Symptom Troubleshooting [Engine Controls MZI-3.7]: Diagnosis — Mazda CX-9 I рестайлинг (2012-2016)

SYMPTOM DIAGNOSTIC INDEX [MZI-3.7]

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

Diagnostic Index

No.	TROUBLESHOOTING ITEM		DESCRIPTION	REFERENCE
1	Melting of main or other fuses			(See NO. 1 MELTING OF MAIN OR OTHER FUSES [MZI-3.7] .)
2	MIL illuminates		The MIL is illuminated incorrectly.	(See NO. 2 MIL ILLUMINATES [MZI-3.7] .)
3	Will not crank		The starter does not work.	(See NO. 3 WILL NOT CRANK [MZI-3.7] .)
4	Hard to start/long crank/erratic start/erratic crank		The starter cranks the engine at normal speed but the engine requires excessive cranking time before starting.	(See NO. 4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK [MZI-3.7] .)
5	Engine stalls.	After start/at idle	The engine stops unexpectedly.	(See NO. 5 ENGINE STALLS-AFTER START/AT IDLE [MZI-3.7] .)
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] .)
7	Slow return to idle		The engine takes more time than normal to return to idle speed.	(See NO. 7 SLOW RETURN TO IDLE [MZI-3.7] .)
8	Engine runs rough/rolling idle		The engine speed fluctuates between the specified idle speed and lower speed and the engine shakes excessively. The idle speed is too slow and engine shakes excessively.	(See NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI-3.7] .)
9	Fast idle/runs on		The engine speed continues at fast idle after warm-up. The engine runs after the ignition switch is turned off position.	(See NO. 9 FAST IDLE/RUNS ON [MZI-3.7] .)
10	Low idle/stalls during deceleration		The engine stops unexpectedly at the beginning of deceleration or recovery from deceleration.	(See NO. 10 LOW IDLE/STALLS DURING DECELERATION [MZI-3.7] .)
11	Engine stalls/quits.	Acceleration/cruise	The engine stops unexpectedly at the beginning of acceleration or during acceleration. The engine stops unexpectedly while cruising.	(See NO. 11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [MZI-3.7] .)
	Engine runs rough.	Acceleration/cruise	The engine speed fluctuates during acceleration or cruising.
	Misses	Acceleration/cruise	The engine misses during acceleration or cruising.
	Buck/jerk	Acceleration/cruise/ deceleration	The vehicle bucks/jerks during acceleration, cruising, or deceleration.
	Hesitation/ stumble	Acceleration	A momentary pause at the beginning of acceleration or during acceleration.
	Surges	Acceleration/cruise	A momentary pause at the beginning of acceleration or during acceleration.
12	Lack/loss of power	Acceleration/cruise	The performance is poor under load (such as power down when climbing hills).	(See NO. 12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [MZI-3.7] .)
13	Knocking/ pinging	Acceleration/cruise	Sound is produced when the air/fuel mixture is ignited by something other than the spark plug (such as hot spot in combustion chamber).	(See NO. 13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI-3.7] .)
14	Poor fuel economy		The fuel economy is unsatisfactory.	(See NO. 14 POOR FUEL ECONOMY [MZI-3.7] .)
15	Emission compliance		Fails emissions test.	(See NO. 15 EMISSION COMPLIANCE [MZI-3.7] .)
16	High oil consumption/leakage		The oil consumption is excessive.	(See NO. 16 HIGH OIL CONSUMPTION/LEAKAGE [MZI-3.7] .)
17	Cooling system concerns	Overheating	The engine runs at higher than normal temperature/overheats.	(See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] .)
18	Cooling system concerns	Runs cold	The engine takes excessive time to reach normal operating temperature.	(See NO. 18 COOLING SYSTEM CONCERNS-RUNS COLD [MZI-3.7] .)
19	Exhaust smoke		Blue, black, or white smoke from exhaust system	(See NO. 19 EXHAUST SMOKE [MZI-3.7] .)
20	Fuel odor (in engine compartment)		Gasoline fuel smell or visible leakage	(See NO. 20 FUEL ODOR (IN ENGINE COMPARTMENT) [MZI-3.7] .)
21	Engine noise		Engine noise from under hood	(See NO. 21 ENGINE NOISE [MZI-3.7] .)
22	Vibration concerns (engine)		Vibration from under hood or driveline	(See NO. 22 VIBRATION CONCERNS (ENGINE) [MZI-3.7] .)
23	A/C does not work sufficiently.		The A/C compressor magnetic clutch does not engage when A/C is turned on.	(See NO. 23 A/C DOES NOT WORK SUFFICIENTLY [MZI-3.7] .)
24	A/C is always on or A/C compressor runs continuously.		The A/C compressor magnetic clutch does not disengage.	(See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .)
25	A/C does not cut off under wide open throttle conditions.		The A/C compressor magnetic clutch does not disengage under wide open throttle.	(See NO. 25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS [MZI-3.7] .)
26	Exhaust sulphur smell		Rotten egg smell (sulphur) from exhaust	(See NO. 26 EXHAUST SULPHUR SMELL [MZI-3.7] .)
27	Fuel refill concerns		The fuel tank does not fill smoothly.	(See NO. 27 FUEL REFILL CONCERNS [MZI-3.7] .)
28	Fuel filling shut off concerns		The fuel does not shut off properly.	(See NO. 28 FUEL FILLING SHUT OFF CONCERNS [MZI-3.7] .)
29	Spark plug condition		An incorrect spark plug condition.	(See NO. 29 SPARK PLUG CONDITION [MZI-3.7] .)
30	ATX concerns	Upshift/downshift engagement	ATX concerns not related to engine performance.	(See SYMPTOM TROUBLESHOOTING ITEM TABLE [AY6A-EL, AY6AX-EL] article.)

DIAGNOSTIC INDEX

Scheme 5

Scheme 5: QUICK DIAGNOSTIC CHART [MZI-3.7]

