DIAGNOSIS FUNCTION

ENGINE WARNING LAMP (CHECK ENGINE LAMP)

When the abnormal condition occurs with respect to the items of Multipoint Fuel Injection (MPI) system shown in the table, the engine warning lamp is illuminated. When the lamp remains illuminated after the engine start, or when the lamp is illuminated while the engine is running, check the diagnosis code output. There are two methods for checking the indicator lamp burn out: When the ignition switch is in ON position, the indicator lamp is illuminated, and then extinguished few seconds later. When the ignition switch is in ON position and the engine starts, the indicator lamp is extinguished.

ENGINE WARNING LAMP INSPECTION ITEMS

caution

The engine warning lamp continuously illuminates when the engine-ECU malfunctions.

Code No.	Diagnosis item
P0105	Manifold absolute pressure sensor system
P0110	Intake air temperature sensor system
P0115	Engine coolant temperature sensor system
P0122^*1	Throttle position sensor (main) circuit low input
P0123^*1	Throttle position sensor (main) circuit high input
P0125^*1	Insufficient coolant temperature for closed loop fuel control
P0130	Oxygen sensor (front) system
P0133	Oxygen sensor (front) circuit slow response
P0134^*1	Oxygen sensor (front) circuit no activity detected
P0135	Oxygen sensor (front) heater system
P0136	Oxygen sensor (rear) system
P0141	Oxygen sensor (rear) heater system
P0170	Abnormal fuel system
P0201	No. 1 injector system
P0202	No. 2 injector system
P0203	No. 3 injector system
P0204	No. 4 injector system
P0222^*1	Throttle position sensor (sub) circuit low input
P0223^*1	Throttle position sensor (sub) circuit high input
P0300^*2	Random/multiple cylinder misfire detected
P0301^*2	No. 1 cylinder misfire detected
P0302^*2	No. 2 cylinder misfire detected
P0303^*2	No. 3 cylinder misfire detected
P0304^*2	No. 4 cylinder misfire detected
P0335^*1	Crank angle sensor system
P0340^*1	Camshaft position sensor system
P0420	Catalyst malfunction <M/T>
P0421	Catalyst malfunction <A/T>
P0443	Purge control solenoid valve system
P0500^*1	Vehicle speed sensor system <M/T>
P0603^*1	EEPROM malfunction
P0606^*1	Engine-ECU main processor malfunction
P0630^*1	Chassis number not programmed
P0638^*1	Throttle valve control servo circuit range/performance problem
P0642^*1	Throttle position sensor power supply
P0657^*1	Throttle valve control servo relay circuit malfunction
P1021	Oil feeder control valve system
P1233^*1	Trustful check throttle position sensor (main)
P1234^*1	Trustful check throttle position sensor (sub)
P1235^*1	Trustful check manifold absolute pressure sensor
P1236^*1	A/D converter
P1237^*1	Trustful check accelerator pedal position sensor
P1238^*1	Manifold absolute pressure sensor trustful for torque monitoring
P1239^*1	Trustful check engine speed
P1241^*1	Torque monitoring
P1603^*1	Battery backup circuit malfunction
P1676^*1	Variant coding system
P2100^*1	Throttle valve control servo circuit (open)
P2101^*1	Throttle valve control servo magneto malfunction
P2122^*1	Accelerator pedal position sensor (main) circuit low input
P2123^*1	Accelerator pedal position sensor (main) circuit high input
P2127^*1	Accelerator pedal position sensor (sub) circuit low input
P2128^*1	Accelerator pedal position sensor (sub) circuit high input
P2135^*1	Throttle position sensor (main and sub) range/performance problem
P2138^*1	Accelerator pedal position sensor (main and sub) range/performance problem
U0101^*1	A/T-ECU time-out <A/T>
U0141^*1	ETACS-ECU time-out

note

After the engine-ECU 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 "^*1" in the diagnosis code number column, the engine warning lamp illuminates only on the first detection of the malfunction.

note

The codes marked with a "^*2" in the diagnosis code number column have the following two conditions for illuminating the engine warning lamp.

In case that the misfire causing the damaged catalyst is detected, the engine warning lamp is illuminated at the time.
In case that the misfire deteriorating the exhaust gas is detected, the engine warning lamp is illuminated when the same malfunction is redetected after the next engine start.

note

After the engine warning lamp illuminates, it will be switched off under the following conditions.

When the engine-ECU monitored the malfunction three times* and met set condition requirements, it detected no malfunction.

For misfiring or a fuel trim malfunction, when driving conditions (engine speed, engine coolant temperature, etc.) are similar to those when the malfunction was first recorded.
The illuminated engine warning lamp for the chassis number related faults is extinguished when the chassis number is detected.

METHOD OF READING AND ERASING DIAGNOSIS CODES

Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - Diagnosis Function

DIAGNOSIS IN DIAGNOSIS SENSITIVITY-UP MODE

When the diagnosis sensitivity-up mode is selected in M.U.T.-III, the engine-ECU illuminates the engine warning lamp and enters into the mode to store the corresponding diagnosis code upon detecting a failure. Time for judgment from occurrence of a malfunction to storing of a diagnosis code is shortened (from 4 seconds to 1 second). This function reduces work for checking a malfunction phenomenon and repair completion after repair. To return to the sensitivity standard mode after selecting the diagnosis sensitivity-up mode, it is necessary either to turn the ignition key to "LOCK" (OFF) or to reselect the sensitivity standard mode on M.U.T.-III. The diagnosis codes and freeze frame data stored in the sensitivity-up mode are automatically erased when the mode is returned to the sensitivity standard mode. If they are needed, record them beforehand.

