Symptom Troubleshooting [Engine Control System [Mzi 3.7 V6]]: Diagnosis

SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6]

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

No.	TROUBLESHOOTING ITEM		DESCRIPTION	REFERENCE
1	Melting of main or other fuses			(See NO.1 MELTING OF MAIN OR OTHER FUSES [MZI 3.7 V6] .)
2	MIL illuminates		The MIL is illuminated incorrectly.	(See NO.2 MIL ILLUMINATES [MZI 3.7 V6] .)
3	Will not crank		The starter does not work.	(See NO.3 WILL NOT CRANK [MZI 3.7 V6] .)
4	Hard to start/long crank/erratic start/erratic crank		The starter cranks engine at normal speed but engine requires excessive cranking time before starting. The battery is in normal condition.	(See NO.4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZI 3.7 V6] .)
5	Engine stalls	After start/at idle	Engine stops unexpectedly.	(See NO.5 ENGINE STALLS-AFTER START/AT IDLE [MZI 3.7 V6] .)
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 [MZI 3.7 V6] .)
7	Slow return to idle		Engine takes more time than normal to return to idle speed.	(See NO.7 SLOW RETURN TO IDLE [MZI 3.7 V6] .)
8	Engine runs rough/rolling idle		Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively. Idle speed is too slow and engine shakes excessively.	(See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI 3.7 V6] .)
9	Fast idle/runs on		The engine speed continues at fast idle after warm-up. The engine runs after the ignition is off.	(See NO.9 FAST IDLE/RUNS ON [MZI 3.7 V6] .)
10	Low idle/stalls during deceleration		Engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.	(See NO.10 LOW IDLE/STALLS DURING DECELERATION [MZI 3.7 V6] .)
11	Engine stalls/quits	Acceleration/cruise	Engine stops unexpectedly at the beginning of acceleration or during acceleration. Engine stops unexpectedly while cruising.	(See NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [MZI 3.7 V6] .)
	Engine runs rough	Acceleration/cruise	Engine speed fluctuates during acceleration or cruising.
	Misses	Acceleration/cruise	Engine misses during acceleration or cruising.
	Buck/jerk	Acceleration/cruise/deceleration	Vehicle bucks/jerks during acceleration, cruising, or deceleration.
	Hesitation/stumble	Acceleration	Momentary pause at beginning of acceleration or during acceleration.
	Surges	Acceleration/cruise	Momentary minor irregularity in engine output.
12	Lack/loss of power	Acceleration/cruise	Performance is poor under load (such as power down when climbing hills).	(See NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZI 3.7 V6] .)
13	Knocking/pinging	Acceleration/cruise	Sound is heard when air/fuel mixture is ignited by something other than spark plug (such as hot spot in combustion chamber).	(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI 3.7 V6] .)
14	Poor fuel economy		Fuel economy is unsatisfactory.	(See NO.14 POOR FUEL ECONOMY [MZI 3.7 V6] .)
15	Emission compliance		Fails emissions test.	(See NO.15 EMISSION COMPLIANCE [MZI 3.7 V6] .)
16	High oil consumption/leakage		Oil consumption is excessive.	(See NO.16 HIGH OIL CONSUMPTION/LEAKAGE [MZI 3.7 V6] .)
17	Cooling system concerns	Overheating	Engine runs at higher than normal temperature/overheats.	(See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .)
18	Cooling system concerns	Runs cold	Engine takes excessive time to reach normal operating temperature.	(See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZI 3.7 V6] .)
19	Exhaust smoke		Blue, black, or white smoke from exhaust system.	(See NO.19 EXHAUST SMOKE [MZI 3.7 V6] .)
20	Fuel odor (in engine compartment)		Gasoline fuel smell or visible leakage.	(See NO.20 FUEL ODOR (IN ENGINE COMPARTMENT) [MZI 3.7 V6] .)
21	Engine noise		Engine noise from under hood.	(See NO.21 ENGINE NOISE [MZI 3.7 V6] .)
22	Vibration concerns (engine)		Vibration from under hood or driveline.	(See NO.22 VIBRATION CONCERNS (ENGINE) [MZI 3.7 V6] .)
23	A/C does not work sufficiently		A/C compressor magnetic clutch does not engage when the A/C switch is turned on.	(See NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZI 3.7 V6] .)
24	A/C is always on or A/C compressor runs continuously		A/C compressor magnetic clutch does not disengage.	(See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .)
25	A/C does not cut off under wide open throttle conditions		A/C compressor magnetic clutch does not disengage under WOT.	(See NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS [MZI 3.7 V6] .)
26	Exhaust sulphur smell		Rotten egg smell (sulphur) from exhaust.	(See NO.26 EXHAUST SULPHUR SMELL [MZI 3.7 V6] .)
27	Fuel refill concerns		Fuel tank is not filled smoothly.	(See NO.27 FUEL REFILL CONCERNS [MZI 3.7 V6] .)
28	Fuel filling shut off concerns		Fuel does not shut off properly.	(See NO.28 FUEL FILLING SHUT OFF CONCERNS [MZI 3.7 V6] .)
29	Spark plug condition		Incorrect spark plug condition.	(See NO.29 SPARK PLUG CONDITION [MZI 3.7 V6] .)
30	ATX concerns	Upshift/downshift engagement	ATX concerns not related to engine performance.	(See SYMPTOM TROUBLESHOOTING ITEM TABLE [AY6A-EL] .)

DIAGNOSTIC INDEX

Scheme 107

Scheme 107: QUICK DIAGNOSTIC CHART [MZI 3.7 V6]