Scheme 6

Scheme 7

Scheme 8

Diagnostic Procedure

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

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	NOTE: The following test should be performed on the advanced keyless entry system. If not equipped, go to the next step. Start the engine using the mechanical ignition key.Does the engine start?	Yes	Inspect advanced keyless entry system and repair or replace according to inspection result. (See SYMPTOM TROUBLESHOOTING CHART [KEYLESS ENTRY SYSTEM] article.)
1		No	Go to the next step.
2	Do the following conditions appear? The engine is not completely started. PCM DTC P1260 is displayed.	Yes	Both conditions appear: Go to Step 4.
2		No	Either or other condition appears: Go to the next step.
3	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	Does the security light flush?	Yes	Go to the next step.
4	Does the security light flush?	No	Inspect the following: Wiring harnesses and connectors from keyless control module terminal 3W and instrument cluster terminal 1W Wiring harness and connectors from keyless control module terminal 3X and instrument cluster terminal 1X Instrument cluster (See INSTRUMENT CLUSTER INSPECTION article.) Repair or replace the malfunction part according to the inspection results.
5	Retrieve the DTC for immobilizer system. Is there any DTC present? (See DTC INSPECTION [IMMOBILIZER SYSTEM (ADVANCED KEYLESS ENTRY AND START SYSTEM)] article.) (See DTC INSPECTION [IMMOBILIZER SYSTEM (KEYLESS ENTRY SYSTEM)] article.)	Yes	Go to appropriate DTC inspection. (See DTC TABLE [IMMOBILIZER SYSTEM (ADVANCED KEYLESS ENTRY AND START SYSTEM)] article.) (See DTC TABLE [IMMOBILIZER SYSTEM (KEYLESS ENTRY SYSTEM)] article.)
5		No	Go to the next step.
6	Inspect for the following wiring harnesses and connectors: With advanced keyless entry system Between coil terminal A and keyless control module terminal 3V Between coil terminal B and keyless control module terminal 3U Without advanced keyless entry system Between coil terminal A and instrument cluster terminal 1E Between coil terminal B and instrument cluster terminal 1G Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
6		No	Go to the next step, (with advanced keyless entry system) Go to the Step 8. (without advanced keyless entry system)
7	Inspect the following wiring harnesses and connectors for an open or short circuit: Between keyless control module terminal 3W and instrument cluster terminal 1W Between keyless control module terminal 3X and instrument cluster terminal 1X Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
7		No	Go to the next step.
8	Inspect for the following wiring harnesses and connectors: Between PCM terminal 1AL and instrument cluster terminal 1W Between PCM terminal 1AH and instrument cluster terminal 1X Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
8		No	Go to the next step.
9	Inspect the following: Battery connection Battery condition (See BATTERY INSPECTION [MZI-3.7] article) Fuses (See NO. 1 MELTING OF MAIN OR OTHER FUSES [MZI-3.7] ) Transmission in Park or Neutral (AT) Are all items normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part according to inspection results. Repeat Step 9.
10	Turn ignition switch to the ON position. (Engine off) Access PCM PID TR using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Is TR PID indicated P/N when selecting P or N position?	Yes	Go to the next step.
10		No	Inspect TR switch is adjusted properly, inspect for open or short circuit between TR switch and TCM. Repair or replace components as required. Then go to the next step.
11	Is clicking sound heard from starter relay when the ignition switch is turned to START?	Yes	Go to step 14.
11		No	Go to the next step.
12	Inspect the starter relay and following harnesses. Between starter relay and PCM Between starter relay and ignition switch (See: RELAY INSPECTION article) Are they normal?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results. Then go to step 11.
13	Inspect IGNITION switch and related harnesses. (See: IGNITION SWITCH INSPECTION article) Are they normal?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results. Then go to step 11.
14	Inspect the following harnesses: Between starter relay and Battery Between starter relay and Starter Are they normal?	Yes	Go to the next step.
14		No	Repair or replace the malfunctioning part according to the inspection results. Then go to next step.
15	Inspect the starting system. (See: STARTER INSPECTION [MZI-3.7] article) Is starting system normal?	Yes	Go to the next step.
15		No	Repair or replace the malfunctioning part according to the inspection results.
16	Inspect for seized/hydrolocked engine or flywheel. Is ENGINE seized or hydrolocked?	Yes	Repair or replace the malfunctioning part according to the inspection results.
16		No	Go to the next step.
17	Retrieve any PCM continuous memory DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any continuous memory DTCs displayed?	Yes	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay No. 1 and PCM terminal 1BK or 1BP Open circuit in wiring harness between main relay No. 1 and PCM terminal 1AZ Main relay No. 1 is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminals 1AH or 1AL Open or poor GND circuit (PCM terminal 1B, 1E, 1J) Poor connection of vehicle body GND
17		No	No DTC is displayed: Go to the next step.
18	Retrieve any KOEO DTCs using M-MDS. See KOEO/KOER SELF TEST [MZI-3.7] article. Are there DTCs displayed during KOEO inspection?	Yes	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
18		No	No DTC is displayed: Go to the next step.
19	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Vacuum leakage Proper fuel quality (such as proper octane, contamination, winter/summer blend) Loose bands on intake-air system Cracks on intake-air system parts Intake-air system restriction (such as air cleaner element, fresh air duct.) Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Go to the next step.
3	Is engine overheating?	Yes	Go to symptom troubleshooting "No. 17 Cooling system concerns-Overheating". (See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] .)
3	Is engine overheating?	No	Go to the next step.
4	Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Start engine. Is starting condition improved?	Yes	Inspect if the purge solenoid valve is stuck open. Repair or replace the malfunctioning part according to the inspection results.
4		No	Go to the next step.
5	Inspect the MAF sensor for following: Contamination MAF sensor terminal B voltage (GND 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	Attempt to start engine at part throttle. Does engine run smoothly at part throttle?	Yes	Inspect the drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	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.
7		No	Go to the next step.
8	Verify the PCM ground point condition. Is there any ground point looseness or lifting in the PCM?	Yes	Repair the ground point looseness and lifting
8		No	Go to the next step.
9	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
9		No	Repair or replace suspected wiring harness and connector.
10	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
10		No	Repair or replace malfunctioning part to the inspection results.
11	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	Visually inspect the CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] article. Are the CKP sensor normal?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results.
13	Inspect the CMP sensor. (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article.) Is the CMP sensor normal?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results.
14	Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Go to the next step.
14		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
15	Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. Is there any fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
15		No	Go to the next step.
16	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
16		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
17	Inspect the starting system. (See STARTER INSPECTION [MZI-3.7] article.) Is starting system normal?	Yes	Inspect for loose connectors or poor terminal contact.
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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, Replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Verify the following: Vacuum connection Air cleaner element No air leakage from intake-air system No restriction of intake-air system Proper sealing of intake manifold and components attached to intake manifold 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	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay No. 1 and PCM terminal 1BK or 1BP Open circuit in wiring harness between main relay No. 1 and PCM terminal 1AZ Main relay No. 1 is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminals 1AH or 1AL Open or poor GND circuit (PCM terminal 1B, 1E, 1J) Poor connection of vehicle body GND Repair or replace the malfunctioning part according to the inspection results.
2		No	No DTC is displayed: Go to the next step.
3	Access the PCM PIDs APP1 and APP2 using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. 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] article. 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	Access the PCM PIDs TP1, TP2 using the M-MDS. ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Crank the engine with accelerator pedal released. Are the TP1, TP2 PID 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] article. 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	Attempt to start engine at part throttle. Does engine run smoothly at part throttle?	Yes	Inspect the drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	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	Access the PCM PID RPM using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Is RPM PID indicating engine speed during 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 CKP sensor and wiring harness are normal, go to the next step.
8	Inspect CKP sensor. CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] Is the CKP sensor normal?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
9		No	Repair the wiring harnesses and connector.
10	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) 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 the spark plug condition 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 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 spark plugs on original cylinders. Go to the next step.
12	Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Go to the next step.
12		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
13	Visually inspect for fuel leakage at fuel injector, O-ring and fuel line. Is there any fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
13		No	Go to the next step.
14	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
14		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
15	NOTE: The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step. Connect pressure gauges to A/C low and high pressure side lines.Turn A/C on and measure low side and high side pressures.(See REFRIGERANT PRESSURE CHECK article.)Are pressures within specifications?	Yes	Go to the next step.
15		No	If A/C is always on, go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .) For other symptoms: Inspect the following: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
16	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated?	Yes	Inspect the following: Inspect if purge solenoid valve is stuck open. Inspect EVAP control system. Repair or replace the malfunctioning part according to the inspection results.
16		No	Go to the next step.
17	Is air leakage felt or heard at intake-air system components while racing the engine to higher speed?	Yes	Repair or replace the malfunctioning part according to the inspection results.
17		No	Go to the next step.
18	Inspect variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does variable valve timing control function properly?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning parts according to the inspection results.
19	Is the engine compression correct?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
19	Is the engine compression correct?	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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

