspect the following: Refrigerant charging amount Condenser fan operation
24	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated?	Yes	Inspect if purge solenoid valve is stuck open. Inspect evaporative emission control system.
24		No	Go to the next step.
25	Is air leakage felt or heard at intake-air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part.
25		No	Go to the next step.
26	Inspect the engine condition while tapping EGR valve housing. Does the engine condition improve?	Yes	Replace the EGR valve.
26		No	Go to the next step.
27	Inspect variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION .) Does variable valve timing control function properly?	Yes	Go to the next step.
27		No	Repair or replace the malfunctioning parts according to variable valve timing control system operation inspection results.
28	Is the engine compression correct?	Yes	Inspect the valve timing.
28	Is the engine compression correct?	No	Inspect for cause.
29	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step.

ENGINE STALLS-AFTER START/AT IDLE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Connect the WDS or equivalent to the DLC-2. Do any of the following conditions appear? Engine does not completely start. DTC P1260 is displayed.	Yes	Both conditions appear: Go to Step 3.
1		No	Either or other condition appears: Go to the next step.
2	Does engine stall after approx. 2 s from when it is started?	Yes	Go to the next step.
2		No	Immobilizer system is normal. Go to Step 8.
3	Is the coil connector securely connected to the coil?	Yes	Go to the next step.
3	Is the coil connector securely connected to the coil?	No	Connect the coil connector securely. Return to Step 2.
4	Does the security light flush?	Yes	Go to the next step.
4	Does the security light flush?	No	Inspect and repair or replace the following: Wiring harnesses and connectors from keyless control module terminal 3F and instrument cluster terminal 2F Instrument cluster (See INSTRUMENT CLUSTER INSPECTION .)
5	Connect the WDS equivalent to the DLC-2 and retrieve the DTC for PCM, instrument cluster and keyless control module (with advanced keyless entry system). Are any of the following DTCs displayed? DTC PCM: B1342, U0073, U0155 Instrument cluster: B1213, B1600, B1601, B1602, B1681, B2103, B2139, B2431, U0100, U0214 Keyless control module (with advanced keyless entry system): B1681, B2103, B1213	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
5		No	Go to the next step.
6	Inspect the following wiring harnesses and connectors: With advanced keyless entry system: Between coil terminal A and keyless control module terminal 2S Between coil terminal B and keyless control module terminal 2Q Without advanced keyless entry system: Between coil terminal A and instrument cluster terminal 3AA Between coil terminal B and instrument cluster terminal 3Y Is there any malfunction?	Yes	Repair or replace the suspected wiring harness and connector.
6		No	Go to the next step. (with advanced keyless entry system.) Go to Step 8. (without advanced keyless entry system.)
7	Inspect the following wiring harnesses and connectors for an open or short circuit: Between keyless control module terminal 4A and instrument cluster terminal 2Q Between keyless control module terminal 4C and instrument cluster terminal 2S Is there any malfunction?	Yes	Repair or replace wiring harness and connectors.
7		No	Go to the next step.
8	Inspect the following wiring harnesses and connectors: Between PCM terminal 1AM and instrument cluster terminal 1J Between PCM terminal 1AI and instrument cluster terminal 1L Is there any malfunction?	Yes	Repair or replace the suspected wiring harness and connector.
8		No	Go to the next step.
9	Verify the following: Vacuum connection External fuel shut off or accessory (such as kill switch, alarm) Fuel quality: proper octane, contamination, winter/summer blend No air leakage from intake-air system Intake-air system restriction (such as air cleaner element, fresh air duct) Proper sealing of intake manifold and components attached to intake manifold: EGR valve Ignition wiring Electrical connections Fuses Smooth operation of throttle valve Are all items normal?	Yes	Go to the next step.
9		No	Service if necessary. Repeat Step 9.
10	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay and PCM terminal 1AW or 1BE Open main relay GND circuit Open or short circuit in wiring harness between DLC and PCM terminal 1AM or 1AI Main relay is stuck open. Open or poor GND circuit (PCM terminal 1AZ, 1BB, 1BD, 1BH) Poor connection of vehicle body GND
10		No	No DTC is displayed: Go to the next step.
11	Connect the WDS or equivalent to the DLC-2. Access the APP1 and APP2 PIDs. Crank the engine with accelerator pedal released. Are the APP1 and APP2 PIDs indicating that the accelerator pedal is in the released position?	Yes	Go to the next step.
11		No	Inspect for the following: APP sensor Wiring harnesses and connectors for following: PCM terminal 1AJ-APP sensor terminal A PCM terminal 1AV-APP sensor terminal B PCM terminal 1AP-APP sensor terminal C PCM terminal 1AL-APP sensor terminal D PCM terminal 1AS-APP sensor terminal E PCM terminal 1AO-APP sensor terminal F
12	Connect the WDS or equivalent to the DLC-2. Access the TP PID. Crank the engine with accelerator pedal released. Are the TP PID indicates the closed throttle position?	Yes	Go to the next step.
12		No	Inspect for the following: TP sensor Wiring harnesses and connectors for following: PCM terminal 2AK-TP sensor terminal F PCM terminal 2AO-TP sensor terminal E PCM terminal 2AP-TP sensor terminal C PCM terminal 2AL-TP sensor terminal D
13	Does the engine start with the throttle valve closed?	Yes	Go to Step 29.
13	Does the engine start with the throttle valve closed?	No	Go to the next step.
14	Will the engine start and run smoothly at part throttle?	Yes	Inspect the electronic throttle control system operation. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .)
14	Will the engine start and run smoothly at part throttle?	No	Go to the next step.
15	Connect the WDS or equivalent to the DLC-2. Access RPM PID. Is RPM PID indicating the engine speed when cranking the engine?	Yes	Go to the next step.
15		No	Inspect for the following: Open or short circuit in CKP sensor Open or short circuit in wiring harness between CKP sensor terminal A and PCM terminal 2AB Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2W Open or short circuit in wiring harness between CKP sensor terminal C and PCM terminal 2AQ Open or short circuit in CKP sensor wiring harnesses If CKP sensor and wiring harness are normal, go to the next step.
16	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
16		No	Replace the malfunctioning part.
17	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
17		No	Repair the wiring harnesses.
18	Perform the spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning part according to spark test result.
19	Inspect the spark plug conditions. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from injector. Spark plug is grayish white: Inspect the fuel injector for clogging.
19		No	Install the spark plugs on original cylinders. Go to the next step.
20	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
20	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
21	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
21		No	Go to the next step.
22	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position. Is fuel line pressure correct when ignition switch is turned on/off five times? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
22		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
23	Visually inspect the fuel injector O-ring and fuel line for fuel leakage. Service if necessary. Is the fuel line pressure held after the ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
23		No	Inspect the fuel injector. If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
24	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Start the engine. Is starting condition improved?	Yes	Inspect if the purge solenoid valve is stuck open mechanically. Inspect the evaporative emission control system.
24		No	Go to the next step.
25	Is air leakage felt or heard at intake-air system components while racing engine to higher speed?	Yes	Repair or replace the malfunctioning part.
25		No	Go to the next step.
26	Inspect the engine condition while tapping EGR valve housing. Is engine condition improved?	Yes	Replace the EGR valve.
26		No	Go to the next step.
27	Inspect the variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION .) Does variable valve timing control function properly?	Yes	Go to the next step.
27		No	Repair or replace the malfunctioning part.
28	Is the engine compression correct?	Yes	Inspect the valve timing.
28	Is the engine compression correct?	No	Inspect for causes.
29	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

