DIAGNOSIS FUNCTION

ENGINE WARNING LAMP (CHECK ENGINE LAMP)

If an abnormality occurs in any of the following items related to the Multipoint Fuel Injection (MPI) system, the engine warning lamp will illuminate.
If the lamp remains illuminated or if the lamp illuminates while the engine is running, check the diagnosis code output.

ENGINE WARNING LAMP INSPECTION ITEMS

Code No.	Diagnosis item
-	Engine-A/T-ECU
P0075	Oil control valve system
P0100	Air flow sensor system
P0105	Barometric pressure sensor system
P0110	Intake air temperature sensor system
P0115	Engine coolant temperature sensor system
P0120	Throttle position sensor (main) system
P0130	Cylinder 1, 4 oxygen sensor (front) system
P0135	Cylinder 1, 4 oxygen sensor (front) heater system
P0136	Cylinder 1, 4 oxygen sensor (rear) system
P0141	Cylinder 1, 4 oxygen sensor (rear) heater system
P0150	Cylinder 2, 3 oxygen sensor (front) system
P0155	Cylinder 2, 3 oxygen sensor (front) heater system
P0156	Cylinder 2, 3 oxygen sensor (rear) system
P0161	Cylinder 2, 3 oxygen sensor (rear) heater system
P0170	Abnormal fuel system (cylinder 1, 4)
P0173	Abnormal fuel system (cylinder 2, 3)
P0201	No. 1 injector system
P0202	No. 2 injector system
P0203	No. 3 injector system
P0204	No. 4 injector system
P0220	Accelerator pedal position sensor (main) system
P0225	Throttle position sensor (sub) system
P0300	Ignition coil (power transistor) system
P0325	Detonation sensor system
P0335	Crank angle sensor system
P0340	Camshaft position sensor system
P0403	Exhaust gas recirculation control system
P0500	Vehicle speed signal system
P0513	Immobilizer malfunction
P0551	Power steering fluid pressure sensor system
P0603	EEP ROM system
P0606	Microcomputer malfunction
P0622	Alternator FR terminal system
P0638	Throttle valve control servo circuit range/performance problem
P1121	Throttle valve control servo power system
P1122	Throttle valve control servo connector system
P1221	Throttle valve position feedback system
P1223	Communication line system with the throttle valve controller
P1225	Accelerator pedal position sensor (sub) system
P1603	Battery backup circuit malfunction

note

When the electronic-controlled throttle valve system is stopped by the fail-safe function, the engine warning lamp (check engine lamp) is illuminated.

METHOD OF READING AND ERASING DIAGNOSIS CODES

Refer to

, GROUP 00 - How to Use Troubleshooting/Inspection Service Points.

DIAGNOSIS USING DIAGNOSIS 2 MODE

Switch the diagnosis mode of the engine control unit to DIAGNOSIS 2 mode using the M.U.T.-III.
Carry out a road test.
Take a reading of the diagnosis code and repair the problem location.

Turn the ignition switch to OFF and then back to ON again.

note

By turning the ignition switch to OFF, the engine-A/T-ECU will switch the diagnosis mode from DIAGNOSIS 2 mode to DIAGNOSIS 1 mode.

Erase the diagnosis codes.

INSPECTION USING M.U.T.-III DATA LIST AND ACTUATOR TESTING

1.Carry out inspection by means of the data list and the actuator test function, if there is an abnormality, check and repair the chassis harness and components.

2.After repairing, re-check using the M.U.T.-III and check that the abnormal input and output have returned to normal as a result of the repairs.

3.Erase the diagnosis code memory.

4.Remove the M.U.T.-III, and then start the engine again and carry out a road test to confirm that the problem has disappeared.

FREEZE FRAME DATA

When the engine-A/T-ECU detects a malfunction and stores a diagnosis code, it also stores a current status of the engine. This function is called "Freeze frame data". By analyzing this "Freeze frame" data with the M.U.T.-III, an effective troubleshooting can be performed.

The display items of freeze frame data are shown below.