Scheme 108

Scheme 109

Scheme 110

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
1		No	No DTC is displayed: Inspect the instrument cluster operation. (See INSTRUMENT CLUSTER INSPECTION .)
2	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	DETERMINE IF MALFUNCTION CAUSE IS ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM OR OTHER NOTE: The following test should be performed on the advanced keyless entry and push button start 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 and push button start system. Repair or replace the malfunctioning part according to the inspection results.
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS IMMOBILIZER SYSTEM OR OTHER Do the following conditions appear? The engine is not completely started. Security indicator light illuminates or flashes short interval.	Yes	Both conditions appear: Go to Step 5.
2		No	Either or other condition appears: Go to the next step.
3	INSPECT COIL ANTENNA CONNECTOR CONNECTION Is the coil antenna connector securely connected to the coil antenna?	Yes	Go to the next step.
3		No	Connect the coil antenna connector securely. Return to Step 1.
4	DETERMINE IF MALFUNCTION CAUSE IS INSTRUMENT CLUSTER OR OTHER Does the security light flash?	Yes	Go to the next step.
4		No	Inspect the instrument cluster and wiring harness. (See INSTRUMENT CLUSTER INSPECTION .)
5	VERIFY IMMOBILIZER SYSTEM DTC Retrieve the DTC for immobilizer system using the M-MDS. (See DTC INSPECTION [IMMOBILIZER SYSTEM (KEYLESS ENTRY SYSTEM)] .) (See DTC INSPECTION [IMMOBILIZER SYSTEM (ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM)] .) Is there any DTC present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [IMMOBILIZER SYSTEM (KEYLESS ENTRY SYSTEM)] .) (See DTC TABLE [IMMOBILIZER SYSTEM (ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM)] .)
5		No	Go to the next step.
6	INSPECT IMMOBILIZER SYSTEM RELATED CIRCUIT Inspect the following wiring harnesses and connectors: With advanced keyless entry and push button start system: Between coil antenna terminal C and keyless control module terminal 2B Between coil antenna terminal D and keyless control module terminal 2D Between PCM terminal 1AH and keyless control module terminal 2G Between PCM terminal 1AL and keyless control module terminal 2I Without advanced keyless entry and push button start system: Between coil antenna terminal C and instrument cluster terminal 2E Between coil antenna terminal D and instrument cluster terminal 2G Between PCM terminal 1AH and instrument cluster terminal 2X Between PCM terminal 1AL and instrument cluster terminal 2W Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
6		No	Go to the next step.
7	INSPECT POWER SUPPLY Inspect the following: Battery connection Battery condition (See BATTERY INSPECTION [MZI 3.7 V6] .) Fuses (See NO.1 MELTING OF MAIN OR OTHER FUSES [MZI 3.7 V6] .) Transmission in Park or Neutral Is there any malfunction?	Yes	Service if necessary. Repeat Step 7.
7		No	With advanced keyless entry and push button start system: Go to the next step. Without advanced keyless entry and push button start system: Go to Step 19.
8	INSPECT STARTER RELAY Inspect the starter relay. (See RELAY INSPECTION .) Is there any malfunction?	Yes	Replace the starter relay.
8		No	Go to the next step.
9	DETERMINE IF MALFUNCTION CAUSE IS POWER SUPPLY OR OTHER Remove the starter relay. Measure the voltage of the connector terminal (primary coil power supply) on the starter relay wiring harness while cranking. Is the voltage B+ ?	Yes	Go to Step 12.
9		No	Go to the next step.
10	INSPECT STARTER RELAY PRIMARY COIL POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT Switch the ignition to off. Disconnect the keyless control module connector. Verify continuity between keyless control module terminal 4B and starter relay terminal (primary coil power supply). Is there continuity?	Yes	Go to the next step.
10		No	Repair or replace suspect wiring harness and connector.
11	INSPECT STARTER RELAY PRIMARY COIL POWER SUPPLY CIRCUIT FOR SHORT TO GROUND Verify continuity between keyless control module terminal 4B and body ground. Is there continuity?	Yes	Replace the keyless control module. (See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] .)
11		No	Repair or replace suspect wiring harness and connector.
12	DETERMINE IF MALFUNCTION CAUSE IS STARTER RELAY NO.2 OR OTHER Install the starter relay. Remove the starter relay No.2. Short the terminals of the starter relay No.2 terminal C and D on the wiring harness using a jumper wire. Switch the ignition to start. Does the engine start?	Yes	Inspect the following: Starter relay No.2 (See RELAY INSPECTION .) Wiring harness between TCM terminal A5 and starter relay No.2 Wiring harness between BCM terminal 2G and starter relay No.2 Repair or replace the malfunctioning part according to the inspection results.
12		No	Install the starter relay No.2. Go to the next step.
13	DETERMINE IF MALFUNCTION CAUSE IS STARTER RELAY CONTROL CIRCUIT OR OTHER Is the starter relay operation sound heard when the engine starting procedure is performed in Step 12?	Yes	Go to the next step.
13		No	Go to Step 17.
14	INSPECT STARTER MONITOR SIGNAL CIRCUIT Switch the ignition to ON (Engine off). Measure the voltage at keyless control module terminal 4AA. Is the voltage specified? Specification Shift position is not P or N position: 1.0 V or less Shift position is P or N position: 4.0 V or more	Yes	Go to the next step.
14		No	Repair or replace suspect wiring harness and connector.
15	INSPECT STARTER RELAY NO.2 CONTROL CIRCUIT (BETWEEN KEYLESS CONTROL MODULE AND STARTER RELAY NO.2) FOR OPEN CIRCUIT Switch the ignition to off. Disconnect the keyless control module and starter relay No.2 connectors. Verify continuity between keyless control module terminal 4K and starter relay No.2. Is there continuity?	Yes	Go to the next step.
15		No	Repair or replace suspected wiring harness and connector.
16	INSPECT STARTER AND STARTER POWER SUPPLY/GROUND CIRCUIT Inspect the following: Starter Starter and body ground Starter power supply (from battery through starter relay, to starter) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
16		No	Replace the keyless control module. (See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] .)
17	INSPECT STARTER RELAY NO.2 CONTROL CIRCUIT (BETWEEN KEYLESS CONTROL MODULE AND STARTER RELAY NO.2) FOR OPEN CIRCUIT Switch the ignition to off. Disconnect the keyless control module and starter relay No.2 connectors. Verify continuity between the following terminals: Verify continuity between keyless control module terminal 4K and starter relay No.2. Is there continuity?	Yes	Go to the next step.
17		No	Repair or replace suspected wiring harness and connector.
18	INSPECT STARTER RELAY NO.2 CONTROL CIRCUIT (BETWEEN PCM AND STARTER RELAY NO.2) FOR OPEN CIRCUIT Disconnect the PCM connector (with starter relay No.2 connectors left removed). Verify continuity between starter relay No.2 and PCM terminal 1AQ. Is there continuity?	Yes	Go to Step 26.
18		No	Repair or replace suspected wiring harness and connector.
19	DETERMINE IF MALFUNCTION CAUSE IS STARTER CONTROL CIRCUIT OR STARTER Selector lever is in P or N position. Is a clicking sound heard from the starter relay when switch the ignition to start?	Yes	Go to Step 24.
19		No	Go to the next step.
20	DETERMINE IF MALFUNCTION CAUSE IS STARTER RELAY NO.2 OR OTHER Install the starter relay. Remove the starter relay No.2. Short the terminals of the starter relay No.2 terminal C and D on the wiring harness using a jumper wire. Switch the ignition to start. Does the engine start?	Yes	Inspect the following: Starter relay No.2 (See RELAY INSPECTION .) Wiring harness between TCM terminal A5 and starter relay No.2 Wiring harness between BCM terminal 2G and starter relay No.2 Repair or replace the malfunctioning part according to the inspection results.
20		No	Go to the next step.
21	INSPECT STARTER RELAY NO.2 CONTROL CIRCUIT FOR OPEN CIRCUIT Disconnect the PCM connector (with starter relay No.2 connectors left removed). Verify continuity between the following: Starter relay No.2 and PCM 1AQ Starter relay No.2 and starter relay Is there continuity?	Yes	Go to the next step.
21		No	Repair or replace suspected wiring harness and connector. Then repeat Step 19.
22	INSPECT STARTER RELAY AND RELATED CIRCUIT Inspect the following: Starter relay (See RELAY INSPECTION .) Wiring harness between starter relay and ignition switch Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Then repeat Step 19.
22		No	Go to the next step.
23	INSPECT IGNITION SWITCH AND RELATED CIRCUIT Inspect ignition switch and related harnesses. (See IGNITION SWITCH INSPECTION [WITHOUT ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] ) (See PUSH BUTTON START INSPECTION [WITH ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] ) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Then repeat Step 19.
23		No	Go to the next step.
24	INSPECT WIRING HARNESS OF STARTER POWER SUPPLY CIRCUIT Inspect the following harnesses: Between starter relay and battery Between starter relay and starter Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector. Go to the next step.
24		No	Go to the next step.
25	INSPECT STARTER AND GROUND CIRCUIT Inspect the starter. (See STARTER INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
25		No	Go to the next step.
26	DETERMINE IF MALFUNCTION CAUSE IS BASE ENGINE OR OTHER Inspect for seized/hydrolocked engine or drive plate. Is the engine seized or hydrolocked?	Yes	Repair or replace the malfunctioning part according to the inspection results.
26		No	Go to the next step.
27	VERIFY PCM DTC Retrieve any continuous memory DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .) Communication error message is displayed: Inspect the following: Open circuit in wiring harness between main relay terminal C and PCM terminal 1BP or 1BK Open circuit in wiring harness between main relay terminal D and PCM terminal 1AZ Main relay is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminals 1AH or 1AL Open or poor ground circuit (PCM terminal 1B, 1J, 1E) Poor connection of vehicle body ground Repair or replace the malfunctioning part according to the inspection results.
27		No	No DTC is displayed: Go to the next step.
28	VERIFY PRESENT MALFUNCTION DTC Retrieve any KOEO DTCs using M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there DTCs displayed during KOEO inspection?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
28		No	No DTC is displayed: Go to the next step.
29	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The following test should be performed on the advanced keyless entry and push button start system. If not equipped, go to the next step. Start the engine using the mechanical ignition key. Does the engine start?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION 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) Low or dead battery Charging system malfunction Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	VERIFY IF MALFUNCTION CAUSE IS OVERHEATING Is the engine overheating?	Yes	Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .)
3		No	Go to the next step.
4	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Start the engine. Is the starting condition improved?	Yes	Inspect if the purge solenoid valve is stuck open. Repair or replace the malfunctioning part according to the inspection results.
4		No	Go to the next step.
5	INSPECT MAF SENSOR Inspect the MAF sensor for following: Contamination MAF sensor terminal B voltage (ground circuit) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle?	Yes	Inspect the drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	INSPECT PCM FOR POOR GROUND Verify the PCM ground point condition. Is there any ground point looseness or lifting in the PCM?	Yes	Repair the ground point and lifting.
7		No	Go to the next step.
8	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	INSPECT IGNITION SYSTEM RELATED WIRING HARNESS 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 or replace suspect wiring harness and connector.
10	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning part according to the inspection results.
11	VERIFY SPARK PLUG CONDITION Verify the spark plug conditions when the spark plug removed in Step 10. 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. Repair or replace the malfunctioning part according to the inspection results.
11		No	Install the spark plugs on original cylinders. Go to the next step.
12	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
12		No	Go to the next step.
13	INSPECT CMP SENSOR Inspect the CMP sensors. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
13		No	Go to the next step.
14	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
14		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
15	INSPECT FUEL LINE HOLD PRESSURE FOR FUEL LEAKAGE Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
15		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
16	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
16		No	Go to the next step.
17	INSPECT STARTING SYSTEM Inspect the starting system. (See STARTER INSPECTION [MZI 3.7 V6] .) Is the starting system normal?	Yes	Inspect for loose connectors or poor terminal contact. If connectors are normal, inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
17		No	Repair or replace the malfunctioning part according to the inspection results.
18	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION Inspect for 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 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.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .) Communication error message is displayed: Inspect the following: Open circuit in wiring harness between main relay terminal C and PCM terminal 1BP or 1BK Open circuit in wiring harness between main relay terminal D and PCM terminal 1AZ Main relay is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminals 1AH or 1AL Open or poor ground circuit (PCM terminal 1B, 1J, 1E) Poor connection of vehicle body ground Repair or replace the malfunctioning part according to the inspection results.
2		No	No DTC is displayed: Go to the next step.
3	INSPECT APP SENSOR SIGNAL Access the PCM PIDs APP1 and APP2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) 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.
3		No	Inspect for the following: APP sensor (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI 3.7 V6] .) Wiring harnesses and connectors for following: PCM terminal 1Z-APP sensor terminal A PCM terminal 1U-APP sensor terminal B PCM terminal 1AD-APP sensor terminal C PCM terminal 1AB-APP sensor terminal D PCM terminal 1Y-APP sensor terminal E PCM terminal 1X-APP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
4	INSPECT TP SENSOR SIGNAL Access the PCM PIDs TP1 and TP2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Crank the engine with accelerator pedal released. Are the TP1 and TP2 PIDs indicates the closed throttle position?	Yes	Go to the next step.
4		No	Inspect for the following: TP sensor (See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI 3.7 V6] .) Wiring harnesses and connectors for following: PCM terminal 2BO-TP sensor terminal A PCM terminal 2BR-TP sensor terminal B PCM terminal 2AL-TP sensor terminal C PCM terminal 2AP-TP sensor terminal D PCM terminal 2Z-TP sensor terminal E PCM terminal 2AN-TP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
5	DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle?	Yes	Inspect drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	DETERMINE IF MALFUNCTION CAUSE IS CKP SENSOR WIRING HARNESS OR OTHER Access the PCM PID RPM using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Is the RPM PID indicating engine speed during the engine cranking?	Yes	Go to the next step.
7		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 2V Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2R Open or short circuit in CKP sensor wiring harnesses Repair or replace the malfunctioning part according to the inspection results. If the CKP sensor and wiring harness are normal, go to the next step.
8	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	INSPECT IGNITION SYSTEM RELATED WIRING HARNESS 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 or replace suspect wiring harness and connector.
10	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) 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 15.
10		No	Repair or replace the malfunctioning part according to the inspection results.
11	VERIFY SPARK PLUG CONDITION Verify the spark plug conditions when the spark plug removed in Step 10. 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. Repair or replace the malfunctioning part according to the inspection results.
11		No	Install the spark plugs on original cylinders. Go to the next step.
12	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
12		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
13	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
13		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
14	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
14		No	Go to the next step.
15	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER NOTE: The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step. Connect the pressure gauges to A/C low and high pressure side lines. Turn the A/C on and measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?	Yes	Go to the next step.
15		No	If A/C is always on,: Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .) For other symptoms: Inspect the following: Refrigerant charging amount Cooling fan operation Repair or replace the malfunctioning part according to the inspection results.
16	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated?	Yes	Inspect the following: Purge solenoid valve is stuck open. EVAP control system Repair or replace the malfunctioning part according to the inspection results.
16		No	Go to the next step.
17	INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE Is the air leakage felt or heard at intake-air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part according to the inspection results.
17		No	Go to the next step.
18	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the variable valve timing control function properly?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning part according to the inspection results.
19	INSPECT IF MALFUNCTION CAUSE IS LOW ENGINE COMPRESSION OR VALVE TIMING Is the engine compression correct?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
19		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