CRANKS NORMALLY BUT WILL NOT START DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Go to the next step.
2	Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [LF] .) (See THERMOSTAT INSPECTION [LF] .) Is thermostat normal?	Yes	ECT and thermostat are normal. Go to the next step.
2		No	Access ECT PID on the WDS or equivalent. Inspect for both ECT PID and temperature gauge on instrument cluster readings. If temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor. If temperature gauge on instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
3	Is throttle body free of contamination?	Yes	Inspect for air leakage from the intake-air system components while racing the engine to higher speed.
3	Is throttle body free of contamination?	No	Clean or replace throttle body.
4	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

SLOW RETURN TO IDLE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Warm up the engine. Idle the engine for 5 min. Is the symptom disappeared?	Yes	Troubleshooting completed. (Cause of this symptom is that the idle learning of electronic throttle control system is not completed.)
1		No	Go to the next step.
2	Verify the following: External fuel shut off or accessory (such as kill switch, alarm) 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 Ignition wiring Electrical connections Fuses Smooth operation of throttle valve PCM GND circuit (1AZ, 1BB, 1BD, 1BH) Are all items normal?	Yes	Go to the next step.
2		No	Service if necessary. Repeat Step 2.
3	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
3		No	No DTC is displayed: Go to the next step.
4	Is the engine overheating?	Yes	Go to symptom troubleshooting NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] .
4	Is the engine overheating?	No	Go to the next step.
5	Connect the WDS or equivalent to the DLC-2. Access MAF PID. Drive vehicle with monitoring PID. Is MAF PID within specification?	Yes	Go to the next step.
5		No	Inspect for open or short circuit of MAF sensor and related wiring harness.
6	NOTE: The following test is for engine running at rough idle with A/C on. If other symptoms exist, go to the next step. Connect pressure gauge to A/C low and high pressure side lines.Start engine and idle it.Turn the A/C switch on.Measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK .)	Yes	Go to the next step.
6		No	If the A/C is always on, go to symptom troubleshooting NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [LF] . For other symptoms, inspect the following: Refrigerant charging amount Condenser fan operation
7	NOTE: The following test is for engine running rough with P/S on. If other symptoms exist, go to the next step. Connect the WDS or equivalent to the DLC-2.Start the engine and idle it.Retrieve any DTCs for EPS.Is there any EPS DTC displayed?	Yes	Go to appropriate the DTC inspection. (See DTC TABLE [LF] .)
7		No	Go to the next step.
8	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are the CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
8		No	Replace the malfunctioning part.
9	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
9		No	Repair the wiring harnesses.
10	Inspect the spark plug condition. Is the spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from injector. Spark plug is grayish white: Inspect the fuel injector for clogging.
10		No	Install the spark plugs on original cylinders. Go to the next step.
11	Perform the electronic throttle control system operation inspection. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .) Does the electronic throttle control system function properly?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning part according to electronic throttle control system operation inspection results.
12	Install fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and run it at idle. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
12		No	Low: Inspect the fuel line for clogging. If there is no malfunction, replace fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
13	Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. Service if necessary. Does fuel line pressure hold after ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
13		No	Inspect fuel injector. If fuel injector is normal, replace fuel pump unit.
14	Connect the WDS or equivalent to the DLC-2. Start the engine and idle it. Access LONG FT1 PID. Measure LONG FT1 PID at idle. Is PID value normal? (See PCM INSPECTION [LF] .)	Yes	Go to the next step.
14		No	LONG FT1 PID is out of specification. Less than specification (too rich): Inspect EVAP control system. If system is normal, go to Step 14. Greater than specification (too lean): Inspect for air leakage at intake-air system components. If system is normal, go to the next step.
15	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Start the engine. Does the engine condition improve?	Yes	Check if purge solenoid valve is stuck open mechanically. Inspect EVAP control system.
15		No	Go to the next step.
16	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
16	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
17	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
17		No	Go to the next step.
18	Visually inspect the CMP sensor and teeth of camshaft. Are the CMP sensor and teeth of camshaft normal?	Yes	Go to the next step.
18		No	Replace the malfunctioning part.
19	Inspect the engine condition while tapping EGR valve housing. Does the engine condition improve?	Yes	Replace the EGR valve.
19		No	Go to the next step.
20	Inspect variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION .) Does variable valve timing control system function properly?	Yes	Go to the next step.
20		No	Repair or replace the malfunctioning part.
21	Is engine compression correct?	Yes	Inspect the valve timing. (See VARIABLE VALVE TIMING ACTUATOR INSPECTION [LF] .)
21	Is engine compression correct?	No	Inspect for causes.
22	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
The following test is for engine running at rough idle with A/C on. If other symptoms exist, go to the next step.

NOTE
The following test is for engine running rough with P/S on. If other symptoms exist, go to the next step.

ENGINE RUNS ROUGH/ROLLING IDLE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Connect the WDS or equivalent to the DLC-2. Access ECT PID. Start and warm up engine to normal operating temperature. Is ECT PID between 82-112°C {180-234°F} ?	Yes	Go to the next step.
1		No	ECT PID is higher than 112°C {234°F}: Go to symptom troubleshooting NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] . ECT PID is less than 82°C {180°F}: Go to symptom troubleshooting NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF] .
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Access and monitor AC_REQ, CPP (MT), CPP/PNP (MT), and TR (AT) PIDs. Are PIDs values normal? (See PCM INSPECTION [LF] .)	Yes	Go to the next step.
3		No	If the AC_REQ PID is not normal: Inspect A/C switch, refrigerant pressure switch, and fan switch, and related wiring harness for vibration or intermittent open/short circuit. If the CPP PID is not normal: Inspect clutch position switch and related wiring harness for vibration or intermittent open/short circuit. If the CPP/PNP PID is not normal: Inspect neutral position switch and related wiring harness for vibration or intermittent open/short circuit. If the TR PID is not normal: Inspect TR switch and related wiring harness for vibration or intermittent open/short circuit.
4	Connect the WDS or equivalent to the DLC-2. Start the engine and idle it. Retrieve any DTCs for EHPAS. Is there any EHPAS DTC displayed?	Yes	DTC is displayed: Go to appropriate DTC inspection.
4		No	No DTC is displayed: Go to the next step.
5	Is there air leakage felt or heard at intake-air system components while racing engine to higher speed?	Yes	Repair or replace parts if necessary.
5		No	Inspect the following: Electronic throttle control system operation Accelerator pedal position sensor
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