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

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Verify the following: Vacuum connection External fuel shut off or accessory (such as kill switch, alarm) Fuel quality: proper octane, contamination, winter/summer blend No air leakage from intake-air system Intake-air system restriction (such as air cleaner element, fresh air duct) Proper sealing of intake manifold and components attached to intake manifold 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	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.) Communication error message is displayed: Inspect for the following: Open circuit in wiring harness between main relay and PCM terminal 1BK or 1BP Open circuit in wiring harness between main relay and PCM terminal 1AZ Main relay No. 1 is stuck open. Open or short circuit in wiring harness between the DLC-2 and PCM terminal 1AH or 1AL Open or poor GND circuit (PCM terminal 1B, 1E, 1J) Poor connection of vehicle body GND Repair or replace the malfunctioning part according to the inspection results.
2		No	No DTC is displayed: Go to the next step.
3	Access the PCM PIDs APP1 and APP2 using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. 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 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	Access the PCM PIDs TP1, TP2 using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Crank the engine with accelerator pedal released. Are the TP1, TP2 PID 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] article. 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	Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle?	Yes	Inspect the electronic throttle control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Replace or replace the malfunctioning part according to the inspection results.
5		No	Go to the next step.
6	Visually inspect the exhaust system part. Is there any deformed exhaust system part?	Yes	Replace or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	Access PCM PID RPM using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Is RPM PID indicating the engine speed when cranking the engine?	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 CKP sensor and wiring harness are normal, go to the next step.
8	Visually inspect the CKP sensor. See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CKP sensor normal?	Yes	Go to the next step.
8		No	Replace or replace the malfunctioning part according to the inspection results.
9	Visually inspect the CMP sensor. See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CMP sensor normal?	Yes	Go to the next step.
9		No	Replace or replace the malfunctioning part according to the inspection results.
10	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 suspected wiring harness and connector.
11	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning part according to spark test result.
12	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 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 the fuel line pressure. See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article. Is the fuel line pressure correct?	Yes	Go to the next step.
13		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
14	Visually inspect the fuel leakage at the fuel injector O-ring, and fuel line. Is there any fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
14		No	Go to the next step.
15	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
15		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
16	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated?	Yes	Inspect the following: If the 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	Is air leakage felt or heard at intake-air system components while racing 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 the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does 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	Is the engine compression correct?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
19	Is the engine compression correct?	No	Inspect for causes. 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
1		No	No DTC is displayed: Go to the next step.
2	Is air leakage felt or heard at intake-are system components while racing the engine to higher speed?	Yes	Repair or replace malfunctioning part according to inspection result.
2		No	Go to the next step.
3	Is throttle body free of contamination?	Yes	Go to the next step
3	Is throttle body free of contamination?	No	Clean or replace throttle body. See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI-3.7] article.
4	Access the PCM PID PSP using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Does the PID indicate the correct values according to the steering wheel position?	Yes	Go to the next step
4		No	Inspect the PSP switch and related wiring harness. See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [MZI-3.7] article. Repair or replace the malfunctioning part according to the inspection results. If the malfunction remains, perform the intermittent concern troubleshooting procedure. See INTERMITTENT CONCERN TROUBLESHOOTING [MZI-3.7]
5	Cool down the engine. Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [MZI-3.7] article.) (See THERMOSTAT INSPECTION [MZI-3.7] article.) Is thermostat normal?	Yes	Inspect the CHT sensor. See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI-3.7] article. Repair or replace the malfunctioning part according to the inspection results.
5		No	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZI-3.7] article.)
6	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	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 electronic throttle control system is not completed.)
1		No	Go to the next step.
2	Verify the following: External fuel shut off or accessory (such as kill switch, alarm) Fuel quality (such as proper octane, contamination, winter/summer blend) No air leakage from intake-air system Proper sealing of intake manifold and components attached to intake manifold Ignition wiring Electrical connections Fuses Smooth operation of throttle valve Vacuum air leakage Air cleaner restriction PCM GND 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	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
3		No	No DTC is displayed: Go to the next step.
4	Is the engine overheating?	Yes	Go to symptom troubleshooting "No. 17 Cooling system concerns - Overheating". (See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] .)
4	Is the engine overheating?	No	Go to the next step.
5	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 MAF PID using the M-MDS.See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article.Drive vehicle with monitoring PID. Is MAF PID within specification?	Yes	Go to the next step.
5		No	Inspect for open or short circuit of MAF sensor and related wiring harness. Repair or replace the malfunctioning part according to the inspection results.
6	NOTE: The following test is for stall concerns with A/C on. If other symptoms exist, go to the next step. Connect pressure gauge to A/C low and high pressure side lines.Start engine and idle it.Turn the A/C switch on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK article.)	Yes	Go to the next step.
6		No	If the A/C is always on: Go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously" (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .) For other symptoms: Inspect the following: Refrigerant charging amount Cooling fan operation Repair or replace the malfunctioning part according to the inspection results.
7	NOTE: The following test is for engine running rough with P/S on. If other symptoms exist, go to the next step. Start the engine and idle it.Access PCM PID PSP using the M-MDS.See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article.Is PSP PID within specification?	Yes	Go to the next step.
7		No	Inspect the power steering pressure switch operation and wiring harness between PSP switch and PCM terminal 1G. Repair or replace the malfunctioning part according to the inspection results.
8	Visually inspect the CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] article. Is the CKP sensor normal?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to the inspection results.
9	Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?	Yes	Go to the next step.
9		No	Repair or replace suspected wiring harness and connector
10	Perform the spark test. See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] Is strong blue spark plug visible at each cylinder?	Yes	Go to the next step. If symptoms occurs with A/C on, go to step 15.
10		No	Repair or replace the malfunctioning part according to the inspection results.
11	Verify the spark plug conditions when the spark plug removed in Step 10. Is the spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from injector. Spark plug is grayish white: Inspect the fuel injector for clogging. 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	Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results.
13	Install fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and run it at idle. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is fuel line pressure correct during idle?	Yes	Go to the next step.
13		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
14	Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. Is there any fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
14		No	Go to the next step.
15	Start the engine and idle it. Access PCM PIDs LONG FT1 and LONG FT2 using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Measure LONG FT1 and LONG FT2 at idle. Is PID value normal?	Yes	Go to the next step.
15		No	Less than specification (too rich): Inspect EVAP control system. Greater than 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.
16	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated?	Yes	Inspect the following: If 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	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
17		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
18	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.
18		No	Go to the next step.
19	Inspect the CMP sensor. See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CMP sensor normal?	Yes	Go to the next step.
19		No	Repair or replace the malfunctioning part according to the inspection results.
20	Inspect the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does variable valve timing control system function properly?	Yes	Go to the next step.
20		No	Repair or replace the malfunctioning part according to the inspection results.
21	Is engine compression correct?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
21	Is engine compression correct?	No	Inspect for causes. Repair or replace the malfunctioning part according to the inspection results.
22	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

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

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

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Access the PCM PID ECT using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Start and warm up engine to normal operating temperature. Is 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 symptom troubleshooting "No. 17 Cooling system concerns - Overheating". See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] ECT PID is less than 82°C {180°F}: Go to symptom troubleshooting "No. 18 Cooling system concerns - Runs cold". See NO. 18 COOLING SYSTEM CONCERNS-RUNS COLD [MZI-3.7]
2	Turn the ignition switch to the ON position (Engine off). Retrieve any DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Go to the next step.
3	Access and monitor the following PCM PIDs using the M-MDS: See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. AC_REQ PSP TR Are PIDs values normal? (See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
3		No	If the AC_REQ PID is not normal: Inspect the following: Refrigerant pressure sensor Front climate control unit terminal 2A voltage Wiring harness between front climate control unit terminal 2A and instrument cluster terminal 1C If the TR PID is not normal: Inspect TR switch and related wiring harness for vibration or intermittent open/short circuit. If the PSP PID is not normal: Inspect power steering switch and related wiring harness for vibration or intermittent open/short circuit. Repair or replace the malfunctioning part according to the inspection results.
4	Is there air leakage felt or heard at intake-air system components while racing 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 Accelerator pedal position sensor See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7] article. Cruise control switch (built-in steering switch) See CRUISE CONTROL SWITCH INSPECTION [MZI-3.7] article. 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Does the engine idle roughly?	Yes	Go to symptom troubleshooting "No. 8 Engine runs rough/rolling idle". (See NO. 8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI-3.7] .)
1	Does the engine idle roughly?	No	Go to the next step.
2	Turn off the A/C switch and fan switch. Does the A/C magnetic clutch engage?	Yes	Go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously." (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .)
2		No	Go to the next step.
3	Verify the following: Proper routing of and no damage to vacuum lines No air leakage from intake-air system Are all items normal?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 3.
4	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
4		No	No DTC is displayed: Go to the next step.
5	Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) 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	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. start the engine. Is the engine stall now eliminated?	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	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 and VSS using the M-MDS.See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. APP1 APP2 TP1 TP2 MAF VSS Monitor each PID while driving vehicle.(See PCM INSPECTION [MZI-3.7] article.)Are PIDs normal?	Yes	Go to the next step.
7		No	APP1 or APP2 PID is not normal: Inspect the APP sensor. See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7] article. TP1 or TP2 PID is not normal: Inspect the TP sensor. See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7] article. MAF PID is not normal: Inspect MAF sensor. See MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI-3.7] article. VSS PID is not normal: Inspect the VSS. See VEHICLE SPEED SENSOR (VSS) INSPECTION [AY6A-EL, AY6AX-EL] article. Repair or replace the malfunctioning part according to the inspection results.
8	Access and monitor the following PCM PIDs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. AC_REQ BOO TR Are PIDs values normal? (See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
8		No	AC_REQ PID is not normal: Inspect the followings: Refrigerant pressure sensor Front climate control unit terminal 2A voltage Wiring harness between front climate control unit terminal 2A and instrument cluster terminal 1C BOO PID is not normal: Inspect the brake switch, and related wiring harness for vibration or intermittent open/short circuit. TR PID is not normal: Inspect TR switch and related wiring harness for vibration or intermittent open/short circuit. 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Is the DTC P2299:00 displayed?	Yes	Go to the appropriate DTC inspection. (Drive-by-wire control system operates with brake override system.) See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article, DTC P2299:00.
1		No	Go to the next step.
2	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.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
3		No	No DTC is displayed: Go to the next step.
4	Is engine overheating?	Yes	Go to symptom troubleshooting "No. 17 Cooling system concerns - Overheating". (See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] )
4	Is engine overheating?	No	Go to the next step.
5	Visually inspect the throttle valve. Are any foreign materials adhere to around throttle valve?	Yes	Clean the throttle valve.
5		No	Go to the next step.
6	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 and VSS using M-MDS:See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. APP1 APP2 RPM VPWR TP1 TP2 MAF VSS Monitor each PID while driving the vehicle.Do the PIDs indicate the correct values under trouble condition?(See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
6		No	APP1 or APP2 PID is not normal: Inspect if output signal from APP sensor changes smoothly. RPM PID is not normal: Inspect the CKP sensor and related wiring harness for vibration or intermittent open/short circuit. VPWR PID is not normal: Inspect for open circuit intermittently. TP1 or TP2 PID is not normal: Inspect if output signal from TP sensor changes smoothly. MAF PID is not normal: Inspect for open circuit of the MAF sensor and related wiring harness intermittently. VSS PID is not normal: Inspect for open circuit of VSS and related wiring harness intermittently. Repair or replace the malfunctioning part according to the inspection results.
7	Visually inspect the CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] article. Is the CKP sensor normal?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning part according to the inspection results.
8	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.
8		No	Install the spark plugs on original cylinders. Go to the next step.
9	Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part according to electronic throttle system operation inspection results.
10	Visually inspect deformed 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 the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect the fuel injector. 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
12	Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. Is there any fuel leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
12		No	Go to the next step.
13	NOTE: The following test is for engine stall with the A/C on. If other symptom exists, go to the next step. Connect a pressure gauge to A/C low and high pressure side lines.Turn the A/C on and measure low side and high side pressure.(See REFRIGERANT PRESSURE CHECK article.)Are pressures within specifications?	Yes	Go to the next step.
13		No	If the A/C is always on: Go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .) For other symptoms: Inspect the following: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
14	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 cruise control system normal?	Yes	Go to the next step.
14		No	Repair or replace the malfunctioning part according to the inspection results.
15	Visually inspect the A/F sensor. See ENGINE CONTROLS - CONTROL SYSTEM [MZI-3.7] article, AIR FUEL RATIO (A/F) SENSOR INSPECTION. Is the A/F sensor normal?	Yes	Go to the next step.
15		No	Replace the A/F sensor. See ENGINE CONTROLS - CONTROL SYSTEM [MZI-3.7] article, AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION.
16	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
16		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
17	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] article.) Repair or replace the malfunctioning part according to the inspection results.
17		No	Go to the next step.
18	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Go to the next step.
18		No	Inspect the following: If the purge solenoid valve is stuck open EVAP control system Repair or replace the malfunctioning part according to the inspection results.
19	Visually inspect the CMP sensor. CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CMP sensor normal?	Yes	Go to the next step.
19		No	Repair or replace the malfunctioning part according to the inspection results.
20	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.
20	Is the engine compression correct?	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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