NOTE
The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step. Connect the pressure gauges to A/C low and high pressure side lines. Turn the A/C on and measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION Inspect for 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 Ignition wiring Electrical connections Fuses Smooth operation of throttle valve Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .) Communication error message is displayed: Inspect the following: Open circuit in wiring harness between main relay terminal C and PCM terminal 1BP or 1BK Open circuit in wiring harness between main relay terminal D and PCM terminal 1AZ Main relay is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminals 1AH or 1AL Open or poor ground circuit (PCM terminal 1B, 1J, 1E) Poor connection of vehicle body ground Repair or replace the malfunctioning part according to the inspection results.
2		No	No DTC is displayed: Go to the next step.
3	INSPECT APP SENSOR SIGNAL Access the PCM PIDs APP1 and APP2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) 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.
3		No	Inspect for the following: APP sensor (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI 3.7 V6] .) Wiring harnesses and connectors for following: PCM terminal 1Z-APP sensor terminal A PCM terminal 1U-APP sensor terminal B PCM terminal 1AD-APP sensor terminal C PCM terminal 1AB-APP sensor terminal D PCM terminal 1Y-APP sensor terminal E PCM terminal 1X-APP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
4	INSPECT TP SENSOR SIGNAL Access the PCM PIDs TP1 and TP2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Crank the engine with accelerator pedal released. Are the TP1 and TP2 PIDs indicates the closed throttle position?	Yes	Go to the next step.
4		No	Inspect for the following: TP sensor (See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI 3.7 V6] .) Wiring harnesses and connectors for following: PCM terminal 2BO-TP sensor terminal A PCM terminal 2BR-TP sensor terminal B PCM terminal 2AL-TP sensor terminal C PCM terminal 2AP-TP sensor terminal D PCM terminal 2Z-TP sensor terminal E PCM terminal 2AN-TP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
5	DETERMINE IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM OR OTHER Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle?	Yes	Inspect drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	DETERMINE IF MALFUNCTION CAUSE IS CKP SENSOR WIRING HARNESS OR OTHER Access the PCM PID RPM using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Is the RPM PID indicating engine speed during the engine cranking?	Yes	Go to the next step.
7		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 2V Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2R Open or short circuit in CKP sensor wiring harnesses Repair or replace the malfunctioning part according to the inspection results. If the CKP sensor and wiring harness are normal, go to the next step.
8	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT IGNITION SYSTEM RELATED WIRING HARNESS 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.
10		No	Repair or replace suspect wiring harness and connector.
11	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning part according to the inspection results.
12	VERIFY SPARK PLUG CONDITION Verify the spark plug conditions when the spark plug removed in Step 11. 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. Repair or replace the malfunctioning part according to the inspection results.
12		No	Install the spark plugs on original cylinders. Go to the next step.
13	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
13		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
14	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
14		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
15	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
15		No	Go to the next step.
16	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the starting condition improved?	Yes	Inspect the following: Purge solenoid valve is stuck open. EVAP control system Repair or replace the malfunctioning part according to the inspection results.
16		No	Go to the next step.
17	INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE Is the air leakage felt or heard at intake-air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part according to the inspection results.
17		No	Go to the next step.
18	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the variable valve timing control function properly?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning part according to the inspection results.
19	INSPECT IF MALFUNCTION CAUSE IS LOW ENGINE COMPRESSION OR VALVE TIMING Is the engine compression correct?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
19		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
1		No	No DTC is displayed: Go to the next step.
2	INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE Inspect for air leakage from the intake-air system components while racing the engine to higher speed. Is there any air leakage detected?	Yes	Repair or replace the malfunctioning part according to the inspection results.
2		No	Go to the next step.
3	VISUALLY INSPECT THROTTLE BODY Is the throttle body free of contamination?	Yes	Go to the next step.
3		No	Clean or replace throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI 3.7 V6] .)
4	INSPECT POWER STEERING OPERATION SIGNAL Access the PCM PID PSP using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Do the PIDs indicate the correct values under trouble condition?	Yes	Go to the next step.
4		No	Inspect the PSP switch and related wiring harnesses. (See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results. If the malfunction is remains, perform the intermittent concern troubleshooting procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [MZI 3.7 V6] .)
5	INSPECT THERMOSTAT Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .) (See THERMOSTAT INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
5		No	Replace the CHT sensor. (See CYLINDER HEAD TEMPERATURE (CHT) SENSOR REMOVAL/INSTALLATION [MZI 3.7 V6] .)
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT IF MALFUNCTION CAUSE IS DRIVE-BY-WIRE CONTROL SYSTEM IDLE LEARNING NOT PERFORMED Warm up the engine. Idle the engine for 5 min. Is the symptom disappeared?	Yes	Symptom troubleshooting completed. (Cause of this symptom is that the idle learning of drive-by-wire control system is not completed.)
1		No	Go to the next step.
2	INSPECT RELATED PART CONDITION 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 Ignition wiring Electrical connections Fuses Smooth operation of throttle valve Vacuum air leakage Air cleaner restriction PCM ground circuit (1B,1E, 1J) Are all items normal?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
3		No	No DTC is displayed: Go to the next step.
4	VERIFY IF MALFUNCTION CAUSE IS OVERHEATING Is the engine overheating?	Yes	Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .)
4		No	Go to the next step.
5	INSPECT MAF SENSOR SIGNAL CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the PCM PID MAF using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Drive the vehicle with monitoring PID. Is the 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. Repair or replace the malfunctioning part according to the inspection results.
6	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER 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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?	Yes	Go to the next step.
6		No	If the A/C is always on: Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .) For other symptoms: Inspect the following: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT POWER STEERING OPERATION SIGNAL Start the engine and idle it. Access the PCM PID PSP using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Does the PID indicate the correct values under trouble condition?	Yes	Go to the next step.
7		No	Inspect the PSP switch operation and wiring harness between PSP switch and PCM terminal 1G. Repair or replace the malfunctioning part according to the inspection results.
8	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
10		No	Go to the next step.
11	INSPECT IGNITION SYSTEM RELATED WIRING HARNESS 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.
11		No	Repair or replace suspect wiring harness and connector.
12	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results.
13	VERIFY SPARK PLUG CONDITION Verify the spark plug conditions when the spark plug removed in Step 12. 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. Repair or replace the malfunctioning part according to the inspection results.
13		No	Install the spark plugs on original cylinders. Go to the next step.
14	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
14		No	Repair or replace the malfunctioning part according to the inspection results.
15	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and run it at idle. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
15		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
16	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
16		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
17	INSPECT LONG TERM FUEL TRIM Start the engine and idle it. Access the PCM PIDs LONG FT1 and LONG FT2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Measure the LONG FT1 PID and LONG FT2 PID at idle. Are PID values normal?	Yes	Go to the next step.
17		No	Less than the specification (too rich): Inspect EVAP control system. Repair or replace the malfunctioning part according to the inspection results. Greater than the specification (too lean): Inspect for air leakage at intake-air system components. Repair or replace the malfunctioning part according to the inspection results. If system is normal, go to the next step.
18	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the starting condition improved?	Yes	Inspect the following: Purge solenoid valve is stuck open. EVAP control system Repair or replace the malfunctioning part according to the inspection results.
18		No	Go to the next step.
19	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the variable valve timing control function properly?	Yes	Go to the next step.
19		No	Repair or replace the malfunctioning part according to the inspection results.
20	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR IMPROPER ENGINE COMPRESSION Is the engine compression correct?	Yes	Inspect the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) If the PCV valve is normal, inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
20		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
21	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the PCM PID MAF using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Drive the vehicle with monitoring PID. Is the MAF PID within specification?

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the PCM PID MAF using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Drive the vehicle with monitoring PID. Is the MAF PID within specification?

