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-ECU <M/T> or engine-A/T-ECU <A/T>
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 system
P0135*	Cylinder 1, 4 oxygen sensor heater system
P0150*	Cylinder 2, 3 oxygen sensor system
P0155*	Cylinder 2, 3 oxygen sensor 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
P0606*	Engine-ECU <M/T> or engine-A/T-ECU <A/T> main processor malfunction
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
U1108*	Combination meter time-out

note

If the engine warning lamp illuminates because of a malfunction of the engine-ECU <M/T> or engine-A/T-ECU <A/T>, communication between M.U.T.-III and the engine-ECU <M/T> or engine-A/T-ECU <A/T> is impossible. In this case, the diagnosis code cannot be read.
After the engine-ECU <M/T> or engine-A/T-ECU <A/T> has detected a malfunction, the engine warning lamp illuminates when the engine is next turned on and the same malfunction is re-detected. However, for items marked with a "*" in the diagnosis code number column, the engine warning lamp illuminates only on the first detection of the malfunction.
After the engine warning lamp illuminates, it will be switched off under the following conditions.

When the engine-ECU <M/T> or engine-A/T-ECU <A/T> monitored the power train malfunction three times* met set condition requirements, it detected no malfunction.
*: In this case, "one time" indicates from engine start to stop.

For misfiring malfunction, when driving conditions (engine speed, engine coolant temperature, etc.) are similar to those when the malfunction was first recorded.
Sensor 1 indicates, the sensor mounted at a position closest to the engine, and sensor 2 indicates the sensor mounted at the position second closest to the engine.

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-ECU <M/T> or ENGINE-A/T-ECU <A/T> 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.

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
Air flow sensor	Uses the throttle position sensor signal and engine speed signal (crankshaft position sensor signal) for basic injector drive time and basic ignition timing from the pre-set mapping.
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	Injects fuel into the cylinders in the order 1-3-4-2 with irregular timing. (After the ignition switch is turned to the “ON” position, the No. 1 cylinder top dead center is not detected at all.)
Oxygen sensor	Air/fuel ratio closed loop control is not performed.
Detonation sensor	Switches the ignition timing from ignition timing for high octane to ignition timing for standard octane fuel.
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)
Misfiring	If the detected misfiring causes damage to the catalyst, the misfiring cylinder will be shut down.
Throttle valve position feedback	Suppresses the engine output by stopping the electronic-controlled throttle valve system. Prohibits the operation of the engine speed feedback control.
Throttle valve control servo	Suppresses the engine output by stopping the electronic-controlled throttle valve system. Prohibits the operation of the engine speed feedback control.
Engine-ECU <M/T> or engine-A/T-ECU <A/T> main processor	Suppresses the engine output by stopping the electronic-controlled throttle valve system. Prohibits the operation of the engine speed feedback control.
Communication between powertrain control module main processor and system LSI	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.
Intake air monitor	Suppresses the engine output by stopping the electronic-controlled throttle valve system. Prohibits the operation of engine speed feedback.
Oil control valve	Do not switch to high-speed cam. Cut off fuel when the engine speed exceeds 5,000 r/min.