FAST IDLE/RUNS ON DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Does the engine idle roughly?	Yes	Go to symptom troubleshooting "No.8 Engine runs rough/rolling idle". (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [LF] .)
1	Does the engine idle roughly?	No	Go to the next step.
2	Turn off the A/C switch and fan switch. Does the A/C magnetic clutch engage?	Yes	Go to 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 [LF] .)
2		No	Go to the next step.
3	Verify the following: Proper routing of and no damage to vacuum lines No air leakage from intake-air system Are all items normal?	Yes	Go to the next step.
3		No	Service if necessary. Repeat Step 3.
4	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
4		No	No DTC is displayed: Go to the next step.
5	Perform the electronic throttle control system operation inspection. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .) Does the electronic throttle control system function properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to electronic throttle control system operation inspection results.
6	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect the evaporative emission control system.
6		No	Go to the next step.
7	Connect the WDS or equivalent to the DLC-2. Access APP1, APP2, TP, MAF and VSS PIDs. Monitor each PID while driving vehicle. (See PCM INSPECTION [LF] .) Are PIDs normal?	Yes	Go to the next step.
7		No	APP1, APP2 PIDs: Inspect the accelerator pedal position sensor. TP PID: Inspect TP sensor. MAF PID: Inspect MAF sensor. VSS PID: Inspect VSS.
8	Access and monitor BOO, CPP (MT), CPP/PNP (MT), and TR (AT) PIDs. Are PIDs values normal? (See PCM INSPECTION [LF] .)	Yes	Go to the next step.
8		No	If the BOO PID is not normal: Inspect brake switch, and related wiring harness for vibration or intermittent open/short circuit. If the CPP PID is not normal: Inspect clutch position switch and related wiring harness for vibration or intermittent open/short circuit. If the CPP/PNP PID is not normal: Inspect neutral position switch and related wiring harness for vibration or intermittent open/short circuit. If the TR PID is not normal: Inspect TR switch and related wiring harness for vibration or intermittent open/short circuit.
9	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM INSPECTION [LF] .)

LOW IDLE/STALLS DURING DECELERATION DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Verify the following: Vacuum connection Air cleaner element No air leakage from intake-air system No restriction of intake-air system Proper sealing of intake manifold and components attached to intake manifold: such as EGR valve Ignition wiring Fuel quality (such as proper octane, contamination, winter/summer blend) Electrical connections Smooth operation of throttle valve Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Is engine overheating?	Yes	Go to symptom troubleshooting NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] .
3	Is engine overheating?	No	Go to the next step.
4	Connect the WDS or equivalent to the DLC-2. Access APP1, APP2, RPM, VPWR, MAF, TP and VSS PIDs. Drive the vehicle with monitoring PIDs. Are PIDs within specifications? (See PCM INSPECTION [LF] .)	Yes	Go to the next step.
4		No	APP1, APP2 PIDs: Inspect if output signal from accelerator pedal position sensor changes smoothly. RPM PID: Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit. VPWR PID: Inspect for open circuit intermittently. MAF PID: Inspect for open circuit of the MAF sensor and related wiring harness intermittently. TP PID: Inspect if output signal from TP sensor changes smoothly. VSS PID: Inspect for open circuit of VSS and related wiring harness intermittently.
5	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
5		No	Replace the malfunctioning part.
6	Inspect the spark plug conditions. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector. Spark plug is grayish white: Inspect the fuel injector for clogging.
6		No	Install the spark plugs on original cylinders. Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
8	Perform the electronic throttle control system operation inspection. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .) Does the electronic throttle control system function properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to electronic throttle system operation inspection results.
9	Visually inspect deformed exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
9		No	Go to the next step.
10	Install fuel pressure gauge between the fuel pipe and fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position. Is fuel line pressure correct with ignition switch to ON position? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
10		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
11	Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is fuel line pressure held after ignition switch is turned off? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
11		No	Inspect the fuel injector. If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
12	NOTE: The following test is for engine stall with the A/C on. If other symptom exists, go to the next step. Connect a pressure gauge to A/C low and high pressure side lines.Turn the A/C on and measure low side and high side pressure.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK .)	Yes	Go to the next step.
12		No	If the A/C is always on, go to 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 [LF] .) For other symptoms, inspect the following: Refrigerant charging amount Condenser fan operation
13	NOTE: The following test should be performed for symptom with cruise control ON. If other symptoms exist, go to the next step. Inspect cruise control system.Is cruise control system normal?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part.
14	Inspect the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [LF] .) Is the front HO2S normal?	Yes	Go to the next step.
14		No	Replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF] .)
15	Inspect the evaporative purge hose between the fuel tank and the purge valve. Does fuel flow into evaporative purge hose?	Yes	Inspect the check valve (two-way). (See FUEL TANK INSPECTION [LF] .)
15		No	Go to the next step.
16	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Go to the next step. Inspect if the purge solenoid valve is stuck open mechanically. Inspect the evaporative emission control system.
16		No	Go to the next step.
17	Visually inspect the CMP sensor and projections of camshaft pulley. Are CMP sensor and projections of camshaft pulley normal?	Yes	Go to the next step.
17		No	Replace the malfunctioning part.
18	Inspect the EGR system. (See EGR CONTROL SYSTEM INSPECTION .) Is the EGR system normal?	Yes	Go to the next step.
18		No	Replace the malfunctioning part.
19	Is the engine compression correct?	Yes	Inspect the following: Valve timing Internal transaxle part (AT) Clutch (MT) EGR valve (mechanical stuck) Engine mounts Check valve (two-way)
19	Is the engine compression correct?	No	Inspect for cause.
20	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
The following test is for engine stall with the A/C on. If other symptom exists, go to the next step.

NOTE
The following test should be performed for symptom with cruise control ON. If other symptoms exist, go to the next step.

ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Verify the following: Vacuum connection Restriction in intake-air system (such as air cleaner element, fresh air duct) No air leakage from intake-air system No restriction of intake-air system Proper sealing of intake manifold and components attached to intake manifold; such as EGR valve Fuel quality (such as proper octane, contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	DTC is displayed: Go to the next step.
3	Is the engine overheating?	Yes	Go to symptom troubleshooting NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [LF] .
3	Is the engine overheating?	No	Go to the next step.
4	Connect the WDS or equivalent to the DLC-2. Access APP1, APP2, RPM, MAF, TP, IAT and VSS PIDs. Drive vehicle while monitoring PIDs. Are PIDs within specifications? (See PCM INSPECTION [LF] .)	Yes	Go to the next step.
4		No	APP1, APP2 PIDs: Inspect if output signal accelerator pedal position sensor changes smoothly. RPM PID: Inspect CKP sensor and related wiring harness for vibration or intermittent open/short circuit or both. MAF PID: Inspect for intermittent open circuit of MAF sensor and related wiring harness. TP PID: Inspect if output signal TP sensor changes smoothly. IAT PID: Inspect for air suction in intake-air system. If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses. VSS PID: Inspect for intermittent open circuit of VSS and related wiring harness.
5	Visually inspect the CKP sensor and teeth of crankshaft pulley. Are the CKP sensor and teeth of crankshaft pulley normal?	Yes	Go to the next step.
5		No	Replace the malfunctioning part.
6	Inspect the spark plug condition. Is spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect the fuel injector for fuel leakage. Inspect spark plug and high-tension lead. Spark plug is grayish white: Inspect the fuel injector for clogging.
6		No	Install the spark plugs on original cylinders. Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
7	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace PCV valve.
8	Perform electronic throttle control system operation inspection. (See ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION .) Does electronic throttle control system function properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to electronic throttle control system operation inspection results.
9	Visually inspect deformed exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the suspected part.
9		No	Go to the next step.
10	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position. Is fuel line pressure correct with ignition switch to ON position? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
10		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
11	Inspect variable intake air control operation. (See VARIABLE INTAKE AIR CONTROL OPERATION INSPECTION .) Does VIS function properly?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning part.
12	NOTE: The following test is for engine stalling with the A/C on concern. If other symptoms exist, go to the next step. Connect pressure gauge to the A/C low and high side pressure lines.Turn the A/C on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK .)	Yes	Go to the next step.
12		No	If A/C is always on, go to 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 [LF] .) For other symptoms, inspect the following: Refrigerant charging amount Condenser fan operation
13	Inspect for A/C cut-off operation. (See A/C Cut-off Control System Inspection .) Does the A/C cut-off function properly?	Yes	Go to the next step.
13		No	Inspect A/C cut-off system components.
14	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect if purge solenoid valve is stuck open mechanically. Inspect the evaporative emission control system. (See PURGE CONTROL SYSTEM INSPECTION .)
14		No	Go to the next step.
15	Visually inspect the CMP sensor and projections of camshaft pulley. Are the CMP sensor and projections of camshaft pulley normal?	Yes	Go to the next step.
15		No	Replace the malfunctioning part.
16	Inspect EGR system. (See EGR CONTROL SYSTEM INSPECTION .) Is EGR system normal?	Yes	Go to the next step.
16		No	Replace the malfunctioning part according to EGR control system operation inspection results.
17	Inspect the variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
17		No	Repair or replace the malfunctioning part according to variable valve timing control system inspection results.
18	Is the engine compression correct?	Yes	Inspect the following: Valve timing Internal transaxle components (AT) Clutch (MT) Brake system for dragging
18	Is the engine compression correct?	No	Inspect for cause.
19	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
The following test is for engine stalling with the A/C on concern. If other symptoms exist, go to the next step.

LACK/LOSS OF POWER-ACCELERATION/CRUISE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Connect the WDS or equivalent to the 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 the cooling system for cause of overheating.
2	Connect the WDS or equivalent to the DLC-2. Access IAT and MAF PIDs. Monitor each PID. (See PCM INSPECTION [LF] .) Are PIDs normal?	Yes	Go to the next step.
2		No	IAT PID : Inspect IAT sensor MAF PID : Inspect MAF sensor
3	Connect the WDS or equivalent to the DLC-2. Turn the ignition switch to the ON position (engine off). Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
3		No	No DTC is displayed: Go to the next step.
4	Is engine compression correct?	Yes	Go to the next step.
4	Is engine compression correct?	No	Inspect for cause.
5	Install fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Inspect the ignition timing.
5		No	Low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
6	Inspect the knock sensor. Is the knock sensor normal?	Yes	Inspect ignition timing.
6	Inspect the knock sensor. Is the knock sensor normal?	No	Replace the knock sensor.
7	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

KNOCKING/PINGING-ACCELERATION/CRUISE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Air cleaner element for contamination ATF level (AT) Fuel quality Coolant level Brake dragging Clutch slippage (MT) Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Access ECT PID. Drive vehicle while monitoring PID. (See PCM INSPECTION [LF] .) Is PID within specification?	Yes	Go to the next step.
3		No	Inspect for coolant leakage, cooling fan and condenser fan operations or thermostat operation.
4	Perform the spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to spark test result.
5	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
5		No	Low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
6	Inspect for variable valve timing control system operation. (See VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION INSPECTION .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part.
7	Inspect for the variable intake air control operation. (See VARIABLE INTAKE AIR CONTROL OPERATION INSPECTION .) Does variable intake air control function properly?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning part.
8	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
8	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
9	Visually inspect the exhaust system part. Is there any deformed exhaust system?	Yes	Replace the suspected part.
9		No	Go to the next step.
10	Inspect for contaminated MAF sensor. Is there any contamination?	Yes	Go to the next step.
10		No	Inspect for cause.
11	Inspect the MAF sensor for contamination. Is there any contamination?	Yes	Replace MAF sensor.
11		No	Go to the next step.
12	Is engine compression correct?	Yes	Inspect the valve timing.
12	Is engine compression correct?	No	Inspect for cause.
13	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

POOR FUEL ECONOMY DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Vacuum lines for leakage or blockage Electrical connections Proper maintenance schedule followed Intake-air system and air cleaner element concerns: obstructions, leakage or dirtiness Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Is any other driveability concern present?	Yes	Go to appropriate symptom troubleshooting.
3	Is any other driveability concern present?	No	Go to the next step.
4	Connect the WDS or equivalent to the DLC-2. Access ECT PID. Warm up the engine and idle it. Verify ECT PID is correct. (See PCM INSPECTION [LF] .) Is ECT PID correct?	Yes	Go to the next step.
4		No	Inspect for coolant leakage, cooling fan and condenser fan operation or thermostat operation.
5	Inspect fuel-filler cap. (See FUEL-FILLER CAP INSPECTION [LF] .) Is there any leakage at fuel-filler cap?	Yes	Replace the fuel-filler cap.
5		No	Go to the next step.
6	Inspect the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [LF] .) Is front HO2S normal?	Yes	Go to the next step.
6		No	Replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF] .)
7	Perform spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning part according to spark test result.
8	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
8		No	Low: Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
9	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
9	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
10	Inspect for fuel saturation inside charcoal canister. Is excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister.
10		No	Inspect the fuel tank vent system. Then, go to the next step. (See FUEL TANK INSPECTION [LF] .)
11	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace the part.
11		No	Go to the next step.
12	Inspect the three-way catalytic converter. (See EXHAUST SYSTEM INSPECTION [LF] .) Is the three-way catalytic converter normal?	Yes	Inspect the EGR system. (See EGR CONTROL SYSTEM INSPECTION .)
12		No	Replace the three-way catalytic converter.
13	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

EMISSION COMPLIANCE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
1	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
2	Inspect for the following: External leakage Proper dipstick Proper engine oil viscosity Are all items normal?	Yes	Inspect the internal engine parts such as valves, valve guides, valve stem seals, cylinder head drain passage, and piston rings.
2		No	Service if necessary. Repeat Step 2.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