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

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

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Retrieve any PCM DTCs using the M-MDS See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Is the DTC P2299:00 displayed?	Yes	Go to the appropriate DTC inspection. (Drive-by-wire control system operates with brake override system.) See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article, DTC P2299:00.
1		No	Go to the next step.
2	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.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
3		No	No DTC is displayed: Go to the next step.
4	Is the engine overheating?	Yes	Go to symptom troubleshooting "No. 17 Cooling system concerns-Overheating". See NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING [MZI-3.7] .
4	Is the engine overheating?	No	Go to the next step.
5	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 and VSS using the M-MDS:See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. APP1 APP2 RPM TP1 TP2 MAF IAT VSS Monitor each PID while driving the vehicle.Do the PIDs indicate the correct values under trouble condition?(See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
5		No	APP1 or APP2 PID is not normal: Inspect if output signal accelerator pedal position sensor changes smoothly. RPM PID is not normal: Inspect CKP sensor and related wiring harness for vibration or intermittent open/short circuit. TP1, TP2 PID is not normal: Inspect if output signal TP sensor changes smoothly. MAF PID is not normal: Inspect for open circuit of the MAF sensor and related wiring harness intermittently. IAT PID is not normal: 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 normal: Inspect for open circuit of VSS and related wiring harness intermittently. Repair or replace the malfunctioning part according to the inspection results.
6	Visually inspect the CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] article. Is the CKP sensor normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	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	Visually inspect the throttle valve. Are any foreign materials adhere to around throttle valve?	Yes	Clean the throttle valve.
8		No	Go to the next step.
9	Perform the drive-by-wire control system operation inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the drive-by-wire control system function properly?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part according to the inspection results.
10	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 the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
12	NOTE: The following test is for engine stalling with the A/C on concern. If other symptoms exist, go to the next step. Connect pressure gauge to the A/C low and high side pressure lines.Turn the A/C on and measure low side and high side pressures.Are pressures within specifications?(See REFRIGERANT PRESSURE CHECK article.)	Yes	Go to the next step.
12		No	If A/C is always on: Go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously" (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .) For other symptoms: Refrigerant charging amount Condenser fan operation Repair or replace the malfunctioning part according to the inspection results.
13	Inspect for A/C cut-off operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the A/C cut-off function properly?	Yes	Go to the next step.
13		No	Inspect A/C cut-off system components. Repair or replace the malfunctioning part according to the inspection results.
14	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
14		No	Replace PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
15	Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side. Plug opening end of vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect the following: If 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	Visually inspect the CMP sensor. See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CMP sensor normal?	Yes	Go to the next step.
16		No	Repair or replace the malfunctioning part according to the inspection results.
17	Inspect the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
17		No	Repair or replace the malfunctioning part according to the inspection results.
18	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.
18	Is the engine compression correct?	No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
19	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

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

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	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 ECT PID using the M-MDS.See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article.Verify 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 cooling system for cause of overheating. Repair or replace the malfunctioning part according to the inspection results.
2	Access and monitor the following PCM PIDs using the M-MDS: See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. IAT MAF Are all PIDs normal? (See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
2		No	IAT PID is not normal: Inspect IAT sensor See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [MZI-3.7] article. MAF PID is not normal: Inspect MAF sensor See MASS AIR FLOW (MAF) SENSOR INSPECTION [MZI-3.7] article. Repair or replace the malfunctioning part according to the inspection results.
3	Turn the ignition switch to the ON position (engine off). Retrieve the PCM DTC using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
3		No	No DTC is displayed: Go to the next step.
4	Is engine compression correct?	Yes	Go to the next step.
4	Is engine compression correct?	No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
5	Inspect the CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7] article. Is the CKP sensor normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	Inspect the CMP sensor. See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article. Is the CMP sensor normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	Install fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is fuel line pressure correct during idle?	Yes	Go to next step.
7		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
8	Inspect the knock sensor. See KNOCK SENSOR (KS) INSPECTION [MZI-3.7] article. Is the knock sensor normal?	Yes	Go to the next step.
8		No	Replace the knock sensor. See KNOCK SENSOR (KS) REMOVAL/INSTALLATION [MZI-3.7] article.
9	Inspect the ignition timing. See ENGINE TUNE-UP [MZI-3.7] article. Is the ignition timing properly?	Yes	Replace the fuel
9		No	Repair or replace the malfunctioning part according to the inspection results.
10	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Air cleaner element for contamination ATF level Fuel quality Coolant level Brake dragging 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	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Go to the next step.
3	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 ECT using the M-MDS.See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article.Drive vehicle while monitoring the PID.(See PCM INSPECTION [MZI-3.7] article.)Is PID within specification?	Yes	Go to the next step.
3		No	Inspect the following: Coolant leakage Cooling fan and condenser fan operations Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
4	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is fuel line pressure correct during idle?	Yes	Go to the next step.
5		No	Zero or low: Inspect 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
6	Inspect for variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Does the variable valve timing control system function properly?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to the inspection results.
7	Visually inspect the exhaust system part. Is there any deformed exhaust system?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	Inspect for contaminated MAF sensor. Is there any contamination?	Yes	Go to the next step.
8		No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
9	Is engine compression correct?	Yes	Go to the next step.
9	Is engine compression correct?	No	Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
10	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] article.)Is the PCV valve normal?	Yes	Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
10		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
11	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Vacuum lines for leakage or blockage Electrical connections Proper maintenance schedule followed Intake-air system and air cleaner element concerns: obstructions, leakage or dirtiness Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Go to the next step.
3	Is any other driveability concern present?	Yes	Go to appropriate symptom troubleshooting.
3	Is any other driveability concern present?	No	Go to the next step.
4	Access the PCM PID ECT using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Warm up the engine and idle it. Is the ECT PID normal? (See PCM INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
4		No	Inspect for following: Coolant leakage Cooling fan and condenser fan operations Thermostat operation Repair or replace the malfunctioning part according to the inspection results.
5	Inspect fuel-filler cap. (See FUEL-FILLER CAP INSPECTION [MZI-3.7] article.) Is there any leakage at fuel-filler cap?	Yes	Replace the fuel-filler cap.
5		No	Go to the next step.
6	Perform spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning part according to spark test result.
7	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and idle it. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is fuel line pressure correct during idle?	Yes	Go to the next step.
7		No	Zero or low: Inspect 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
8	Inspect the A/F sensor (See ENGINE CONTROLS - CONTROL SYSTEM [MZI-3.7] article, AIR FUEL RATIO A/F SENSOR INSPECTION.) Is the A/F sensor normal?	Yes	Go to the next step.
8		No	Inspect A/F sensor installation and exhaust gas leakage. Repair or replace the malfunctioning part according to spark test result. If normal, replace the A/F sensor. (See ENGINE CONTROLS - CONTROL SYSTEM [MZI-3.7] article, AIR FUEL RATIO A/F SENSOR REMOVAL/INSTALLATION.)
9	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	Is the engine compression correct?	Yes	Repair or replace the malfunctioning part according to the inspection results.
10	Is the engine compression correct?	No	Go to the next step.
11	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
11		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
12	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] article.
12		No	Inspect the fuel tank vent system. (See FUEL TANK INSPECTION [MZI-3.7] article.) Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
13	Inspect the three-way catalytic converter. (See EXHAUST SYSTEM INSPECTION [MZI-3.7] article.) Is the three-way catalytic converter normal?	Yes	Inspect the valve timing. 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. See EXHAUST SYSTEM REMOVAL/INSTALLATION [MZI-3.7] article.
14	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	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] article.)Is the PCV valve normal?	Yes	Go to the next step.
1		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
2	Inspect for the following: External leakage Proper dipstick Proper engine oil viscosity Are all items normal?	Yes	Inspect the internal engine parts such as valves, valve guides, valve stem seals, cylinder head drain passage, and piston rings. Repair or replace the malfunctioning part according to the inspection results.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: Engine coolant level Coolant leakage Water and anti-freeze mixture Radiator condition Collapsed or restricted radiator hoses Radiator pressure cap Overflow system Fan rotational direction Fuses Are all items normal?	Yes	Go to the next step.
1		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Go to the next step.
3	Start the engine and idle it. Turn the A/C switch on and set blower fan to any speed by switching the control panel. Does the A/C compressor engage/disengage according to control panel switching?	Yes	Go to the next step
3		No	If the A/C compressor is not engaged always: Go to the symptom troubleshooting, see NO. 23 A/C DOES NOT WORK SUFFICIENTLY [MZI-3.7] . If the A/C compressor is engaged always: Go to the symptom troubleshooting, see NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .
4	Inspect cooling fan control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) 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 the drive belt. See DRIVE BELT INSPECTION [MZI-3.7] article. Is the drive belt normal	Yes	Go to the next step.
5		No	Replace the drive belt. See DRIVE BELT REMOVAL/INSTALLATION [MZI-3.7] article.
6	Is there leakage around the heater unit in passenger compartment?	Yes	Inspect and service heater for leakage. Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	Is there leakage at the coolant hoses and/or radiator?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7	Is there leakage at the coolant hoses and/or radiator?	No	Go to the next step.
8	Access and monitor the PCM PID ECT using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Compare the ECT PID and water temperature gauge on instrument cluster reading. Is the ECT PID reading the same as water temperature gauge reading?	Yes	Go to the next step
8		No	Inspect the water temperature gauge. See INSTRUMENT CLUSTER INSPECTION article. Repair or replace the malfunctioning part according to the inspection results. If the water temperature gauge reading is normal, inspect the CHT sensor. See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI-3.7] article. Repair or replace the malfunctioning part according to the inspection results.
9	Cool down the engine. Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [MZI-3.7] article.) (See THERMOSTAT INSPECTION [MZI-3.7] article.) Is thermostat normal?	Yes	The engine coolant temperature and thermostat are normal, inspect engine block for leakage or blockage. Repair or replace the malfunctioning part according to the inspection results.
9		No	Replace the thermostat. See THERMOSTAT REMOVAL/INSTALLATION [MZI-3.7] article.
10	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