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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT COOLING SYSTEM FOR MALFUNCTION Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Start and warm up the engine to normal operating temperature. Is the ECT PID between 82-112 °C {180-233 °F} ?	Yes	Go to the next step.
1		No	ECT PID is higher than 112 °C {233 °F} : Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .) ECT PID is less than 82 °C {180 °F} : Go to the symptom troubleshooting "NO.18 COOLING SYSTEM CONCERNS-RUNS COLD". (See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZI 3.7 V6] .)
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	VERIFY CURRENT INPUT SIGNAL STATUS Access and monitor following PCM and TCM PIDs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) (See ON-BOARD DIAGNOSTIC SYSTEM PID/DATA MONITOR INSPECTION [AY6A-EL] .) PCM PIDs AC_REQ PSP TCM PID TR Are PIDs values normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
3		No	AC_REQ PID is not specified: Inspect the following: A/C switch Evaporator temperature sensor (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [MANUAL AIR CONDITIONER] .) (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Fan switch Communication between climate control unit and instrument cluster (Full-auto air conditioner) Communication between instrument cluster and PCM Short to ground in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) PSP PID is not specified: Inspect the PSP switch. (See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [MZI 3.7 V6] .) TR PID is not specified: Inspect the TR switch. (See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AY6A-EL] .) Repair or replace the malfunctioning part according to the inspection results.
4	INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE Is there air leakage felt or heard at intake-air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part according to the inspection results.
4		No	Inspect the following: Drive-by-wire control system operation APP sensor (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI 3.7 V6] .) Cruise control switch (built-in steering switch) (See CRUISE CONTROL SWITCH INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF MALFUNCTION INCLUDES ROUGH IDLING Does the engine idle roughly?	Yes	Go to the symptom troubleshooting "NO.8 ENGINE RUNS ROUGH/ROLLING IDLE". (See NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI 3.7 V6] .)
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER Turn off the A/C switch and fan switch. Does the A/C magnetic clutch engage?	Yes	Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .)
2		No	Go to the next step.
3	INSPECT INTAKE AIR SYSTEM FOR AIR LEAKAGE 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	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 3.
4	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
4		No	No DTC is displayed: Go to the next step.
5	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Does the engine condition improve?	Yes	Inspect the EVAP control system. Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	VERIFY CURRENT INPUT SIGNAL STATUS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 TP1 TP2 MAF VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
7		No	APP1 or APP2 PID is not specified: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI 3.7 V6] .) TP1 or TP2 PID is not specified: Inspect the TP sensor. (See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI 3.7 V6] .) MAF PID is not specified: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI 3.7 V6] .) VSS PID is not specified: Inspect the VSS. (See VEHICLE SPEED SENSOR (VSS) INSPECTION [AY6A-EL] .) Repair or replace the malfunctioning part according to the inspection results.
8	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PCM and TCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) (See ON-BOARD DIAGNOSTIC SYSTEM PID/DATA MONITOR INSPECTION [AY6A-EL] .) PCM PIDs AC_REQ BOO TCM PID TR Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
8		No	AC_REQ PID is not specified: Inspect the following: A/C switch Evaporator temperature sensor (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [MANUAL AIR CONDITIONER] .) (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Fan switch Communication between climate control unit and instrument cluster (Full-auto air conditioner) Communication between instrument cluster and PCM Short to ground in wiring harness between climate control unit terminal 1L and instrument cluster terminal 1A (Manual air conditioner) BOO PID is not specified: Inspect the brake switch and related wiring harness for vibration or intermittent open/short circuit. (See BRAKE SWITCH INSPECTION .) TR PID is not specified: Inspect the TR switch. (See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AY6A-EL] .) Repair or replace the malfunctioning part according to the inspection results.
9	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 TP1 TP2 MAF VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 TP1 TP2 MAF VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION 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 Ignition wiring Fuel quality (such as proper octane, contamination, winter/summer blend) Electrical connections Smooth operation of throttle valve Engine mount installation Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	VERIFY IF MALFUNCTION CAUSE IS OVERHEATING Is the engine overheating?	Yes	Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .)
3		No	Go to the next step.
4	VISUALLY INSPECT THROTTLE BODY Visually inspect the throttle valve. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI 3.7 V6] .) Are any foreign materials adhere to around throttle valve?	Yes	Clean the throttle valve.
4		No	Go to the next step.
5	VERIFY CURRENT INPUT SIGNAL STATUS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM VPWR MAF TP1 TP2 VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
5		No	APP1 or APP2 PID is not specified: Inspect if output signal from APP sensor changes smoothly. RPM PID is not specified: Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit. VPWR PID is not specified: Inspect for open circuit intermittently. MAF PID is not specified: Inspect for open circuit of the MAF sensor and related wiring harness intermittently. TP1 or TP2 PID is not specified: Inspect if output signal from TP sensor changes smoothly. VSS PID is not specified: Inspect for open circuit of VSS and related wiring harness intermittently. Repair or replace the malfunctioning part according to the inspection results.
6	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	VERIFY SPARK PLUG CONDITION Verify 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. Repair or replace the malfunctioning part according to the inspection results.
7		No	Install the spark plugs on original cylinders. Go to the next step.
8	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
10		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
11	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
11		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
12	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER 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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?	Yes	Go to the next step.
12		No	If the A/C is always on: Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .) For other symptoms: Inspect the following: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
13	INSPECT CRUISE CONTROL SYSTEM NOTE: The following test should be performed for symptom with cruise control ON. If other symptoms exist, go to the next step. Inspect the cruise control system operation. Is the cruise control system normal?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results.
14	INSPECT CURRENT A/F SENSOR SIGNAL Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Inspect the A/F sensor installation and exhaust gas leakage. Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI 3.7 V6] .)
14		No	Go to the next step.
15	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
15		No	Go to the next step.
16	DETERMINE IF MALFUNCTION CAUSE IS CHECK VALVE (TWO-WAY) OR OTHER 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 [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
16		No	Go to the next step.
17	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect the following: Purge solenoid valve is stuck open. EVAP control system Repair or replace the malfunctioning part according to the inspection results.
17		No	Go to the next step.
18	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
18		No	Go to the next step.
19	INSPECT IF MALFUNCTION CAUSE IS LOW ENGINE COMPRESSION OR OTHER Is the engine compression correct?	Yes	Inspect the following: Valve timing Internal transaxle part Engine mounts Check valve (two-way) Repair or replace the malfunctioning part according to the inspection results.
19		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM VPWR MAF TP1 TP2 VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM VPWR MAF TP1 TP2 VSS Monitor each PID while driving the vehicle. Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)

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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?

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

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION 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 Fuel quality (such as proper octane, contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	VERIFY IF MALFUNCTION CAUSE IS OVERHEATING Is the engine overheating?	Yes	Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .)
3		No	Go to the next step.
4	VERIFY CURRENT INPUT SIGNAL STATUS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM MAF TP1 TP2 IAT VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
4		No	APP1 or APP2 PID is not specified: Inspect if output signal from APP sensor changes smoothly. RPM PID is not specified: Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit. MAF PID is not specified: Inspect for intermittent open circuit of MAF sensor and related wiring harness. TP1 or TP2 PID is not specified: Inspect if output signal from TP sensor changes smoothly. IAT PID is not specified: Inspect for air suction in intake-air system. If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses. VSS PID is not specified: Inspect for open circuit of VSS and related wiring harness intermittently. Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	VISUALLY INSPECT THROTTLE BODY Visually inspect the throttle valve. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI 3.7 V6] .) Are any foreign materials adhere to around throttle valve?	Yes	Clean the throttle valve.
8		No	Go to the next step.
9	VERIFY SPARK PLUG CONDITION Verify 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. Repair or replace the malfunctioning part according to the inspection results.
9		No	Install the spark plugs on original cylinders. Go to the next step.
10	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
10		No	Go to the next step.
11	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
12	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER 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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?	Yes	Go to the next step.
12		No	If the A/C is always on: Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .) For other symptoms: Inspect the following: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
13	INSPECT A/C CUT-OFF CONTROL SYSTEM OPERATION Inspect for A/C cut-off operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the A/C cut-off function properly?	Yes	Go to the next step.
13		No	Inspect the A/C cut-off system components. Repair or replace the malfunctioning part according to the inspection results.
14	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
14		No	Go to the next step.
15	DETERMINE IF MALFUNCTION CAUSE IS EVAP CONTROL SYSTEM OR OTHER CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect the following: Purge solenoid valve is stuck open. EVAP control system Repair or replace the malfunctioning part according to the inspection results.
15		No	Go to the next step.
16	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Inspect the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
16		No	Repair or replace the malfunctioning part according to the inspection results.
17	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR OTHER Is the engine compression correct?	Yes	Inspect the following: Valve timing Internal transaxle components Brake system for dragging Repair or replace the malfunctioning part according to the inspection results.
17		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
18	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM MAF TP1 TP2 IAT VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 RPM MAF TP1 TP2 IAT VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

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 the pressure gauge to A/C low and high pressure side lines. Start the engine and idle it. Turn the A/C switch on. Measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK .) Are pressures within specifications?