HIGH OIL CONSUMPTION/LEAKAGE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: Engine coolant level Coolant leakage Water and anti-freeze mixture Radiator condition Collapsed or restricted radiator hoses Radiator pressure cap Overflow system Fan rotational direction Fuses Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Go to the next step.
3	Start the engine and idle it. Turn the A/C switch on and set blower fan to any speed. Does the A/C compressor engage?	Yes	Go to Step 5.
3		No	Inspect for the following and repair or replace if necessary: Refrigerant charging amount Open circuit in wiring harness between A/C relay and PCM terminal 11 Seized A/C magnetic clutch A/C magnetic clutch malfunction If all items are normal, go to the next step.
4	Connect the WDS or equivalent to DLC-2. Access AC_REQ PID. Start the engine and idle it. Turn the A/C switch and fan switch on. Does AC_REQ PID read on?	Yes	Go to the next step.
4		No	Inspect the following: Refrigerant pressure switch operation The A/C switch is stuck open. Open or short circuit between refrigerant pressure switch and PCM terminal 1AU Open circuit of blower motor fan switch and resistor (if blower motor does not operate) The evaporator temperature sensor and A/C amplifier
5	Inspect cooling fan control system operation. (See COOLING FAN CONTROL SYSTEM INSPECTION .) Does the cooling fan control system function properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part.
6	Is the drive belt normal?	Yes	Go to the next step.
6	Is the drive belt normal?	No	Replace the drive belt.
7	Is there leakage around the heater unit in passenger compartment?	Yes	Inspect and service heater for leakage.
7		No	Go to the next step.
8	Is there leakage at the coolant hoses and/or radiator?	Yes	Replace the malfunctioning part.
8	Is there leakage at the coolant hoses and/or radiator?	No	Go to the next step.
9	Cool down the engine. Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [LF] .) (See THERMOSTAT INSPECTION [LF] .) Is thermostat normal?	Yes	The engine coolant temperature and thermostat are normal, inspect engine block for leakage or blockage.
9		No	Access ECT PID. Inspect for both ECT PID and temperature gauge readings. If temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor. If temperature gauge on instrument cluster indicates overheating but ECT PID is normal, inspect temperature gauge and heat gauge unit.
10	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

COOLING SYSTEM CONCERNS-OVERHEATING DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Is customer complaint "Lack of passenger compartment heat" only?	Yes	Inspect A/C and heater system.
1		No	Go to the next step.
2	Does the engine speed continue at fast idle?	Yes	Go to symptom troubleshooting "No.9 Fast idle/runs on". (See NO.9 FAST IDLE/RUNS ON [LF] .)
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [LF] .) (See THERMOSTAT INSPECTION [LF] .) Is thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat.
4	Inspect cooling fan control system operation. (See COOLING FAN CONTROL SYSTEM INSPECTION .) Does the cooling fan control system function properly?	Yes	Access ECT PID. Inspect for both ECT PID and temperature gauge on instrument cluster readings. If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not the same as temperature gauge reading, inspect the ECT sensor. If the temperature gauge on the instrument cluster indicates cold range but ECT PID is normal, inspect the temperature gauge and heat gauge unit.
4		No	Repair or replace the malfunctioning part.
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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. (See PCM REMOVAL/INSTALLATION [LF] .)

COOLING SYSTEM CONCERNS-RUNS COLD DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	What color is smoke coming from the exhaust system?	Blue	Burning oil is indicated. Go to the next step.
		White	Water in combustion is indicated. Go to Step 3.
		Black	Rich fuel mixture is indicated. Go to Step 4.
2	Remove and shake the PCV valve. Does the PCV valve rattle?	Yes	Inspect for the following: Damaged valve guide, stems or valve seals Blocked oil drain passage in cylinder head Piston ring is not seated, seized or worn. Damaged cylinder bore If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
2	Remove and shake the PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
3	Does the cooling system hold pressure?	Yes	Inspect for the following: Cylinder head gasket leakage Intake manifold gasket leakage Cracked or porous engine block If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
3	Does the cooling system hold pressure?	No	Inspect for cause.
4	Inspect for the following: Air cleaner restriction Collapsed or restricted intake-air system Restricted fuel return line Are all 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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
5		No	No DTC is displayed: Go to the next step.
6	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
6		No	Low: Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
7	Perform the spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [LF] .)
7		No	Repair or replace the malfunctioning part according to spark test result.
8	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

EXHAUST SMOKE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start engine and idle it. Measure fuel line pressure during idle. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
1		No	Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
2	Inspect for blockage/restriction or open circuit in wiring harness between the engine vacuum port and the charcoal canister. Inspect for blockage in fuel tank vent system. Is malfunction indicated?	Yes	Replace vacuum hose.
2		No	Go to the next step.
3	Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION [LF] .) Is the solenoid operating properly?	Yes	Go to the next step.
3		No	Replace the purge solenoid valve. (See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [LF] .)
4	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
4		No	No DTC is displayed: Inspect charcoal canister for fuel saturation. If excess amount of liquid fuel is present, replace the charcoal canister.
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

FUEL ODOR (IN ENGINE COMPARTMENT) DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect for the followings: Engine oil level Drive belt tension Splash shield or under cover looseness Generator installation (alignment)
1	Is a squealing, click or chirping sound present?	No	Go to the next step.
2	Is a rumbling or grinding noise present?	Yes	Inspect for the followings: Drive belt tension P/S fluid level
2	Is a rumbling or grinding noise present?	No	Go to the next step.
3	Is a rattling noise present?	Yes	Inspect rattling location for loose parts.
3	Is a rattling noise present?	No	Go to the next step.
4	Is a hissing noise present?	Yes	Inspect for the following: Vacuum leakage Spark plug looseness Intake-air system leakage
4	Is a hissing noise present?	No	Go to the next step.
5	Is a rapping or roar noise present?	Yes	Inspect looseness for followings: Dynamic dumper Intake-air system Exhaust system
5	Is a rapping or roar noise present?	No	Go to the next step.
6	Is a knocking noise present?	Yes	Go to symptom troubleshooting "No.13 Knocking/pinging". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [LF] .)
6	Is a knocking noise present?	No	If the noise comes from the engine internal, inspect for friction gear, timing chain or MLA noise.
7	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

ENGINE NOISE DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following components for loose attaching bolts or worn parts: Cooling fan Drive belt and pulleys Generator Engine mounts Exhaust system mounts All items normal?	Yes	Inspect the following systems: Wheels AT Driveline Suspension
1		No	Readjust or retighten engine mount installation position. Service if necessary for other parts.
2	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

VIBRATION CONCERNS (ENGINE) DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Go to the next step.
2	Disconnect A/C compressor connector. Start engine and turn A/C switch on. Is there correct voltage at A/C compressor magnetic clutch terminal? Specification 10.5 V or more	Yes	Inspect for GND condition of magnetic clutch on A/C compressor. If GND condition is normal, inspect for open circuit magnetic clutch coil.
2		No	Go to the next step.
3	Disconnect refrigerant pressure switch connector. Connect jumper wiring between A/C high pressure switch terminal. Connect jumper wiring between refrigerant pressure switch terminal. Turn the ignition switch to the ON position. Turn A/C switch on and set blower fan to any speed. Does A/C work?	Yes	Inspect refrigerant pressure switch operation. If switch is normal, go to the next step.
3		No	Inspect for the following: A/C switch is stuck open. Open circuit in wiring harness between refrigerant pressure switch and PCM terminal 1AU Open circuit in wiring harness between blower motor fan switch and resistor (if blower motor does not operate) Evaporator temperature sensor and A/C amplifier
4	Remove jumper wiring from the switch connector. Reconnect connector to refrigerant pressure switch. Start the engine and turn the A/C switch on. Does the fan operate?	Yes	Inspect whether A/C relay is stuck open. Replace if necessary.
4		No	Inspect the following and repair or replace if necessary: Refrigerant charging amount A/C compressor for seizure
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