DISPLAY ITEM LIST

Item No.	Data		Unit
21	Engine coolant temperature sensor		°C
22	Crank angle sensor		r/min
24	Vehicle speed		km/h
81	Long-term fuel compensation (cylinder 1, 4)		%
82	Short-term fuel compensation (cylinder 1, 4)		%
83	Long-term fuel compensation (cylinder 2, 3)		%
84	Short-term fuel compensation (cylinder 2, 3)		%
87	Calculation load value		%
88	Fuel control condition (cylinder 1, 4)	Open loop	OL
		Closed loop	CL
		Open loop owing to drive condition	OL-DRV.
		Open loop owing to system malfunction	OL-SYS.
89	Fuel control condition (cylinder 2, 3)	Open loop	OL
		Closed loop	CL
		Open loop owing to drive condition	OL-DRV.
		Open loop owing to system malfunction	OL-SYS.
-	Diagnosis code during data recording		-

note

If malfunctions have been detected in multiple systems, store one malfunction only, which has been detected first.

FAIL-SAFE FUNCTION REFERENCE TABLE

When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled by means of the pre-set control logic to maintain safe conditions for driving.

Malfunctioning item	Control contents during malfunction
Intake air temperature sensor	Controls as if the intake air temperature is 25°C.
Barometric pressure sensor	Controls as if the barometric pressure is 101 kPa.
Throttle position sensor (main)	Controls the throttle valve position through the use of the throttle position sensor (sub) signal. Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle. Prohibits the operation of the engine speed feedback control. Cuts off fuel when the engine speed exceeds 3,000 r/min. Suppresses the engine output by stopping the electronic-controlled throttle valve system if the throttle position sensor (sub) is also malfunctioning.
Throttle position sensor (sub)	Controls the throttle valve position through the use of the throttle position sensor (main) signal. Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle. Cuts off fuel when the engine speed exceeds 3,000 r/min. Suppresses the engine output by stopping the electronic-controlled throttle valve system if the throttle position sensor (main) is also malfunctioning.
Accelerator pedal position sensor (main)	Detects the amount of the accelerator pedal travel through the use of the accelerator pedal position sensor (sub) signal, but rendering it only as being approximately one-half the normal opening angle. Cuts off fuel when the engine speed exceeds 3,000 r/min. Suppresses the engine output by stopping the electronic-controlled throttle valve system if the accelerator pedal position sensor (sub) is also malfunctioning.
Accelerator pedal position sensor (sub)	Detects the amount of the accelerator pedal travel through the use of the accelerator pedal position sensor (main) signal, but rendering it only as being approximately one-half the normal opening angle. Cuts off fuel when the engine speed exceeds 3,000 r/min. Suppresses the engine output by stopping the electronic-controlled throttle valve system if the accelerator pedal position sensor (main) is also malfunctioning.
Engine coolant temperature sensor	Controls as if the engine coolant temperature is 80°C. (This control will be continued until the ignition switch is turned to the "LOCK" (OFF) position even though the sensor signal returns to normal.)
Camshaft position sensor	The control condition before the fail is determined is continued. After 4 seconds pass from when the malfunction is detected, the fuel is shut off. (After the ignition switch is turned to ON position, the No.1 cylinder top dead center is no detected at all.)
Detonation sensor	The ignition timing is set having enough time against knocking.
Ignition coil (incorporating power transistor)	Cuts off the fuel supply to cylinders with an abnormal ignition.
Alternator FR terminal	Does not control the output of the alternator according to an electrical load. (works as a normal alternator)
Throttle valve position feedback	Suppresses the engine output by stopping the electronic-controlled throttle valve system.
Throttle valve control servo	Suppresses the engine output by stopping the electronic-controlled throttle valve system.
Throttle valve control microcomputer	Suppresses the engine output by stopping the electronic-controlled throttle valve system.
Communication between throttle valve control microcomputer and engine control microcomputer	Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle. Cuts off fuel when the engine speed exceeds 3,000 r/min.