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT COOLING SYSTEM FOR MALFUNCTION Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Verify the ECT PID is less than 116 °C {241 °F} during driving. Is the ECT PID less than specification?	Yes	Go to the next step.
1		No	Inspect the CHT sensor. (See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6] .) If the CHT sensor is normal, inspect the cooling system for cause of overheating. Repair or replace the malfunctioning part according to the inspection results.
2	INSPECT IAT SENSOR AND MAF SENSOR SIGNALS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) IAT MAF Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
2		No	IAT PID is not specified: Inspect the IAT sensor. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [MZI 3.7 V6] .) MAF PID is not specified: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
3	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
3		No	No DTC is displayed: Go to the next step.
4	INSPECT ENGINE COMPRESSION Is the engine compression correct?	Yes	Go to the next step.
4		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT CKP SENSOR Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
7		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8	INSPECT KS Inspect the KS. (See KNOCK SENSOR (KS) INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the KS. (See KNOCK SENSOR (KS) REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8		No	Go to the next step.
9	INSPECT IGNITION TIMING Inspect the ignition timing. (See ENGINE TUNE-UP [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Replace the fuel.
10	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) IAT MAF Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) IAT MAF Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION Inspect for the following: Air cleaner element for contamination ATF level Fuel quality Coolant level Brake dragging Low tire pressure Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	INSPECT COOLING SYSTEM FOR MALFUNCTION Is any cooling system concern (overheating, runs cold) present?	Yes	Go to the symptom troubleshooting "NO.17 COOLING SYSTEM CONCERNS-OVERHEATING" and "NO.18 COOLING SYSTEM CONCERNS-RUNS COLD". (See NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI 3.7 V6] .) (See NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZI 3.7 V6] .)
3		No	Go to the next step.
4	INSPECT COOLING FAN CONTROL SYSTEM OPERATION Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the cooling fan control system operate properly?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT COOLING SYSTEM FOR MALFUNCTION CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Drive the vehicle while monitoring PID. Is the PID within specification?	Yes	Go to the next step.
5		No	Inspect for following: Coolant leakage Cooling fans operation Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
6	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
7		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8	INSPECT VARIABLE VALVE TIMING CONTROL SYSTEM OPERATION Inspect the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT MAF SENSOR FOR CONTAMINATION Inspect the MAF sensor for contamination. Is there any contamination?	Yes	Replace the MAF sensor. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI 3.7 V6] .)
10		No	Go to the next step.
11	INSPECT ENGINE COMPRESSION Is the engine compression correct?	Yes	Go to the next step.
11		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
12	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
12		No	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
13	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Drive the vehicle while monitoring PID. Is the PID within specification?

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION 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	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	VERIFY IF MALFUNCTION INCLUDES DRIVEABILITY Is any other driveability concern present?	Yes	Go to the appropriate symptom troubleshooting.
3		No	Go to the next step.
4	INSPECT COOLING SYSTEM FOR MALFUNCTION CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Warm up the engine and idle it. Is the PID within specification?	Yes	Go to the next step.
4		No	Inspect for following: Coolant leakage Cooling fans operation Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT FUEL CAP Inspect the fuel-filler cap. (See FUEL-FILLER CAP INSPECTION [MZI 3.7 V6] .) Is there any leakage at fuel-filler cap?	Yes	Replace the fuel-filler cap.
5		No	Go to the next step.
6	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
7		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8	INSPECT CURRENT A/F SENSOR SIGNAL Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Inspect the following: A/F sensor installation Exhaust gas leakage Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8		No	Go to the next step.
9	INSPECT DEFORMED IN EXHAUST SYSTEM Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT PCV VALVE NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
10		No	Go to the next step.
11	INSPECT ENGINE COMPRESSION Is the engine compression correct?	Yes	Go to the next step.
11		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
12	DETERMINE IF MALFUNCTION CAUSE IS CHARCOAL CANISTER OR FUEL TANK VENT SYSTEM Inspect for fuel saturation inside charcoal canister. Is excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister. (See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
12		No	Inspect the fuel tank vent system. (See FUEL TANK INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
13	INSPECT IF MALFUNCTION CAUSE IS THREE-WAY CATALYTIC CONVERTER OR VALVE TIMING Inspect the three-way catalytic converter. (See EXHAUST SYSTEM INSPECTION [MZI 3.7 V6] .) Is the three-way catalytic converter normal?	Yes	Inspect the valve timing. If the valve timing is not normal: Repair or replace the malfunctioning part according to the inspection results. If the valve timing is normal: Inspect the following engine internal part, such as excessive carbon is built-up in combustion chamber. Repair or replace the malfunctioning part according to the inspection results.
13		No	Replace the three-way catalytic converter.
14	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Warm up the engine and idle it. Is the PID within specification?

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION Inspect for the following: External leakage Proper dipstick Proper engine oil viscosity Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR OTHER NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
2		No	Inspect the internal engine parts such as valves, valve guides, valve stem seals, cylinder head drain passage, and piston rings. Repair or replace the malfunctioning part according to the inspection results.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle.

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION 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	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Go to the next step.
3	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER Start the engine and idle it. Turn the A/C switch on and set blower fan to any speed by switching the control panel. Does the A/C compressor engage according to control panel switching?	Yes	Go to Step 5.
3		No	If the A/C compressor is not engaged always: Go to the symptom troubleshooting "NO.23 A/C DOES NOT WORK SUFFICIENTLY". (See NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZI 3.7 V6] .) If the A/C compressor is engaged always: Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .)
4	INSPECT COOLING FAN CONTROL SYSTEM OPERATION Inspect the cooling fan control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the cooling fan control system function properly?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT COOLANT LEAKAGE AT CLIMATE CONTROL UNIT Is there leakage around the climate control unit in passenger compartment?	Yes	Inspect and service heater for leakage.
5		No	Go to the next step.
6	INSPECT COOLANT LEAKAGE AT COOLING SYSTEM PART Is there leakage at the coolant hoses and/or radiator?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	INSPECT ECT SENSOR SIGNAL Access and monitor PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Compare the ECT PID and water temperature gauge on instrument cluster reading. Is the ECT PID reading is same as water temperature gauge reading?	Yes	Go to the next step.
7		No	Inspect the water temperature gauge. (See INSTRUMENT CLUSTER INSPECTION .) If the water temperature gauge is normal, inspect the CHT sensor. (See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
8	INSPECT IF MALFUNCTION CAUSE IS THERMOSTAT OR CYLINDER BLOCK Cool down the engine. Remove the thermostat and inspect the operation. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .) (See THERMOSTAT INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Engine coolant temperature and thermostat are normal, inspect the engine block for leakage or blockage. Repair or replace the malfunctioning part according to the inspection results.
8		No	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
9	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	DETERMINE IF MALFUNCTION CAUSE IS HVAC SYSTEM OR ENGINE Is customer complaint "Lack of passenger compartment heat" only?	Yes	Inspect the A/C and heater system. Repair or replace the malfunctioning part according to the inspection results.
1		No	Go to the next step.
2	VERIFY IDLE SPEED Does the engine speed continue at fast idle?	Yes	Go to the symptom troubleshooting "NO.9 FAST IDLE/RUNS ON". (See NO.9 FAST IDLE/RUNS ON [MZI 3.7 V6] .)
2		No	Go to the next step.
3	INSPECT COOLING FAN CONTROL SYSTEM OPERATION Inspect the cooling fan control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Does the cooling fan control system function properly?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning part according to the inspection results.
4	INSPECT THERMOSTAT Remove the thermostat and inspect the operation. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .) (See THERMOSTAT INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Inspect the water temperature gauge. (See INSTRUMENT CLUSTER INSPECTION .) If the water temperature gauge is normal, inspect the CHT sensor. (See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
4		No	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY EXHAUST GAS COLOR 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	INSPECT IF MALFUNCTION CAUSE IS PCV VALVE OR OTHER NOTE: The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
2		No	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.
3	INSPECT COOLING SYSTEM FOR LEAKAGE WARNING: Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator are hot. Scalding engine coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system. Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes. When you are sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it. 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		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
4	INSPECT INTAKE AIR SYSTEM 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	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 4.
5	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
5		No	No DTC is displayed: Go to the next step.
6	VERIFY CURRENT INPUT SIGNAL STATUS CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 ECT IAT MAF MAP O2S11 O2S21 O2S12 O2S22 TP1 TP2 VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
6		No	APP1 or APP2 PID is not specified: Inspect if output signal from APP sensor changes smoothly. ECT PID is not specified: Inspect intermittent short circuit of CHT sensor and related wiring harnesses. IAT PID is not specified: Inspect for air suction in intake-air system. If normal, inspect intermittent short circuit of IAT sensor and related wiring harnesses. MAF PID is not specified: Inspect for intermittent open circuit of MAF sensor and related wiring harness. MAP PID is not specified: Inspect for intermittent open circuit of MAP sensor and related wiring harness. O2S11 or O2S21 PID is not specified: Inspect for intermittent open circuit of suspect A/F sensor and related wiring harness. O2S12 or O2S22 PID is not specified: Inspect for intermittent open circuit of suspect HO2S and related wiring harness. TP1 or TP2 PID is not specified: Inspect if output signal from TP sensor changes smoothly. VSS PID is not specified: Inspect for open circuit of VSS and related wiring harness intermittently. Repair or replace the malfunctioning part according to the inspection results.
7	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
7		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
8	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT CMP SENSOR Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI 3.7 V6] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	INSPECT ENGINE COMPRESSION Is the engine compression correct?	Yes	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
10		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
11	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

NOTE
The PCV valve cannot be reassembled once it is removed because the tabs will have been broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI 3.7 V6] .) Is there any malfunction?

WARNING
Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator are hot. Scalding engine coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system. Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes. When you are sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it. Does the cooling system hold pressure?

WARNING

Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator are hot. Scalding engine coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system. Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes. When you are sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it. Does the cooling system hold pressure?

CAUTION
While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 ECT IAT MAF MAP O2S11 O2S21 O2S12 O2S22 TP1 TP2 VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

CAUTION

While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) APP1 APP2 ECT IAT MAF MAP O2S11 O2S21 O2S12 O2S22 TP1 TP2 VSS Do the PIDs indicate the correct values under trouble condition? (See PCM INSPECTION [MZI 3.7 V6] .)