A/C DOES NOT WORK SUFFICIENTLY DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Go to the next step.
2	Start the engine and idle it. Turn the A/C switch on. Remove the A/C relay. Does the A/C magnetic clutch disengage?	Yes	Inspect for the following: A/C relay is stuck closed. Short to GND in wiring harness between A/C relay and PCM terminal 11. If both items normal, go to the next step.
2		No	Inspect if circuit between the A/C relay and magnetic clutch shorts to battery power circuit. If the circuit is normal, inspect the magnetic clutch for stuck engagement or clearance.
3	Disconnect refrigerant pressure switch connector. Start the engine and turn A/C switch on. NOTE: A/C should not work when disconnecting connector. If A/C remains working, short to GND circuit may be present. Does the A/C remain working?	Yes	Inspect for short to GND in wiring harness between refrigerant pressure switch and PCM terminal 1AU.
3		No	Go to the next step.
4	Reconnect refrigerant pressure switch connector. Turn off A/C switch. NOTE: A/C should not work when turning A/C switch off. If A/C remains working, short to GND circuit may be present. Does A/C remain working?	Yes	Inspect following: Short to GND in wiring harness between A/C switch and A/C amplifier Short to GND circuit between A/C amplifier and refrigerant pressure switch
4		No	Inspect whether A/C switch is stuck closed.
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

NOTE
A/C should not work when disconnecting connector. If A/C remains working, short to GND circuit may be present.

NOTE
A/C should not work when turning A/C switch off. If A/C remains working, short to GND circuit may be present.

A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Does A/C compressor disengage when the A/C switch is turned off?	Yes	Go to the next step.
1		No	Go to symptom troubleshooting NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [LF] .
2	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
2		No	No DTC is displayed: Inspect accelerator pedal position sensor.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Are any driveability or exhaust smoke concerns present?	Yes	Go to the appropriate flow table.
1	Are any driveability or exhaust smoke concerns present?	No	Go to the next step.
2	Inspect the following: Electrical connections Vacuum lines Fuel quality Are all items normal?	Yes	Go to the next step.
2		No	Service if necessary. Repeat Step 2.
3	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
3		No	No DTC is displayed: Go to the next step.
4	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start engine and idle it. Is fuel line pressure correct at idle? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
4		No	Low: Inspect fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
5	Inspect the charcoal canister for fuel saturation. Is excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister.
5		No	Inspect the fuel tank vent system. If the fuel tank vent system is normal, suggest trying a different brand since sulphur content can vary in different fuels. If the fuel tank vent system is not normal, repair or replace the malfunctioning part.
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

EXHAUST SULPHUR SMELL DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION		ACTION
1	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Go to the next step.
2	Remove the fuel-filler pipe. Make sure the nonreturn valve is installed properly. Inspect nonreturn valve operation. Is the nonreturn valve normal?	Yes	Inspect for the following: Improper use of fuel nozzle Inadequate fuel filling speed
2		No	Nonreturn valve is installed improperly: Reinstall nonreturn valve to proper position. Nonreturn valve does not operate properly: Replace nonreturn valve.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

FUEL REFILL CONCERNS DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION		ACTION
1	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	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [LF] .)
1		No	No DTC is displayed: Go to the next step.
2	Remove the fuel-filler pipe. Make sure the nonreturn valve is installed properly. Inspect nonreturn valve operation. Is the nonreturn valve normal?	Yes	Inspect for the following: Improper use of fuel nozzle Fuel is not inserted correctly. Inspect fuel shut-off valve.
2		No	Nonreturn valve is installed improperly: Reinstall the nonreturn valve to proper position. Nonreturn valve does not operate properly: Replace the nonreturn valve.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

FUEL FILLING SHUT OFF CONCERNS DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION	RESULTS	ACTION
1	Remove all the spark plugs. Inspect spark plug condition. Is spark plug condition normal?	Yes	Troubleshooting completed.
1		No	Specific plug is wet or covered with carbon: Go to the next step. Specific plug looks grayish white: Go to Step 7. All plugs are wet or covered with carbon: Go to Step 9. All plugs look grayish white: Go to Step 15.
2	Are the spark plug wet/covered with carbon by the engine oil?	Yes	Inspect all areas related to oil, working up and down.
2		No	Go to the next step.
3	Inspect the spark plug for the following: Cracked insulator Heat range Air gap Worn electrode Is the spark plug normal?	Yes	Go to the next step.
3		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [LF] .)
4	Inspect compression pressure at suspected malfunctioning cylinder. Is compression pressure correct? (See COMPRESSION INSPECTION [LF] .)	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part.
5	Install all spark plugs. Perform the spark test at suspected malfunctioning cylinder. Is strong blue spark visible? (Compare with normal cylinder.)	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part.
6	Install the fuel pressure gauge between fuel filter and fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position (Engine off). Is the fuel line pressure correct with the ignition switch at ON? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Inspect fuel injector for the following: Open or short circuit in injector Leakage Injection volume
6		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
7	Inspect the spark plug for the following. Heat range Air gap Is the spark plug normal?	Yes	Go to the next step.
7		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [LF] .)
8	Remove the suspected fuel injector. Inspect the following: Resistance (See FUEL INJECTOR INSPECTION [LF] .) Fuel injection volume (See FUEL INJECTOR INSPECTION [LF] .) Are all above items normal?	Yes	Inspect for open circuit in wiring harness between fuel injector connector terminal B and PCM at the following terminals: For No.1 cylinder: 2BB For No.2 cylinder: 2BC For No.3 cylinder: 2BD For No.4 cylinder: 2AZ
8		No	Replace the fuel injector.
9	Is the air cleaner element free of clogging?	Yes	Go to the next step.
9	Is the air cleaner element free of clogging?	No	Replace the air cleaner element.
10	Perform the spark test. (See SPARK TEST .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning part.
11	Install the fuel pressure gauge between the fuel filter and fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position (Engine off). Is the fuel line pressure correct with ignition switch at ON? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Go to the next step.
11		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
12	Inspect the following PIDs: ECT O2S11 (When engine can be started.) O2S12 (When engine can be started.) MAF (See PCM INSPECTION [LF] .) Are PIDs normal?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part.
13	Perform the purge control inspection. (When engine can be started.) (See PURGE CONTROL SYSTEM INSPECTION .) Is the purge control correct?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part.
14	Perform compression inspection. (See COMPRESSION INSPECTION [LF] .) Is compression correct?	Yes	Visually inspect for deformed exhaust system part.
14		No	Repair or replace the malfunctioning part.
15	When the engine cannot be started, inspect the intake-air system for air leakage. When the engine can be started, perform intake manifold vacuum inspection. Is air sucked in from intake-air system?	Yes	Repair or replace the malfunctioning part.
15		No	Go to the next step.
16	Install the fuel pressure gauge between the fuel filter and the fuel distributor. Short check connector terminal F/P to body GND using a jumper wiring. Turn the ignition switch to the ON position (Engine off). Is fuel line pressure correct with the ignition switch at ON? (See FUEL LINE PRESSURE INSPECTION [LF] .)	Yes	Inspect the following PIDs: ECT O2S11 O2S12 MAF (See PCM INSPECTION [LF] .) Inspect PCM GND condition.
16		No	Zero or low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF] .)
17	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [LF] .) 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 the PCM. (See PCM REMOVAL/INSTALLATION [LF] .)