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

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	What color is smoke coming from the exhaust system?	Blue	Burning oil is indicated. Go to the next step.
		White	Water in combustion is indicated. Go to Step 3.
		Black	Rich fuel mixture is indicated. Go to Step 4.
2	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] article.)Is the PCV valve normal?	Yes	Inspect for the following: Damaged valve guide, stems or valve seals Blocked oil drain passage in cylinder head Piston ring is not seated, seized or worn. Damaged cylinder bore Repair or replace the malfunctioning part according to the inspection results. If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
2		No	Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
3	WARNING: Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator or 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 Repair or replace the malfunctioning part according to the inspection results. 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 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	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
5		No	No DTC is displayed: Go to the next step.
6	WARNING: 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] article. APP1 APP2 ECT IAT MAF MAP O2S11 O2S21 O2S12 O2S22 TP1 TP2 VSS Monitor the PIDs under the black smoke appeared engine condition.Do the PIDs indicate normal according to the engine conditions?See PCM INSPECTION [MZI-3.7] article.	Yes	Go to the next step.
6		No	APP1 or APP2 PID is not normal: Inspect if output signal APP sensor changes smoothly. ECT PID is not normal: Inspect intermittent short circuit of CHT sensor and related wiring harness. IAT PID is not normal: 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 normal Inspect for intermittent open circuit of MAF sensor and related wiring harness. MAP PID is not normal Inspect for intermittent open circuit of MAP sensor and related wiring harness. O2S11 or O2S21 PID is not normal Inspect for intermittent open circuit of suspect A/F sensor and related wiring harness. O2S12 or O2S22 PID is not normal Inspect for intermittent open circuit of suspect HO2S and related wiring harness. TP1 or TP2 PID is not normal Inspect if output signal TP sensor changes smoothly. VSS PID is not normal Inspect for intermittent open circuit of VSS and related wiring harness Repair or replace the malfunctioning part according to the inspection results.
7	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start the engine and run it at idle. Measure fuel line pressure during idle. See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article. Is fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.)	Yes	Go to the next step.
7		No	Zero or low: Inspect 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
8	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is strong blue spark visible at each cylinder?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning part according to spark test result.
9	Inspect the CMP sensor (See CAMSHAFT POSITION (CMP) SENSOR INSPECTION [MZI-3.7] article.) Is the CMP sensor normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning part according to spark test result.
10	Is the engine compression correct?	Yes	Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZI-3.7] article.) Repair or replace the malfunctioning part according to spark test result.
10	Is the engine compression correct?	No	Inspect for cause Repair or replace the malfunctioning part according to spark test result.
11	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

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.

WARNING
Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator or 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.

WARNING

Never remove the cooling system cap or loosen the radiator drain plug while the engine is running, or when the engine and radiator or 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.

WARNING
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.