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
1		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
2	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Is the fuel line pressure held after ignition is switched to off? (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
2		No	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI 3.7 V6] .) If the fuel injector is normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
3	INSPECT FUEL TANK VENT SYSTEM Inspect for the following: Blockage/restriction or open circuit in wiring harness between engine vacuum port and charcoal canister Blockage in fuel tank vent system Is there any malfunction?	Yes	Replace the vacuum hose.
3		No	Go to the next step.
4	INSPECT PURGE SOLENOID VALVE Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION [MZI 3.7 V6] .) Is the solenoid operating properly?	Yes	Go to the next step.
4		No	Replace the purge solenoid valve. (See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [MZI 3.7 V6] .)
5	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
5		No	No DTC is displayed: Inspect the charcoal canister for fuel saturation. If excess amount of liquid fuel is present, replace the charcoal canister. (See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF THERE IS SQUEAL, CLICK, OR CHIRP SOUND Is a squealing, click or chirping sound present?	Yes	Inspect for the followings: Engine oil level Drive belt tension Purge solenoid valve installation Auto tensioner bearing damaged Splash shield or under cover looseness Generator installation (alignment) Repair or replace the malfunctioning part according to the inspection results.
1		No	Go to the next step.
2	VERIFY IF THERE IS RUMBLE OR GRIND SOUND Is a rumbling or grinding noise present?	Yes	Inspect for the followings: Drive belt tension P/S fluid level Repair or replace the malfunctioning part according to the inspection results.
2		No	Go to the next step.
3	VERIFY IF THERE IS RUMBLE OR GRIND SOUND Is a rattling noise present?	Yes	Inspect rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
3		No	Go to the next step.
4	VERIFY IF THERE IS HISS SOUND Is a hissing noise present?	Yes	Inspect for the following: Vacuum leakage Spark plug looseness Intake-air system leakage Repair or replace the malfunctioning part according to the inspection results.
4	VERIFY IF THERE IS HISS SOUND Is a hissing noise present?	No	Go to the next step.
5	VERIFY IF THERE IS RAP OR ROAR SOUND Is a rapping or roar noise present?	Yes	Inspect looseness for followings: Dynamic dumper Intake-air system Exhaust system Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	VERIFY IF THERE IS KNOCK SOUND Is a knocking noise present?	Yes	Go to the symptom troubleshooting "NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI 3.7 V6] .)
6	VERIFY IF THERE IS KNOCK SOUND Is a knocking noise present?	No	Inspect for followings: Valve clearance (See VALVE CLEARANCE INSPECTION/ADJUSTMENT [MZI 3.7 V6] .) Variable valve timing actuator Repair or replace the malfunctioning part according to the inspection results. If there are normal, noise comes from the engine internal, inspect for friction gear, timing chain or tappet noise.
7	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PART INSTALLATION CONDITION 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 ATX Driveline Suspension Repair or replace the malfunctioning part according to the inspection results.
1		No	Readjust or retighten the 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 SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM AND CLIMATE CONTROL UNIT DTC Switch the ignition to ON (Engine off). Retrieve the PCM and EATC DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) (See DTC DISPLAY .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .) (See DTC TABLE.)
1		No	No DTC is displayed: Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH OR OTHER Disconnect the magnetic clutch connector. Start the engine and turn A/C switch on by switching the control panel. Measure the voltage between magnetic clutch terminal A (wiring harness-side) and body ground. Is the voltage specified? Specification 10.5 V or more	Yes	Go to Step 6.
2		No	Go to the next step.
3	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNET CLUTCH DRIVE SIGNAL Access and monitor the PCM PID ACCS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Start the engine and idle it. Monitor the PID ACCS while turning on and off the air conditioner by switching the control panel. Does the PID change according to air control panel switching? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
3		No	Go to Step 7.
4	INSPECT A/C RELAY Inspect the A/C relay. (See RELAY INSPECTION .) Is the A/C relay normal?	Yes	Go to the next step.
4		No	Replace the A/C relay.
5	DETERMINE IF MALFUNCTION CAUSE IS A/C RELAY CONTROL CIRCUIT OR OTHER Switch the ignition to off. Disconnect the A/C relay and PCM connectors. Verify continuity between A/C relay and PCM terminal 1W (wiring harness-side). Is there continuity?	Yes	Inspect for open circuit in followings: Between ignition switch (1) /IG2 (2) and A/C relay Between battery positive terminal and A/C relay Between A/C relay and magnetic clutch Repair or replace suspect wiring harness and connector.
5		No	Repair or replace suspect wiring harness and connector.
6	INSPECT MAGNETIC CLUTCH GROUND CIRCUIT Verify continuity between magnetic clutch terminal A (wiring harness-side) and body ground. Is there any continuity?	Yes	Replace the A/C compressor. (Magnetic clutch open) (See A/C COMPRESSOR REMOVAL/INSTALLATION .)
6		No	Repair or replace suspect wiring harness and/or poor contact at ground points.
7	DETERMINE IF MALFUNCTION CAUSE IS REFRIGERANT PRESSURE SENSOR OR OTHER Access the PCM PID ACP_PRESS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Monitor the PID ACP_PRESS while turning on and off the air conditioner by switching the control panel. Is the PID value normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Full-auto air conditioner: Go to Step 9. Manual air conditioner: Go to Step 10.
7		No	Go to the next step.
8	INSPECT REFRIGERANT PRESSURE SENSOR Inspect the refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR INSPECTION [MANUAL AIR CONDITIONER] .) (See REFRIGERANT PRESSURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Is the refrigerant pressure sensor normal?	Yes	Inspect for following: Refrigerant charging amount Magnetic clutch seizure Repair or replace the malfunctioning part according to the inspection results.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	DETERMINE IF MALFUNCTION CAUSE IS EVAPORATOR TEMPERATURE SENSOR OR OTHER Access and monitor the EATC PID EVAP_TEMP using the M-MDS. (See PID/DATA MONITOR DISPLAY .) Is the PID EVAP_TEMP value normal? (See PID/DATA MONITOR TABLE .)	Yes	Go to Step 12.
9		No	Go to Step 11.
10	DETERMINE IF MALFUNCTION CAUSE IS EVAPORATOR TEMPERATURE SENSOR OR OTHER (MANUAL AIR CONDITIONER) Remove the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .) Reconnect the climate control unit connector. Measure the voltage at the climate control unit terminal 1P. Is the voltage within the specified? (See CLIMATE CONTROL UNIT INSPECTION [MANUAL AIR CONDITIONER] .)	Yes	Go to Step 14.
10		No	Go to the next step.
11	INSPECT EVAPORATOR TEMPERATURE SENSOR Inspect the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [MANUAL AIR CONDITIONER] .) (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Is the evaporator temperature sensor normal?	Yes	Replace the climate control module. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
11		No	Replace the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .) (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
12	DETERMINE IF MALFUNCTION CAUSE IS INSTRUMENT CLUSTER OR OTHER (FULL-AUTO AIR CONDITIONER) Verify the information display indication of A/C system while turning on and off the air conditioner by switching the control panel. Does the information display indicate properly?	Yes	Replace the instrument cluster. (instrument cluster does not receive the A/C request signal from climate control unit or transmit it to PCM.) (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
12		No	Go to the next step.
13	DETERMINE IF MALFUNCTION CAUSE IS CLIMATE CONTROL UNIT OR OTHER (FULL-AUTO AIR CONDITIONER) Inspect the information display. (See INFORMATION DISPLAY INPUT/OUTPUT CHECK MODE .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
13		No	Replace the climate control unit. (A/C switch malfunction or climate control unit does not determine the A/C request or transmit A/C request signal.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
14	DETERMINE IF MALFUNCTION CAUSE IS INSTRUMENT CLUSTER OR OTHER (MANUAL AIR CONDITIONER) Remove the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .) Reconnect the climate control unit connector. Start the engine and idle it. Measure the voltage at the climate control unit terminal 1L while turning on and off the air conditioner by switching the control panel. Is the voltage change in specified according to air control panel switching? (See CLIMATE CONTROL UNIT INSPECTION [MANUAL AIR CONDITIONER] .) Specification Turn on the A/C: Below 1.0 V Turn off the A/C: Approx. 5.0 V	Yes	Replace the instrument cluster. (Instrument cluster does not receive the A/C request signal from climate control unit or transmit it to PCM.) (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
14		No	Go to the next step.
15	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL RELATED WIRING HARNESS OR CLIMATE CONTROL UNIT (MANUAL AIR CONDITIONER) Inspect for open or short circuit between climate control unit terminal 1L and instrument cluster terminal 1A. Is there any malfunction?	Yes	Repair or replace suspect wiring harness and connector.
15		No	Replace the climate control unit. (A/C switch malfunction or climate control unit does not determine the A/C request or transmit the A/C request signal.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .)
16	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.
(1) without advanced keyless entry and push button start system (2) with advanced keyless entry and push button start system