SPARK PLUG CONDITION DIAGNOSTIC PROCEDURE TABLE

Input Signal System Inspection Procedure

Find an irregular signal. (See «FINDING IRREGULAR SIGNALS»(ref-244450-S03521135462006092400000) .)
Locate source. (See «LOCATING THE SOURCE OF UNUSUAL SIGNALS»(ref-244450-S11473088552006092400000) .)
Repair or replace the malfunctioning part.
Confirm that the irregular signal is no longer detected.

Standard Power Supply System Inspection For Variable Resistance Type 1

Confirm that the #3 terminal is at 5 V . If the measured voltage on the #3 terminal is 5 V , inspect the following points on the sensor connector. If there is no problem, inspect for the following: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) If the #3 terminal measures other than 5 V , inspect for the following: Open or short circuit in wiring harness Harness/pin crimp is loose or disconnected.

GND System Inspection For Variable Resistance Type 1

Confirm that terminal sensor #5 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not, inspect for the following: Open or short circuit in wiring harness Female terminal opening is loose causing an open or short circuit in wiring harness Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected.

Scheme 10

Scheme 10: GND System Inspection For Variable Resistance Type 2

Confirm that terminal sensor #4 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not at 0 V , inspect for the following: Open circuit in wiring harness Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected.

Input Signal System Inspection For Variable Resistance Type 2

When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the WDS or equivalent monitor voltage are the same, proceed to the next step. If there is a difference of 0.5 V or more , inspect for the following points concerning the PCM connector: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected.
Measure the #2 sensor terminal voltage. If there is a 0 V or more difference between the sensor and the WDS or equivalent voltages, inspect the wiring harness for open or short circuits. If the sensor and the WDS or equivalent voltages are the same, inspect the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected. If there are no problems, proceed to next investigation below.

Electrical Supply System Inspection For Variable Resistance Type 2

Confirm that the sensor #3 terminal is B+ . If the measured voltage on the #3 terminal is B+ , inspect the following points on the sensor connector. If there is no problem, inspect for the following: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) If the #3 terminal measures other than B+ , inspect the following: Open or short circuit in wiring harness Harness/pin crimp is loose or disconnected.

Scheme 11

Scheme 11: Input Signal System Inspection For Thermistor Type

When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the WDS or equivalent monitor voltage are the same, proceed to the next step. If there is a difference of 0.5 V or more , inspect the following points concerning the PCM connector: Female terminal opening loose Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected.
Measure the #2 sensor terminal voltage. If there is a 0.5 V or more difference between the sensor and the WDS or equivalent voltages, inspect the wiring harness for open or short circuits. If the sensor and the WDS or equivalent voltages are the same, inspect the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected. If there are no problems, proceed to next investigation below.

GND System Inspection For Thermistor Type

Confirm that terminal sensor #3 is at 0 V . If it is at 0 V , inspect the sensor. If necessary, replace the sensor. If not, inspect for the following: Open circuit in wiring harness Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected.

Intake Manifold Vacuum Inspection

Verify that the intake air hoses are installed securely.
Disconnect the vacuum hose connecting the intake manifold and the purge solenoid valve (purge solenoid valve side) and install the vacuum gauge.
Warm up the engine.
Measure the intake manifold vacuum while idling (no load) using the vacuum gauge. (See «INTAKE MANIFOLD VACUUM INSPECTION [LF]»(ref-244455-S27476421482006092400000) .) If not within the specification, perform the following inspections. Compression pressure (See «COMPRESSION INSPECTION [LF]»(ref-244453-S01263720752006092400000) .) Air intake Each hose installation part Throttle body installation part Fuel injector installation part PCV valve installation part Dynamic chamber installation port Intake manifold installation part

Engine Coolant Temperature Compensation Inspection

Connect the WDS or equivalent to the DLC-2.
Access the following PIDs: ECT IAT RPM
Verify that the engine is cold, then start the engine.
Verify that the engine speed decreases as the engine warms up If the engine speed does not decrease or decreases slowly, inspect the following: ECT sensor and related wiring harness (See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [LF]»(ref-244452-S21398329352006092400000) .) Electronic throttle body and related wiring harness (See «THROTTLE BODY INSPECTION [LF]»(ref-244455-S15430747592006092400000) .)

Load Compensation Inspection

Start the engine and idle it.
Connect the WDS or equivalent to the DLC-2.
Verify that P0506, P0507, or P0511 is not displayed. If P0506, P0507 or P0511 are displayed, perform DTC inspection. (See «DTC TABLE [LF]»(ref-244449-S40344338372006092400000) .)
Access the RPM PID. NOTE: Excludes temporary idle speed drop just after the loads are turned on.
Verify that the engine speed is within the specification under each load condition. (See «ENGINE TUNE-UP [LF]»(ref-244453-S25482879702006092400000) .) If load condition is not as specified, inspect the following: A/C switch and related wiring harness (See «CLIMATE CONTROL UNIT INSPECTION»(ref-244473-S36542024872006092400000) .) Fan switch and related wiring harness (See «CLIMATE CONTROL UNIT INSPECTION»(ref-244473-S36542024872006092400000) .)

Throttle Position (TP) Sweep Inspection

Connect the WDS or equivalent to the DLC-2.
Turn the ignition switch to the ON position.
Verify that none of the following DTC are displayed: P0122, P0123, P0222, P0223, P0638, P2101, P2107, P2108, P2109, P2112, P2119, P2122, P2123, P2127, P2128, P2135, P2138 If any one DTC is displayed, perform DTC inspection.
Access TP_REL PID.
Verify that the PID reading is within the CTP value. (See «PCM INSPECTION [LF]»(ref-244452-S30974371722006092400000) .) If the PID reading is out of range, perform the following: Remove the air duct from the throttle valve body. Verify that the throttle valve opens when the accelerator pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.
Gradually depress the throttle pedal and verify that the PID reading increases accordingly. If the PID reading drops momentarily, inspect the following: Throttle position sensor
Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See «PCM INSPECTION [LF]»(ref-244452-S30974371722006092400000) .) If the PID reading is out of range, perform the followings: Remove the air duct from throttle valve body. Verify that the throttle valve opens when throttle pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.

Fuel Cut Control System Inspection

Note. This inspection has to perform after the Fuel Injector Operation Inspection.

Fuel Pump Control System Inspection

Crank the engine and verify that fuel pump relay operation sound is heard.
If operation sound is not heard, inspect the following: Fuel pump relay (See «RELAY INSPECTION»(ref-244461-S14741832262006092400000) .) Wiring harness and connectors (Main relay-fuel pump relay-PCM terminal 1H

Spark Test

Disconnect the fuel pump relay.
Verify that each ignition coil and connector is connected properly.
Inspect the ignition system in the following procedure. WARNING: High voltage in the ignition system can cause strong electrical shock which can result in serious injury. Avoid direct contact to the vehicle body during the following spark test.