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Visually inspect for fuel leakage at fuel injector O-ring and fuel line. Service if necessary. Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start engine and idle it. Measure fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is fuel line pressure correct during idle?	Yes	Go to the next step.
1		No	Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
2	Inspect for the following: Blockage/restriction or open circuit in wiring harness between the engine vacuum port and the charcoal canister Blockage in fuel tank vent system Is there any malfunction?	Yes	Replace vacuum hose.
2		No	Go to the next step.
3	Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION [MZI-3.7] article.) Is the solenoid operating properly?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning part according to the inspection results. (See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [MZI-3.7] article.)
4	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
4		No	No DTC is displayed: Inspect 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] article.
5	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect for the followings: Engine oil level Drive belt tension Purge solenoid valve isolation 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	Is a squealing, click or chirping sound present?	No	Go to the next step.
2	Is a rumbling or grinding noise present?	Yes	Inspect for the followings: Drive belt tension P/S fluid level Repair or replace the malfunctioning part according to the inspection results.
2	Is a rumbling or grinding noise present?	No	Go to the next step.
3	Is a rattling noise present?	Yes	Inspect rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
3	Is a rattling noise present?	No	Go to the next step.
4	Is a hissing noise present?	Yes	Inspect for the following: Vacuum leakage Spark plug looseness Intake-air system leakage Repair or replace the malfunctioning part according to the inspection results.
4	Is a hissing noise present?	No	Go to the next step.
5	Is a rapping or roar noise present?	Yes	Inspect looseness for followings: Dynamic dumper Intake-air system Exhaust system Repair or replace the malfunctioning part according to the inspection results.
5	Is a rapping or roar noise present?	No	Go to the next step.
6	Is a knocking noise present?	Yes	Go to symptom troubleshooting "No. 13 Knocking/pinging". (See NO. 13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI-3.7] .)
6	Is a knocking noise present?	No	Inspect for followings: Valve clearance See VALVE CLEARANCE INSPECTION/ADJUSTMENT [MZI-3.7] article. 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following components for loose attaching bolts or worn parts: Cooling fan Drive belt and pulleys Generator Engine mounts Exhaust system mounts Are 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 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Retrieve the PCM and climate control unit DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. See DTC INSPECTION [BCM] article. Are there any DTCs displayed?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.) (See DTC INSPECTION [BCM] article.)
1		No	Go to the next step.
2	Access the PCM PID ACCS using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Start the engine and idle it. Turn the PCM PID ACCS to ON from OFF using the M-MDS simulation function. Is the magnetic clutch engaged?	Yes	Go to the next step.
2		No	Go to Step 9.
3	Measure the voltage at the PCM terminal 1M (wiring harness-side). Is the voltage normal? See PCM INSPECTION [MZI-3.7] article.	Yes	Go to Step 5.
3		No	Go to the next step.
4	Inspect the refrigerant pressure sensor. See REFRIGERANT PRESSURE SWITCH INSPECTION article. Is there any malfunction?	Yes	Replace the refrigerant pressure sensor. See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION article.
4		No	Inspect the following: Refrigerant charging amount A/C compressor for seizure Repair or replace the malfunctioning part according to the inspection results.
5	Remove the front climate control unit. See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION article. Reconnect the front climate control unit connector. Measure the voltage at the front climate control unit terminal 2H (wiring harness-side). Is the voltage normal? See FRONT CLIMATE CONTROL UNIT INSPECTION article.	Yes	Go to Step 7.
5		No	Go to next step.
6	Inspect the front evaporator temperature sensor. See FRONT EVAPORATOR TEMPERATURE SENSOR INSPECTION article. Is there any malfunction?	Yes	Replace the front evaporator temperature sensor. See FRONT EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION article.
6		No	Inspect for open or short circuit between front evaporator temperature sensor and front climate control unit. Repair or replace suspected wiring harness and connector.
7	Remove the front climate control unit. See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION article. Reconnect the front climate control unit connector. Start the engine and idle it. Measure the voltage at the front climate control unit terminal 2A (wiring harness-side) 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 FRONT CLIMATE CONTROL UNIT INSPECTION article. Specification Turn on the A/C: Below 1.0 V Turn off the A/C: Below.5 V	Yes	Replace the instrument cluster. (instrument cluster does not receive A/C request signal from climate control unit or transmit it to PCM.)
7		No	Go to the next step.
8	Inspect for open or short circuit between front climate control unit terminal 2A (wiring harness-side) and instrument cluster terminal 1C (wiring harness-side). Is there any malfunction?	Yes	Repair or replace suspected wiring harness and connector.
8		No	Replace the front climate control unit. (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.) See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION article.
9	Start the engine and idle it. Turn the PCM PID ACCS to ON from OFF using the M-MDS simulation function. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Measure the voltage at the magnetic clutch terminal A (wiring harness-side). Is the voltage specified? Specification 10.5 V or more	Yes	Go to the next step.
9		No	Go to step 11
10	Inspect for continuity between magnetic clutch terminal A (wiring harness-side) and body ground. Is there continuity?	Yes	Replace the A/C compressor. See A/C COMPRESSOR REMOVAL/INSTALLATION article.
10		No	Repair or replace suspected wiring harness and connector.
11	Inspect the A/C relay. See RELAY INSPECTION article. is there any malfunction?	Yes	Replace the A/C relay
11		No	Go to the next step
12	Switch the ignition to off. Disconnect the A/C relay and PCM connectors. Inspect for continuity between A/C relay and PCM terminal 1W (wiring harness-side) Is there continuity?	Yes	Inspect for open circuit between the following: Main relay No. 1 and A/C relay Battery positive terminal and A/C relay A/C relay and magnetic clutch Replace if necessary.
12		No	Repair or replace suspected wiring harness and connector.
13	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Retrieve the PCM and instrument cluster DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. See DTC INSPECTION [INSTRUMENT CLUSTER] article. Are there any DTCs displayed?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.) See DTC TABLE [INSTRUMENT CLUSTER] article.
1		No	Go to the next step.
2	Start the engine and idle it. Turn the A/C switch on. Remove the A/C relay. Does the A/C magnetic clutch disengage?	Yes	Go to step 4.
2		No	Go to the next step.
3	Turn the ignition switch to the LOCK position. Disconnect the magnetic clutch connector. Turn the ignition switch to the ON position. Measure the voltage at the magnetic clutch terminal A. Is the voltage B+ ?	Yes	Repair or replace suspected wiring harness and connector.
3		No	Replace the A/C compressor. (Magnetic clutch engagement is stuck.) See A/C COMPRESSOR REMOVAL/INSTALLATION article.
4	Inspect the A/C relay. See RELAY INSPECTION article. Is there any malfunction?	Yes	Replace the A/C relay.
4		No	Go to the next step.
5	Access the PCM PID ACCS using the M-MDS See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. 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	Go to the next step.
5		No	Inspect for short to ground in wiring harness between PCM terminal 1W and A/C relay. Repair or replace suspected wiring harness and connector.
6	Measure the voltage at the front climate control unit terminal 2A (wiring harness-side). Is the voltage always below 1.0 V ? See FRONT CLIMATE CONTROL UNIT INSPECTION article.	Yes	Go to the next step.
6		No	Replace the instrument cluster, (Instrument cluster always transmits A/C request signal from climate control unit to PCM.) See INSTRUMENT CLUSTER REMOVAL/INSTALLATION article.
7	Turn the ignition switch to the LOCK position. Disconnect the instrument cluster and front climate control unit connectors. Inspect for continuity between front climate control unit terminal 2A (wiring harness-side) and body ground. Is there continuity?	Yes	Repair or replace suspected wiring harness and connector.
7		No	Replace the front climate control unit. (A/C request signal is always on.) See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION article.
8	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Does A/C compressor disengage when the A/C switch is turned off?	Yes	Go to the next step.
1		No	Go to symptom troubleshooting "No. 24 A/C is always on or A/C compressor runs continuously". See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7] .
2	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
2		No	No DTC is displayed: Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7] article.) 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Are any driveability or exhaust smoke concerns present?	Yes	Go to the appropriate symptom troubleshooting. See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .
1	Are any driveability or exhaust smoke concerns present?	No	Go to the next step.
2	Inspect the following: Electrical connections Vacuum lines Fuel quality Are all items normal?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 2.
3	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
3		No	No DTC is displayed: Go to the next step.
4	Install the fuel pressure gauge between the fuel pipe and the fuel distributor. Start engine and run at idle. Measure the fuel line pressure during idle. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct during idle?	Yes	Go to the next step.
4		No	Zero or low: Inspect 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
5	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] article.
5		No	Inspect the fuel tank vent system. See FUEL TANK INSPECTION [MZI-3.7] article. 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 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
1		No	No DTC is displayed: Go to the next step.
2	Remove the fuel-filler pipe. Make sure the non return valve is installed properly. Inspect non return valve operation. Is the non return 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 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7] article.)
1		No	No DTC is displayed: Go to the next step.
2	Remove the fuel-filler pipe. Make sure the nonreturn valve is installed properly. Inspect nonreturn valve operation. Is the nonreturn valve normal?	Yes	Inspect for the following: Improper use of fuel nozzle Fuel is not inserted correctly. Inspect fuel shut-off valve. 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] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

STEP	INSPECTION	RESULTS	ACTION
1	Remove all the spark plugs. See SPARK PLUG REMOVAL/INSTALLATION [MZI-3.7] article. Inspect spark plug condition. See SPARK PLUG INSPECTION [MZI-3.7] article. Is 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	Are the spark plug wet/covered with carbon by the engine oil?	Yes	Inspect all areas related to oil, working up and down.
2		No	Go to the next step.
3	Inspect the spark plug for the following: Cracked insulator Heat range Air gap Worn electrode Is the spark plug normal?	Yes	Go to the next step.
3		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [MZI-3.7] article.)
4	Inspect compression pressure at suspected malfunctioning cylinder. (See COMPRESSION INSPECTION [MZI-3.7] article.) Is compression pressure correct?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	Install all spark plugs. Perform the spark test at suspected malfunctioning cylinder. See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] . 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 the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Inspect 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 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
7	Inspect the spark plug for the following. Heat range Air gap Is the spark plug normal?	Yes	Go to the next step.
7		No	Replace the spark plug. (See SPARK PLUG REMOVAL/INSTALLATION [MZI-3.7] article.)
8	Remove the suspected fuel injector. See FUEL INJECTOR REMOVAL/INSTALLATION [MZI-3.7] article. Inspect the following: Resistance Fuel injection volume (See FUEL INJECTOR INSPECTION [MZI-3.7] article.) Are all above items normal?	Yes	Inspect for open circuit in wiring harness between fuel injector connector terminal A and PCM at the following terminals: For No. 1 cylinder: 2BQ For No. 2 cylinder: 2BC For No. 3 cylinder: 2AY For No. 4 cylinder: 2BG For No. 5 cylinder: 2BL For No. 6 cylinder: 2BI Repair or replace the malfunctioning part according to the inspection results.
8		No	Replace the fuel injector. See FUEL INJECTOR REMOVAL/INSTALLATION [MZI-3.7] article.
9	Is the air cleaner element free of clogging?	Yes	Go to the next step.
9	Is the air cleaner element free of clogging?	No	Replace the air cleaner element.
10	Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) 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 the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Go to the next step.
11		No	Zero or low: Inspect the following: Fuel pump relay Fuel pump circuit Fuel line for clogging If there is no malfunction, replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
12	Access and monitor the following PCM PIDs using the M-MDS See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. 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] article.)	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning part according to the inspection results.
13	Perform the purge control inspection. (When engine can be started.) (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7] .) Is the purge control normal?	Yes	Go to the next step.
13		No	Repair or replace the malfunctioning part according to the inspection results.
14	Inspect the compression pressure. (See COMPRESSION INSPECTION [MZI-3.7] article.) Is the compression pressure normal?	Yes	Visually inspect for deformed exhaust system part. Repair or replace the malfunctioning part according to the inspection results.
14		No	Repair or replace the malfunctioning part according to the inspection results.
15	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 the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] article.) Is the fuel line pressure correct?	Yes	Access and monitor the following PCM PIDs using the M-MDS: See ON-BOARD DIAGNOSTIC TEST [MZI-3.7] article. ECT O2S11 O2S12 O2S21 O2S22 MAF Repair or replace the malfunctioning part according to the inspection results.
16		No	Zero or low: Inspect 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] article.) High: Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7] article.)
17	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7] .) If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7] article.)