(1)	Without advanced keyless entry and push button start system

(2)	With advanced keyless entry and push button start system

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM AND CLIMATE CONTROL UNIT DTC Switch the ignition to ON (Engine off). Retrieve PCM and EATC DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) (See DTC DISPLAY .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .) (See DTC TABLE.)
1		No	No DTC is displayed: Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH OR OTHER Start the engine and idle it. Turn the A/C switch on with blower switch is on. Remove the A/C relay. Does the magnetic clutch disengage?	Yes	Go to Step 4.
2		No	Go to the next step.
3	INSPECT IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH POWER SUPPLY OR MAGNETIC CLUTCH Switch the ignition to off. A/C relay is removed. Disconnect the A/C compressor connector. Switch the ignition to ON. Measure the voltage between magnetic clutch terminal A and body ground. Is the voltage B+ ?	Yes	Repair or replace suspect wiring harness and connector.
3		No	Replace the A/C compressor. (Magnetic clutch engagement is stuck.) (See A/C COMPRESSOR REMOVAL/INSTALLATION .)
4	INSPECT A/C RELAY Inspect the A/C relay. (See RELAY INSPECTION .) Is the A/C relay normal?	Yes	Go to the next step.
4		No	Replace the A/C relay.
5	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNETIC CLUTCH CONTROL CIRCUIT Access and monitor the PCM PID ACCS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Start the engine and idle it. Turn the A/C switch on and off with blower switch is on. Is the PID value always ON?	Yes	Replace the climate control module. (A/C switch signal is always on.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
5		No	Inspect for short to ground between PCM terminal 1W and A/C relay. Repair or replace suspect wiring harness and connector.
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY A/C SYSTEM OPERATION Does the magnetic clutch disengage when the A/C switch is turned off?	Yes	Go to the next step.
1		No	Go to the symptom troubleshooting "NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI 3.7 V6] .)
2	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
2		No	No DTC is displayed: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI 3.7 V6] .) Repair or replace the malfunctioning part according to the inspection results.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY IF THERE IS DRIVEABILITY MALFUNCTION OR EXHAUST GAS MALFUNCTION Are any driveability or exhaust smoke concerns present?	Yes	Go to the appropriate symptom troubleshooting.
1		No	Go to the next step.
2	INSPECT RELATED PART CONDITION Inspect the following: Electrical connections Vacuum lines Fuel quality Are all items normal?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
3		No	No DTC is displayed: Go to the next step.
4	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
4		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
5	DETERMINE IF MALFUNCTION CAUSE IS CHARCOAL CANISTER OR FUEL TANK VENT SYSTEM Inspect the charcoal canister for fuel saturation. Is excess amount of liquid fuel present in canister?	Yes	Replace the charcoal canister. (See CHARCOAL CANISTER, CANISTER VENT (CV) SOLENOID VALVE, AIR FILTER COMPONENT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
5		No	Inspect the fuel tank vent system. Repair or replace the malfunctioning part according to the inspection results. If the fuel tank vent system is normal, suggest trying a different brand since sulphur content can vary in different fuels.
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
1		No	No DTC is displayed: Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS NON-RETURN VALVE OR OTHER Make sure the non-return valve is installed properly. Inspect the nonreturn valve operation. (See NON-RETURN VALVE INSPECTION [MZI 3.7 V6] .) Is the nonreturn valve normal?	Yes	Inspect for the following: Improper use of fuel nozzle Inadequate fuel filling speed Repair or replace the malfunctioning part according to the inspection results.
2		No	Nonreturn valve is installed improperly: Reinstall 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 SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC Switch the ignition to ON (Engine off). Retrieve any DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI 3.7 V6] .)
1		No	No DTC is displayed: Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS NONRETURN VALVE OR OTHER Remove the fuel-filler pipe. Make sure the nonreturn valve is installed properly. Inspect the nonreturn valve operation. (See NON-RETURN VALVE INSPECTION [MZI 3.7 V6] .) Is the nonreturn valve normal?	Yes	Inspect for the following: Improper use of fuel nozzle Fuel is not inserted correctly. Fuel shut-off valve Repair or replace the malfunctioning part according to the inspection results.
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 SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY SPARK PLUG CONDITION Remove all spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION [MZI 3.7 V6] .) Inspect the spark plug condition. (See SPARK PLUG INSPECTION [MZI 3.7 V6] .) Is the spark plug condition normal?	Yes	Symptom 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	DETERMINE IF MALFUNCTION CAUSE IS ENGINE OIL LOSS OR OTHER 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 SPARK PLUG 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 [MZI 3.7 V6] .)
4	INSPECT ENGINE COMPRESSION Inspect the compression pressure at suspected malfunctioning cylinder. (See COMPRESSION INSPECTION [MZI 3.7 V6] .) Is the compression pressure correct?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	INSPECT IGNITION SYSTEM OPERATION Install all spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION [MZI 3.7 V6] .) Perform the spark test at suspected malfunctioning cylinder. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible? (Compare with normal cylinder.)	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Inspect the fuel injector for the following: Open or short circuit in injector Leakage Injection volume Repair or replace the malfunctioning part according to the inspection results.
6		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
7	INSPECT SPARK PLUG 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 [MZI 3.7 V6] .)
8	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Do the fuel injectors operate properly?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	INSPECT AIR CLEANER ELEMENT Is the air cleaner element free of clogging?	Yes	Go to the next step.
9		No	Replace the air cleaner element.
10	INSPECT IGNITION SYSTEM OPERATION Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning part according to the inspection results.
11	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
12	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PCM PIDs: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) ECT O2S11 (When engine can be started.) O2S12 (When engine can be started.) O2S21 (When engine can be started.) O2S22 (When engine can be started.) MAF Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results.
13	INSPECT PURGE CONTROL SYSTEM OPERATION Perform the purge control inspection. (When engine can be started.) (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI 3.7 V6] .) Is the purge control correct?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results.
14	INSPECT ENGINE COMPRESSION Perform the compression inspection. (See COMPRESSION INSPECTION [MZI 3.7 V6] .) Is the compression pressure correct?	Yes	Visually inspect for deformed exhaust system part. Repair or replace the malfunctioning part according to the inspection results. If normal, replace the fuel. (Poor quality fuel is used.)
14		No	Repair or replace the malfunctioning part according to the inspection results.
15	INSPECT INTAKE-AIR SYSTEM FOR AIR SUCTION Inspect the following: Intake-air system for air leakage (When the engine cannot be started.) Intake manifold vacuum (When the engine can be started.) Is air sucked in from intake-air system?	Yes	Repair or replace the malfunctioning part according to the inspection results.
15		No	Go to the next step.
16	INSPECT FUEL LINE PRESSURE Install the fuel pressure gauge between the fuel pipe and fuel distributor. Measure the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI 3.7 V6] .) Is the fuel line pressure correct?	Yes	Go to the next step.
16		No	Zero or low: Inspect for the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI 3.7 V6] .)
17	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PCM PIDs: (See ON-BOARD DIAGNOSTIC TEST [MZI 3.7 V6] .) ECT O2S11 (When engine can be started.) O2S12 (When engine can be started.) O2S21 (When engine can be started.) O2S22 (When engine can be started.) MAF Are all PIDs normal? (See PCM INSPECTION [MZI 3.7 V6] .)	Yes	Inspect the PCM ground condition. Repair or replace the malfunctioning part according to the inspection results.
17		No	Repair or replace the malfunctioning part according to the inspection results.
18	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.

Inspection Method for Sensors

Connect the M-MDS to the DLC-2.
Switch the ignition to ON (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 111

Scheme 111: Inspection Method for Actuators or Relays

Connect the M-MDS to the DLC-2.
Switch the ignition to ON (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.

Input Signal System Inspection Procedure

Find an irregular signal. (See «FINDING IRREGULAR SIGNALS»(ref-581681-S28584155142013101400000) .)
Locate source. (See «LOCATING THE SOURCE OF UNUSUAL SIGNALS»(ref-581681-S03402565512013101400000) .)
Repair or replace the malfunctioning part.
Confirm that the irregular signal is no longer detected.

Input signal system inspection for variable resistance type

When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the M-MDS 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 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the wiring harness for open or short circuits. If the sensor and the M-MDS voltages are the same, inspect for the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) If there are no problems, proceed to next investigation below.

Standard power supply system inspection for variable resistance type

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

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 112

Scheme 112: Thermistor type (IAT sensor and CHT sensor)

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 M-MDS 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 M-MDS voltages, inspect the wiring harness for open or short circuits. If the sensor and the M-MDS 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.

Engine coolant temperature compensation inspection

Connect the M-MDS to the DLC-2.
Access the following PCM 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: CHT sensor and related wiring harness (See «CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6]»(ref-581669-S31089791712013101400000) .) Throttle body and related wiring harness (See «THROTTLE BODY INSPECTION [MZI 3.7 V6]»(ref-581679-S20583505902013101400000) .)

Load compensation inspection

Start the engine and idle it.
Connect the M-MDS to the DLC-2.
Verify that P0506:00, P0507:00 is not displayed. If the P0506:00, P0507:00 are displayed, perform the DTC inspection. (See «DTC P0506:00 [MZI 3.7 V6]»(ref-581634-S03616442642013101400000) .) (See «DTC P0507:00 [MZI 3.7 V6]»(ref-581634-S26045540002013101400000) .)
Access the PCM PID RPM. 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. If load condition is not as specified, inspect the following: A/C switch and related wiring harness (See «CLIMATE CONTROL UNIT INSPECTION [MANUAL AIR CONDITIONER]»(ref-581664-S00686458732013101400000) .) (See «CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER]»(ref-581663-S40376799252013101400000) .) Fan switch and related wiring harness (See «CLIMATE CONTROL UNIT INSPECTION [MANUAL AIR CONDITIONER]»(ref-581664-S00686458732013101400000) .) (See «CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER]»(ref-581663-S40376799252013101400000) .)

Throttle position (TP) sweep inspection

Connect the M-MDS to the DLC-2.
Switch the ignition to ON.
Verify that none of the following DTC are displayed: P0122:00, P0123:00, P0222:00, P0223:00, P2101:00, P2107:00, P2111:00, P2112:00, P2122:00, P2123:00, P2127:00, P2128:00, P2135:00, P2138:00 If any one DTC is displayed, perform the DTC inspection. (See «DTC TABLE [MZI 3.7 V6]»(ref-581634-S02418225892013101400000) .)
Access the PCM PIDs TP1, TP2.
Verify that the PID reading is within the CTP value. (See «PCM INSPECTION [MZI 3.7 V6]»(ref-581669-S17071525992013101400000) .) If the PID reading is out of range, perform the following: Remove the air duct from the throttle body. Verify that the throttle valve opens when the accelerator pedal is depressed. If the throttle valve opens, inspect the TP sensor and related wiring harness. (See «THROTTLE POSITION (TP) SENSOR INSPECTION [MZI 3.7 V6]»(ref-581669-S05691484182013101400000) .) If the throttle valve does not open, inspect the throttle valve actuator 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: TP sensor
Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See «PCM INSPECTION [MZI 3.7 V6]»(ref-581669-S17071525992013101400000) .) If the PID reading is out of range, perform the followings: Remove the air duct from throttle body. Verify that the throttle valve opens when throttle pedal is depressed. If the throttle valve opens, inspect the TP sensor and related wiring harness. (See «THROTTLE POSITION (TP) SENSOR INSPECTION [MZI 3.7 V6]»(ref-581669-S05691484182013101400000) .) If the throttle valve does not open, inspect the throttle valve actuator control motor and related wiring harness.

