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

SYMPTOM MATRIX CHART - BASIC ENGINE CONTROL SYSTEM

		SYMPTOM													Refer to
		HARD/NO START/RESTART (EXCP. HA)	ENGINE STALL	HESITATION/SURGING/FLAT SPOT	SPARK KNOCK/DETONATION	LACK OF POWER/POOR ACCELERATION	HIGH IDLE/LOW IDLE	ROUGH IDLE/HUNTING	IDLING VIBRATION	SLOW/NO RETURN TO IDLE	OVERHEATS/WATER TEMPERATURE HIGH	EXCESSIVE FUEL CONSUMPTION	EXCESSIVE OIL CONSUMPTION	BATTERY DEAD (UNDER CHARGE)
Warranty symptom code		AA	AB	AC	AD	AE	AF	AG	AH	AJ	AK	AL	AM	HA
Fuel	Fuel pump circuit	1	1	2	3	2		2	2			3		2	DTC P1220 FUEL PUMP CONTROL MODULE (FPCM) , FUEL PUMP CIRCUIT ,
	Fuel pressure regulator system	3	3	4	4	4	4	4	4	4		4			DIAGNOSTIC PROCEDURE
	Injector circuit	1	1	2	3	2		2	2			2			INJECTOR CIRCUIT
	Evaporative emission system	3	3	4	4	4	4	4	4	4		4			EVAPORATIVE EMISSION SYSTEM
Air	Positive crankcase ventilation system	3	3	4	4	4	4	4	4	4		4	1		POSITIVE CRANKCASE VENTILATION
	Incorrect idle speed adjustment	3	3				1	1	1	1		1			BASIC SERVICE PROCEDURE
	Electric throttle control actuator	1	1	2	3	3	2	2	2	2		2		2	DTC P1121 ELECTRIC THROTTLE CONTROL ACTUATOR , DTC P1122 ELECTRIC THROTTLE CONTROL FUNCTION , DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAY , DTC P1128 THROTTLE CONTROL MOTOR
Ignition	Incorrect ignition timing adjustment	3	3	1	1	1		1	1			1			BASIC SERVICE PROCEDURE
Ignition	Ignition circuit	1	1	2	2	2		2	2			2			IGNITION SIGNAL
Main Power supply and ground circuit		2	2	3	3	3		3	3		2	3			POWER SUPPLY AND GROUND CIRCUIT
Mass air flow sensor circuit		1	1	2	2	2		2	2			2			DTC P0101 MAF SENSOR , DTC P0102, P0103 MAF SENSOR
Engine coolant temperature sensor circuit		1			3		3			3					DTC P0117, P0118 ECT SENSOR , DTC P0125 ECT SENSOR
Air fuel ratio (A/F) sensor 1 circuit					3										DTC P1271, P1281 A/F SENSOR 1 , DTC P1272, P1282 A/F SENSOR 1 , DTC P1273, P1283 A/F SENSOR 1 , DTC P1274, P1284 A/F SENSOR 1 , DTC P1276, P1286 A/F SENSOR 1 , DTC P1278, P1288 A/F SENSOR 1 , 527
Throttle position sensor circuit							2			2					DTC P0122, P0123 TP SENSOR , DTC P0222, P0223 TP SENSOR , DTC P1225 TP SENSOR , DTC P1226 TP SENSOR , DTC P2135 TP SENSOR
Accelerator pedal position sensor circuit				3	2	1	2			2					DTC P1279, P1289 A/F SENSOR 1 , DTC P2122, P2123 APP SENSOR , DTC P2122, P2123 APP SENSOR , 600
Knock sensor circuit				2								3			DTC P0327, P0328, P0332, P0333 KS
Crankshaft position sensor (POS) circuit		2	2												DTC P0335 CKP SENSOR (POS)
Camshaft position sensor (PHASE) circuit		3	2												DTC P0340 CMP SENSOR (PHASE)
Vehicle speed signal circuit			2	3		3						3			DTC P0550 PSP SENSOR
Power steering pressure sensor circuit			2					3	3						DTC P0550 PSP SENSOR
ECM		2	2	3	3	3	3	3	3	3	3	3			DTC P0605 ECM , DTC P1065 ECM POWER SUPPLY
Park/neutral position (PNP) switch circuit				3		3		3	3			3			DTC P1706 PNP SWITCH
Refrigerant pressure sensor circuit			2				3			3		4			REFRIGERANT PRESSURE SENSOR
Electrical load signal circuit								3							ELECTRICAL LOAD SIGNAL
Air conditioner circuit		2	2	3	3	3	3	3	3	3		3		2	MTC-28
ABS actuator and electric unit (control unit)				4											DTC P1211 TCS CONTROL UNIT , DTC P1212 TCS COMMUNICATION LINE or BRC-97

1 - 6: The numbers refer to the order of inspection.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

System - Basic Engine Control System

Use the Manual With the Right Hardware

When to See a Mechanic

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