DIAGNOSTIC PROCEDURE CHART

Inspection Method for Sensors

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

Scheme 9

Scheme 9: Inspection Method for Actuators or Relays

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

Input Signal System Inspection Procedure

Find an irregular signal. (See «FINDING IRREGULAR SIGNALS»(ref-663041-S27917932312014101600000) .)
Locate source. (See «LOCATING THE SOURCE OF UNUSUAL SIGNALS»(ref-663041-S17382354542014101600000) .)
Repair or replace the malfunctioning part.
Confirm that the irregular signal is no longer detected.

Input signal system inspection for variable resistance type 1

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 1

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

GND system inspection for variable resistance type 1

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

Scheme 10

Scheme 10: Variable resistance type 2 (mass air flow (MAF) sensor and VSS)

GND system inspection for variable resistance type 2

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

Input signal system inspection for variable resistance type 2

When an irregular signal is detected, measure the #1 PCM terminal voltage. If the #1 terminal voltage and the 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 the following points concerning the sensor connector: Female terminal opening is loose. Coupler (pin holder) damage Pin discoloration (blackness) Harness/pin crimp is loose or disconnected. If there are no problems, proceed to next investigation below.

Electrical supply system inspection for variable resistance type 2

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

Scheme 11

Scheme 11: 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 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]»(ref-663049-S42661457882014101600000) article.) Electronic throttle body and related wiring harness (See «THROTTLE BODY INSPECTION [MZI-3.7]»(ref-663036-S02163419042014101600000) article.)

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. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.) If P0506:00, P0507:00 are displayed, perform DTC inspection. (See «DTC TABLE [MZI-3.7]»(ref-663050-S00956222322014101600000) article.)
Access the PCM PID RPM. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.) 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 «FRONT CLIMATE CONTROL UNIT INSPECTION»(ref-663066-S38110385642014101600000) article.) Fan switch and related wiring harness (See «FRONT CLIMATE CONTROL UNIT INSPECTION»(ref-663066-S38110385642014101600000) article.)

Throttle position (TP) sweep inspection

Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position.
Verify that none of the following DTC are displayed: (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.) P0122:00, P0123:00, P0222:00, P0223:00, P2101:00, P2107:00, P2112:00, P2122:00, P2123:00, P2127:00, P2128:00, P2135:00 If any one DTC is displayed, perform DTC inspection. (See «DTC TABLE [MZI-3.7]»(ref-663050-S00956222322014101600000) article.)
Access TP1 TP2 PID. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.)
Verify that the PID reading is within the CTP value. (See «PCM INSPECTION [MZI-3.7]»(ref-663049-S38461691912014101600000) article.) If the PID reading is out of range, perform the following: Remove the air duct from the throttle valve body. Verify that the throttle valve opens when the accelerator pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. (See «THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7]»(ref-663049-S21298139132014101600000) article.) If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.
Gradually depress the throttle pedal and verify that the PID reading increases accordingly. If the PID reading drops momentarily, inspect the following: Throttle position sensor (See «THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7]»(ref-663049-S21298139132014101600000) article.)
Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See «PCM INSPECTION [MZI-3.7]»(ref-663049-S38461691912014101600000) article.) If the PID reading is out of range, perform the followings: Remove the air duct from throttle valve body. Verify that the throttle valve opens when throttle pedal is depressed. If the throttle valve opens, inspect the throttle position sensor and related wiring harness. (See «THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7]»(ref-663049-S21298139132014101600000) article.) If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.

Fuel Cut Control System Inspection

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

If simulation function of the M-MDS is used

Warm up the engine and idle it.
Connect the M-MDS to the DLC-2.
Access the PCM PIDs RPM and FUELSYS1. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.)
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 FUELSYS1 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]»(ref-663049-S42661457882014101600000) article.) TR switch and related wiring harness (See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AY6A-EL, AY6AX-EL] article.)

If simulation 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]»(ref-663049-S42661457882014101600000) article.) TR switch and related wiring harness (See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AY6A-EL, AY6AX-EL] article.)

Fuel Pump Control System Inspection

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

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	RESULTS	ACTION
1	Disconnect the ignition coil from the spark plugs. Remove the spark plugs. (See SPARK PLUG REMOVAL/INSTALLATION [MZI-3.7] article. Ensure that the spark plugs don't have carbon deposits. Are the spark plugs OK?	Yes	Go to the next step.
1		No	Perform 2 times of no-load racing at 4000 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.
2		No	Replace spark plugs, then go to the next step. (See SPARK PLUG REMOVAL/INSTALLATION [MZI-3.7] article.
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.
3		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 and replace the ignition coil. (See IGNITION COIL INSPECTION [MZI-3.7] article.) Repair or replace the malfunctioning part according to the inspection results.
4		No	Repair or replace suspected wiring harness and connector, then go to Step 1.
5	Turn the ignition switch to the ON position Measure the voltage at terminal A in each ignition coils. Is the voltage B+ ?	Yes	Go to the next step.
5		No	Inspect power supply circuit of ignition coils. Repair or replace suspected wiring harness and connector.
6	Verify continuity between each ignition coils terminal B and battery negative terminal. Is there any continuity?	Yes	Go to the next step.
6		No	Inspect GND circuit of ignition coils. Repair or replace suspected 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.
7		No	Go to the next step.
8	Is 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 suspected wiring harness and connector.
8	Is the CKP sensor and crankshaft pulley normal?	No	Repair or replace the malfunctioning part, then go to Step 1.

IGNITION SYSTEM INSPECT PROCEDURE CHART

Purge Control System Inspection

If simulation function of the M-MDS is used

Start the engine.
Disconnect the vacuum hose between the purge solenoid valve and the charcoal canister.
Put the finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold. If there is a vacuum, inspect the following: Wiring harness and connectors (Purge solenoid valve-PCM terminal 1BC) Purge solenoid vale (stuck open) (See PURGE SOLENOID VALVE INSPECTION [MZI-3.7] article.)
Connect the M-MDS to the DLC-2 and verify that the DTC P0443:00 is shown. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.) Perform the DTC inspection. (See «DTC TABLE [MZI-3.7]»(ref-663050-S00956222322014101600000) article.)
Access the PCM PID EVAPCP. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.)
Increase the duty value of the purge valve to 50 % and inspect if the operation sound of the valve is heard. If the operation sound is heard, inspect for the loose or damaged vacuum hose. (Intake manifold-Purge solenoid valve-Charcoal canister) If the operation sound is not heard, perform the purge solenoid valve inspection. (See PURGE SOLENOID VALVE INSPECTION [MZI-3.7] article.)
Warm up the engine to normal operating temperature. CAUTION: While performing step 8 with vehicle driving, 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.
Monitor the EVAPCP PID using the M-MDS, and drive the vehicle approx. 2,000 rpm for 30 sec. or more . If the EVAPCP PID is 0 % , inspect the following PCM PIDs: MAF, APP1, APP2, TP_REL and LOAD