STEP	INSPECTION		ACTION
1	Disconnect the ignition coil from the spark plugs. Remove the spark plugs. Reconnect the spark plugs to the ignition coil. Ground the spark plugs to engine. Is strong blue spark visible at each cylinder while cranking?	Yes	Ignition system is normal.
1		No	Some cylinders do not spark: Go to the next step. All cylinders do not spark: Go to Step 4.
2	Inspect the spark plugs for damage, wear, carbon deposits and proper plug gap. Are the spark plugs normal?	Yes	Go to the next step.
2		No	Replace spark plugs, then go to Step 1.
3	Inspect the following wiring harnesses for open or short: Ignition coil No.1 terminal C-PCM terminal 2BA Ignition coil No.2 terminal C-PCM terminal 2AW Ignition coil No.3 terminal C-PCM terminal 2AX Ignition coil No.4 terminal C-PCM terminal 2AT Are the wiring harnesses normal?	Yes	Inspect and replace the ignition coil. (See IGNITION COIL INSPECTION [LF] .)
3		No	Repair or replace the malfunctioning part, then go to Step 1.
4	Measure the voltage at terminal A in each ignition coils. Is the voltage B+ ?	Yes	Go to the next step.
4		No	Inspect power supply circuit of ignition coils.
5	Verify continuity between each ignition coils terminal B and battery negative post. Is there any continuity?	Yes	Go to the next step.
5		No	Inspect GND circuit of ignition coils.
6	Does the PCM connector or ignition coil connectors have poor connection?	Yes	Repair or replace the connector, then go to Step 1.
6		No	Go to the next step.
7	Are the following parts normal? CKP sensor and crankshaft pulley	Yes	Inspect for open or short circuit in wiring harness and connector of CKP sensor.
7		No	Repair or replace the malfunctioning part, then go to Step 1.

IGNITION SYSTEM INSPECTION TABLE

A/C Cut-off Control System Inspection

Start the engine.
Turn the A/C switch and the fan switch on.
Verify that the A/C compressor magnetic clutch actuates. If it does not actuate, go to symptom troubleshooting «NO.23 A/C DOES NOT WORK SUFFICIENTLY [LF]»(ref-244450-S29761768222006092400000) .
Fully open the throttle valve and verify that the A/C compressor magnetic clutch does not actuate for 2-5 s. If it actuates, inspect as follows: A/C relay Open or short to GND circuit in wiring harness and connectors (Ignition switch-A/C relay-PCM terminal 11) A/C related parts APP1, APP2 PIDs

Evaporative Emission (EVAP) System Leak Inspection

To verify that the problem has been fixed properly after repairs, the run drive cycle or EVAP system leak inspection must be performed.

EVAP System Leak Inspection Using WDS or Equivalent

Note. EVAP system test outline The EVAP system test, which can substituted for the run drive cycle as an EVAP control system repair confirmation method, can be done while operating the WDS in the KOEO (Key On Engine Off) condition instead of actually driving the vehicle.

Evaporative System Test Procedure

Select the EVAP system test from the toolbox on the WDS display and follow the instructions.
Verify that all of the following PIDs are within the specifications at the pre-test confirmation screen. NOTE: To successfully perform this procedure, all PIDs must be within the following specifications before proceeding to the next step. The PCM will cancel the EVAP system test if the VPWR PID value falls lower than 11.0 V during the test. PID SPECIFICATION PID PID Range BARO 72.2 kPa {543 mmHg, 21.3 inHg} or more FLI 15-85% IAT 5-45°C {41-113°F} VPWR 11.0 V or more
Start the engine.
Drive the vehicle or let the engine idle more than 20 min.
Turn ignition switch off, then turn it to the ON position again (Key On Engine Off).
Press the tick icon to start the test.
Verify that no DTCs present after the completion of the test.

If any test result is indicated with red, diagnose the problem using the following DTC troubleshooting procedure or component inspection procedure.
If any DTCs are detected, diagnose the problem using the appropriate DTC troubleshooting procedure.

Scheme 12

Scheme 12: EVAP System Leak Inspection Using Leak Tester

Scheme 13

Perform the following SST (EVAP System Tester 134-01049) self-test: NOTE: If the tester does not work correctly during the self-test, refer to the tester operators manual for a more detailed self-test procedure. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle valve. Connect the vehicle interface hose (part of the SST ) to the SELF-TEST port located on the control panel. Hand tighten the fitting. (Do not overtighten.) Turn the control valve to the TEST position. The gauge should read 331-381 mm {13-15 in} of water. If the gauge is not reading in this range, adjust the pressure by turning the black knob on the low pressure regulator at the nitrogen bottle. Turn the control valve to the HOLD position. Verify that the gauge holds pressure and that the flow meter reads no flow. If there is no drop in pressure and no flow, the tester passes the self-test. If the gauge leaks down, refer to the tester operators manual.
Connect the SST to the vehicle. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle valve. Remove the fuel-filler cap from the vehicle. If the fuel-filler cap is not a MAZDA part or equivalent, replace it. Connect the receiver assembly ( SST: AKS441130) to the vehicle cap test hose assembly (part of the SST ) and the fuel-filler cap from the vehicle. Connect the cap adaptor ( SST: AKS441131) to the vehicle cap test hose assembly (part of the SST ) and to the fuel-filler neck. Connect the vehicle interface hose (part of the SST ) to the center fitting of the vehicle cap test hose assembly (part of the SST ).
Connect the WDS or equivalent to the DLC-2.
Turn the ignition switch to the ON position (Engine off).
Request the PCM on-board device control (Mode 08) using the WDS or equivalent to close the change-over valve (COV) in the EVAP system leak detection pump. NOTE: The COV is closed for 10 min unless the following any actions are done: The engine is started. The ignition switch is turned off position.
Make sure the control valve on the 134-01049 is in the HOLD position and that the valve on the cylinder of nitrogen gas is open.
Turn the control valve to the open position and let the system fill. You should note a drop in the gauge pressure along with the flow meter being pegged at maximum flow for several minutes depending on how full or empty the fuel tank is, and how long it takes to completely fill and pressurize the evaporative emissions system hoses.
If the gauge and the flow meter do not settle to a measurable level after 2-3 min , then refer to the appropriate service article to verify that the cut or vent valve is properly closed.
Verify the pressure gauge and flow meter reading to determine if there is an evaporative emissions leak: NO EVAPORATIVE LEAK: The flow meter registers "zero flow" and the pressure gauge returns to the pre-set pressure of 356 mm {14 in} of water (H2O). EVAPORATIVE LEAK: The pressure does not return to the preset level of 356 mm {14 in} of water (H2O) when measuring the flow. See "SETTING LEAK STANDARD FOR TESTING" (.020 to .040 inch H2O) of the Evaporative Emissions Tester operators manual (134-01067). NOTE: Turn the control valve to the HOLD position then disconnect the SST.

Symptom Troubleshooting - Engine: Diagnosis Mazda MX-5 NC