Fuel Cut Control System Inspection

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

If active command mode function of the M-MDS is used

Warm up the engine and idle it.
Connect the M-MDS to the DLC-2.
Select the PCM PIDs RPM and FUELSYS.
Monitor the both PIDs while performing the following steps. Depress the accelerator pedal and increase the RPM PID to 4,000 rpm . Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUELSYS PID is OL, and CL when the RPM PID drops below 1,200 rpm . If not as specified, inspect the following. CHT sensor and related harness (See «CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6]»(ref-581669-S31089791712013101400000) .)

If active command mode function of the M-MDS is not used

Warm up the engine and idle it.
Measure the fuel injector control signal wave profile using the oscilloscope while performing the following steps. Depress the accelerator pedal and increase the engine speed to 4,000 rpm . Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the wave profile constant B+ , and appears wave, when the engine speed drops below 2,200 rpm . If not as specified, inspect the following. CHT sensor and related harness (See «CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI 3.7 V6]»(ref-581669-S31089791712013101400000) .)

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. (See «SPARK PLUG REMOVAL/INSTALLATION [MZI 3.7 V6]»(ref-581671-S01346552472013101400000) .) Ensure that the spark plugs don't have carbon deposits. Are the spark plugs normal? Yes Go to the next step. No Perform 2 times of no-load racing at 4,000 rpm for 2 min to burn off the carbon deposits. Repeat this step. 2 Inspect the spark plugs for damage, wear, and proper plug gap. Are the spark plugs normal? Yes Go to the next step. No Replace the spark plugs, then go to the next step. (See «SPARK PLUG REMOVAL/INSTALLATION [MZI 3.7 V6]»(ref-581671-S01346552472013101400000) .) 3 Reconnect the spark plugs to the ignition coil. Ground the spark plugs to the engine. Is a strong blue spark visible at each cylinder while cranking? Yes Ignition system is normal. No Some cylinders do not spark: Go to the next step. All cylinders do not spark: Go to Step 5. 4 Inspect the following wiring harnesses for open or short: Ignition coil No.1 terminal C-PCM terminal 2BB Ignition coil No.2 terminal C-PCM terminal 2AT Ignition coil No.3 terminal C-PCM terminal 2B Ignition coil No.4 terminal C-PCM terminal 2AX Ignition coil No.5 terminal C-PCM terminal 2C Ignition coil No.6 terminal C-PCM terminal 2D Are the wiring harnesses normal? Yes Inspect the ignition coil. (See «IGNITION COIL INSPECTION [MZI 3.7 V6]»(ref-581671-S04809251692013101400000) .) Repair or replace the malfunctioning part according to the inspection results. No Repair or replace suspect wiring harness and connector, then go to Step 1. 5 Measure the voltage at terminal A in each ignition coils. Is the voltage B+ ? Yes Go to the next step. No Inspect the power supply circuit of ignition coils. Repair or replace suspect wiring harness and connector. 6 Verify the continuity between each ignition coils terminal B and battery negative terminal. Is there continuity? Yes Go to the next step. No Inspect the ground circuit of ignition coils. Repair or replace suspect wiring harness and connector. 7 Does the PCM connector or ignition coil connectors have poor connection? Yes Repair or replace the connector, then go to Step 1. No Go to the next step. 8 Are the CKP sensor and crankshaft pulley normal? Yes Inspect for open or short circuit in wiring harness and connector of CKP sensor. Repair or replace suspect wiring harness and connector. No Repair or replace the malfunctioning part according to the inspection results, then go to Step 1.

A/C Cut-off Control System Inspection

Start the engine.
Turn the A/C switch and the fan switch on.
Verify that the magnetic clutch actuates. If it does not actuate, go to symptom troubleshooting "NO.23 A/C DOES NOT WORK SUFFICIENTLY". (See «NO.23 A/C DOES NOT WORK SUFFICIENTLY [MZI 3.7 V6]»(ref-581681-S17731561122013101400000) .)
Fully open the throttle valve and verify that the magnetic clutch does not actuate for 2-5 s . If it actuates, inspect as follows: A/C relay (See «RELAY INSPECTION»(ref-581640-S26749992412013101400000) .) Open or short to ground circuit in wiring harness and connectors (Ignition switch (without advanced keyless entry and push button start system)/IG2 relay (with advanced keyless entry and push button start system)-A/C relay-PCM terminal 1W) A/C related parts APP1, APP2 PIDs

Cooling Fan Control System Inspection

Connect the M-MDS to the DLC-2.
Start the engine and warm it up to normal operating temperature.
Perform the KOER self test. (See «KOEO/KOER SELF TEST [MZI 3.7 V6]»(ref-581634-S35342123672013101400000) .)
Verify the cooling fan operates during KOER self test.

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 the M-MDS

Note. Use the IDS (laptop PC) because the PDS (Pocket PC) does not support the EVAP system test.

EVAP system test out line

The EVAP system test, which can substituted for the run drive cycle as an EVAP control system repair confirmation method, can detect the small / large leak or blockage without run-drive cycle.

Note. M-MDS can not detect "VERY SMALL LEAK". To identify the leak point, please use the leak tester or ultrasonic leak detector.

EVAP system test description

Scheme 113

Scheme 114

Scheme 115

The EVAP system test finds gas leaks or blockage of EVAP system using the changes of the fuel tank pressure. This test starts after sending an on-demand test signal from the M-MDS to the PCM. This test consists of three stages, and each stage is performed automatically as follows: Stage 1 test (Test for large leak or blockage) M-MDS send the stage 1 test start signal to the PCM. PCM controls the CV solenoid valve and purge solenoid valve to control the tank pressure to the targeted value. M-MDS detect the large leak or the purge line blockage if the tank pressure does not arrive at the target vacuum in specified period. Stage 2 test (Test for small leak) When fuel tank pressure arrived at the targeted pressure at stage 1 test, M-MDS send the stage 2 test signal to the PCM to turn off the purge solenoid to keep the tank pressure. M-MDS detect the small leak if the tank pressure can not keep within the target in specified period. Stage 3 test (Test for blockage) M-MDS send the stage 3 test signal to the PCM to turn off the CV solenoid for check the blockage of EVAP system. M-MDS detect blockage of the CV solenoid valve or air filter if the tank pressure does not arrive at the target (atmosphere).

EVAP system malfunction judgment

Scheme 116

M-MDS detect the small / large leak or blockage based on fuel tank pressure at the end of EVAP Test.

Evaporative system test procedure

Scheme 117

Verify that all PIDs within the following specifications. NOTE: To successfully perform this procedure, all PIDs must be within the specifications before proceeding to the next step.
Select the following items from the initialization screen of the M-MDS. Select the "Powertrain". Select the "Fuel". Select the "EVAP Test". Verify that ECT and IAT are within the specifications at the confirmation screen. To successfully perform this procedure, ECT and IAT must be within the spec before proceeding to the next step. Fuel Level must be maintained within 15 %-85 % . PCM will cancel the EVAP Test If the Fuel Level is lower than 15 % or higher than 85 % .
Verify the test results described on the M-MDS and follow the instructions.

Scheme 118

Scheme 118: EVAP system leak inspection using leak tester

Scheme 119

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 {13.1-15.0 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. NOTE: INSPECT FUEL FILLER CAP AND FILLER NECK Visually inspect for damage, insufficient sealing, rust, cracks or warps for filler cap and filler neck. Repair or replace if necessary. Connect the receiver assembly ( SST : 134-01059) to the vehicle cap test hose assembly (part of the SST ) and the fuel-filler cap from the vehicle. Connect the cap adaptor ( SST : 134-01058) 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 M-MDS to the DLC-2.
Switch the ignition to ON (Engine off).
Request the PCM on-board device control (Mode 08) using the M-MDS to close the canister vent value. NOTE: The canister vent value is closed for 10 min unless the following any actions are done: Engine is started. Ignition is switched to off.
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 EVAP system hoses.
If the gauge and the flow meter do not settle to a measurable level after 2-3 min {0.08-0.11 in} , then refer to the Mazda Workshop Manual to verify that the canister vent valve is properly closed. If canister vent valve is properly closed. The EVAP system has large leakage. Check for leakage and repair as necessary.
Verify the pressure gauge and flow meter reading to determine if there is an EVAP leak: NO EVAPORATIVE LEAK: The flow meter registers "zero flow" and the pressure gauge returns to the pre-set pressure of 356 mm {14.0 in} of water (H2O). EVAPORATIVE LEAK: The pressure does not return to the preset level of 356 mm {14.0 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 Control System [Mzi 3.7 V6]]: Diagnosis Mazda 6 GJ

SYMPTOM DIAGNOSTIC INDEX [MZI 3.7 V6]

Scheme 107

Scheme 108

Scheme 109

Scheme 110

Diagnostic Procedure

Inspection Method for Sensors

Scheme 111

Input Signal System Inspection Procedure

Input signal system inspection for variable resistance type

Standard power supply system inspection for variable resistance type

GND system inspection for variable resistance type

Scheme 112

Input signal system inspection for thermistor type

GND system inspection for thermistor type

Engine coolant temperature compensation inspection

Load compensation inspection

Throttle position (TP) sweep inspection

Fuel Cut Control System Inspection

Spark Test

A/C Cut-off Control System Inspection

Cooling Fan Control System Inspection

Evaporative Emission (EVAP) System Leak Inspection

EVAP system leak inspection using the M-MDS

Scheme 113

Scheme 114

Scheme 115

Scheme 116

Scheme 117

Scheme 118

Scheme 119

More articles — Symptom Troubleshooting [Engine Control System [Mzi 3.7 V6]]

Login / Signup

Enter the code

You have successfully logged in!