If simulation function of the M-MDS is not used

Start the engine.
Disconnect the vacuum hose between the purge solenoid valve and the charcoal canister.
Put the finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold. If there is a vacuum, inspect the following: Wiring harness and connectors (Purge solenoid valve-PCM terminal 1BC) Purge solenoid vale (stuck open) (See PURGE SOLENOID VALVE INSPECTION [MZI-3.7] article.)
Connect the M-MDS to the DLC-2 and verify that the DTC P0443:00 is shown. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.) Perform the DTC inspection. (See «DTC TABLE [MZI-3.7]»(ref-663050-S00956222322014101600000) article.)
Access the PCM PID EVAPCP and ECT. (See «ON-BOARD DIAGNOSTIC TEST [MZI-3.7]»(ref-663050-S41925731952014101600000) article.)
Verify that the ECT PID is more than 78 °C {172 °F}. If the ECT PID reading indicates less than 78 °C {172 °F} , perform the ECT inspection.
Set the vehicle on the dynamometer or chassis roller. WARNING: When the dynamometer or chassis roller is operating, there is a possibility that the operator may come into contact with or be caught up in the rotating parts, leading to serious injuries or death. When performing work while the dynamometer or chassis roller is operating, be careful not to come into contact with or caught up in any of the rotating parts.
Drive the vehicle approx. 2,000 rpm for 30 sec. or more . If there is no vacuum, inspect the following: Wiring harness and connector (Main relay-purge solenoid valve-PCM terminal 1BC) Purge solenoid valve (See PURGE SOLENOID VALVE INSPECTION [MZI-3.7] article.) PCM PIDs MAF, APP1, APP2, TP_REL and LOAD If there is vacuum, inspect the following: Vacuum hose (Purge solenoid valve-Charcoal canister)

A/C Cut-off Control System Inspection

Start the engine.
Turn the A/C switch and the fan switch on.
Verify that the A/C compressor magnetic clutch actuates. If it does not actuate, go to symptom troubleshooting "No. 23 A/C does not work sufficiently". (See «NO. 23 A/C DOES NOT WORK SUFFICIENTLY [MZI-3.7]»(ref-663041-S22760719362014101600000) .)
Depress the accelerator pedal to WOT 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 article.) Open or short to GND circuit in wiring harness and connectors (A/C relay-PCM terminal 1W) A/C related parts PCM PIDs APP1, APP2

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]»(ref-663050-S16185617332014101600000) article.)
Verify the cooling fan operates during the KOER self-test.

Single fan control module

Cooling fans do not operate

Inspect the followings: Open circuit between the fan relay and battery positive terminal Open circuit between the fan relay and PCM terminal 1BI Open circuit between the fan relay and fan control module terminal 1C Open circuit between the control module terminal 1A and ground Fan control module (See «FAN CONTROL MODULE INSPECTION [MZI-3.7]»(ref-663017-S08571784642014101600000) article.) Open or short circuit between fan control module terminal 1B and PCM terminal 1BR Open or short circuit between ignition switch (IG1) and fan relay
If there is malfunction, repair or replace malfunctioning part.
If there is no malfunction, replace the fan control module. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

Cooling fan motor No. 1 does not operate

Inspect for followings: Open or short to ground circuit between the fan control module and cooling fan motor No. 1 Poor connection of the fan control module connector or cooling fan motor No. 1 connector Cooling fan motor No. 1 (See «FAN MOTOR INSPECTION [MZI-3.7]»(ref-663017-S10011863382014101600000) article.)
If there is malfunction, repair or replace malfunctioning part.
If there is no malfunction, replace the fan control module. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

Cooling fan motor No. 2 does not operate

Inspect for followings: Open or short to ground circuit between the fan control module and the cooling fan motor No. 2 Poor connection of the fan control module connector or the cooling fan motor No. 2 connector Cooling fan motor No. 2 (See «FAN MOTOR INSPECTION [MZI-3.7]»(ref-663017-S10011863382014101600000) article.)
If there is malfunction, repair or malfunctioning part.
If there is no malfunction, replace the fan control module. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

Dual fan control module

Cooling fans do not operate

Inspect for followings: Open circuit between cooling fan relay No. 1 and PCM terminal 1BI Open circuit between cooling fan relay No. 2 and PCM terminal 1BI Open or short circuit between fan control module No. 1 terminal 1B and PCM terminal 1BR Open or short circuit between fan control module No. 2 terminal 1B and PCM terminal 1BR
If there is malfunction, repair or replace malfunctioning part.
If there is no malfunction, replace the fan control module. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

Cooling fan motor No. 1 does not operate

Inspect for followings: Open or short to ground circuit between fan control module No. 1 and cooling fan motor No. 1 Poor connection of the fan control module No. 1 connector or cooling fan motor No. 1 connector Cooling fan motor No. 1 (See «FAN MOTOR INSPECTION [MZI-3.7]»(ref-663017-S10011863382014101600000) article.) Open or short circuit between ignition switch (IG1) and cooling fan relay No. 1 Cooling fan relay No. 1 malfunction (See RELAY INSPECTION article. Open circuit between fan relay No. 1 and battery positive terminal Open circuit between fan relay No. 1 and fan control module No. 1 terminal 1A Open circuit between fan control module No. 1 terminal 1C and ground Poor connection of the fan control module No. 1 connector
If there is malfunction, repair or replace malfunctioning part.
If there is no malfunction, replace the fan control module No. 1. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

Cooling fan motor No. 2 does not operate

Inspect for followings: Open or short to ground circuit between fan control module No. 2 and cooling fan motor No. 2 Poor connection of the fan control module No. 2 connector or cooling fan motor No. 2 connector Cooling fan motor No. 2 (See «FAN MOTOR INSPECTION [MZI-3.7]»(ref-663017-S10011863382014101600000) article.) Open or short circuit between ignition switch (IG1) and cooling fan relay No. 2 Cooling fan relay No. 1 malfunction (See RELAY INSPECTION article. Open circuit between fan relay No. 2 and battery positive terminal Open circuit between fan relay No. 2 and fan control module No. 2 terminal 1A Open circuit between fan control module No. 2 terminal 1C and ground Poor connection of the fan control module No. 2 connector
If there is malfunction, repair or replace malfunctioning part.
If there is no malfunction, replace the fan control module No. 2. (See «COOLING FAN COMPONENT REMOVAL/INSTALLATION [MZI-3.7]»(ref-663017-S08636677872014101600000) article.)

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 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.

Scheme 12

Scheme 12: EVAP system test description

Scheme 13

Scheme 14

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).

Scheme 15

Scheme 15: EVAP system malfunction judgment

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

Scheme 16

Scheme 16: Evaporative system test procedure

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 specification 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 17

Scheme 17: EVAP system leak inspection using leak tester

Scheme 18

Perform the following SST (EVAP System Tester 134-01049A) self-test: NOTE: If the tester does not work correctly during the self-test, refer to the tester operators service information for a more detailed self-test procedure. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle valve. Connect the vehicle interface hose (part of the SST ) to the SELF-TEST port located on the control panel. Hand tighten the fitting. (Do not overtighten.) Turn the control valve to the TEST position. The gauge should read 331-381 mm {13-15 in} of water. If the gauge is not reading in this range, adjust the pressure by turning the black knob on the low pressure regulator at the nitrogen bottle. Turn the control valve to the HOLD position. Verify that the gauge holds pressure and that the flow meter reads no flow. If there is no drop in pressure and no flow, the tester passes the self-test. If the gauge leaks down, refer to the tester operators service information.
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.
Turn the ignition switch to the ON position (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: The engine is started. The ignition switch is turned off position.
Make sure the control valve on the 134-01049A is in the HOLD position and that the valve on the cylinder of nitrogen gas is open.
Turn the control valve to the open position and let the system fill. You should note a drop in the gauge pressure along with the flow meter being pegged at maximum flow for several minutes depending on how full or empty the fuel tank is, and how long it takes to completely fill and pressurize the evaporative emissions system hoses.
If the gauge and the flow meter do not settle to a measurable level after 2-3 min , then refer to the Mazda Service Information 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 evaporative emissions leak: NO EVAPORATIVE LEAK: The flow meter registers "zero flow" and the pressure gauge returns to the pre-set pressure of 356 mm {14 in} of water (H2O). EVAPORATIVE LEAK: The pressure does not return to the preset level of 356 mm {14 in} of water (H2O) when measuring the flow. See "SETTING LEAK STANDARD FOR TESTING" (.020 to.040 inch H2O) of the Evaporative Emissions Tester operators service information (134-01067). warn. NOTE: Turn the control valve to the HOLD position then disconnect the SST.

Symptom Troubleshooting [Engine Controls MZI-3.7]: Diagnosis Mazda CX-9 I рестайлинг

SYMPTOM DIAGNOSTIC INDEX [MZI-3.7]

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Diagnostic Procedure

Inspection Method for Sensors

Scheme 9

Input Signal System Inspection Procedure

Input signal system inspection for variable resistance type 1

Standard power supply system inspection for variable resistance type 1

GND system inspection for variable resistance type 1

Scheme 10

GND system inspection for variable resistance type 2

Input signal system inspection for variable resistance type 2

Electrical supply system inspection for variable resistance type 2

Scheme 11

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

Fuel Pump Control System Inspection

Spark Test

Purge Control System Inspection

A/C Cut-off Control System Inspection

Cooling Fan Control System Inspection

Evaporative Emission (EVAP) System Leak Inspection

EVAP system test out line

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

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