DIAGNOSIS PROCEDURE

Connect M.U.T.-III and switch the diagnosis mode of the engine-ECU to the diagnosis sensitivity-up mode to perform a test run.
Read the diagnosis code and repair the malfunctioning part.
Select the sensitivity standard mode on M.U.T.-III or turn the ignition switch to the ON position again after turning it to "LOCK" (OFF) position once.

note When the ignition switch is turned to the "LOCK" (OFF) position, the engine-ECU switches the diagnosis mode from diagnosis sensitivity-up mode to diagnosis standard mode.

INSPECTION WITH M.U.T.-III SERVICE DATA AND ACTUATOR TEST

Reading service data or performing an actuator test using M.U.T.-III enables you to check the vehicle body harnesses and components for abnormalities. Sensor input or output to the actuator can be displayed in numerical values or graphs in the service data while in the actuator test the actuator can be forced to drive (ON/OFF driving in the specified time).

DIAGNOSIS PROCEDURE

Connect M.U.T.-III to perform inspection with the service data and actuator test function.
If any abnormality is found, inspect and repair vehicle body harnesses and components.
After repair, check that input and output have returned to normal.
If a failure code which is caused by inspection and repair work is generated, erase the failure code.
Disconnect M.U.T.-III and perform a test run to check that the malfunction phenomenon is resolved.

FREEZE FRAME DATA

DISPLAY ITEM LIST

Item No.	Date Item	Unit·Condition
1	Odometer	km
2	Ignition cycle (Warm up cycle)	-
4	Accumulated minute^*1	min
AB^*2	Throttle position sensor (main)	%
BB^*2	Barometric pressure sensor	kPa
BC^*2	Relative throttle position sensor	%
BD^*2	Throttle position sensor (sub)	%
BE^*2	Accelerator pedal position sensor (main)	%
BF^*2	Accelerator pedal position sensor (sub)	%
C0^*2	Fuel system status 1	CL (closed loop)^3 OL (open loop)^4 OL - Drv (condition of open loop due to acceleration and deceleration driving) OL -Fault (condition of open loop due to system failure) CL -Fault (condition of closed loop only using front oxygen sensor when rear oxygen sensor is failed)
C1^2^5	Fuel system status 2	N/A
C2^*2	Calculated load valve	%
C3^*2	Engine coolant temperature sensor	°C
C4^*2	Short term fuel trim 1	%
C5^2^5	Short term fuel trim 3	****
C6^*2	Long term fuel trim 1	%
C7^2^5	Long term fuel trim 3	****
CC^*2	Manifold absolute pressure sensor	kPa
CD^*2	Crank angle sensor	r/min
CE^*2	Vehicle speed	km/h
CF^*2	Advance ignition	°CA
D0^*2	Intake air temperature sensor	°C
D1^*2	Time since engine running^*6	sec
D6^*2	Purge solenoid duty	%
D8^*2	Power supply voltage	V
D9^*2	Absolute load value	%
DA^*2	Target equivalence ratio	-
DB^*2	Intake air temperature sensor	°C
DC^*2	Commanded throttle actuator control	%

note

^*1: Accumulated time of current malfunction from time point when malfunction is detected.

note

^*2: The items of Freeze Frame Data can be seen by selecting "Freeze Frame Data (OBD)" on "Self-diagnosis" screen of M.U.T.-III. When system malfunctions are detected, the first detected malfunction data only is stored.

note

^*3: Condition in which oxygen sensor signals are fed back to the engine-ECU for controlling fuel

note

^*4: Condition in which fuel is controlled without oxygen sensor signals being fed back to the engine-ECU because the condition to shift to the closed loop is not met.

note

^*5: Data items are displayed on M.U.T.-III display, but the in-line 4 engine is not applicable and its data is displayed as "N/A" or "****".

note

^*6: Time between engine start and malfunction detection

FAIL-SAFE FUNCTION REFERENCE TABLE

List of fail-safe and backup function items

Code No.	Diagnosis item	Control content during malfunction
P0115	Engine coolant temperature sensor system	Control as if the engine coolant temperature is 80°C.
P0122	Throttle position sensor (main) circuit low input	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (sub) fails.
P0123	Throttle position sensor (main) circuit high input	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (sub) fails.
P0125	Insufficient coolant temperature for closed loop fuel control	Control as if the engine coolant temperature is 80°C.
P0222	Throttle position sensor (sub) circuit low input	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (main) fails.
P0223	Throttle position sensor (sub) circuit high input	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (main) fails.
P0300	Random/multiple cylinder misfire detected	The supply of fuel to the misfiring cylinder can possibly be cut.
P0301	No. 1 cylinder misfire detected	The supply of fuel to the misfiring cylinder can possibly be cut.
P0302	No. 2 cylinder misfire detected	The supply of fuel to the misfiring cylinder can possibly be cut.
P0303	No. 3 cylinder misfire detected	The supply of fuel to the misfiring cylinder can possibly be cut.
P0304	No. 4 cylinder misfire detected	The supply of fuel to the misfiring cylinder can possibly be cut.
P0325	Detonation sensor system	Fix the ignition timing with an allowance against detonation.
P0340	Camshaft position sensor system	Engine runs in learned pattern until engine stops. Does not control variable valve timing (V.V.T.).
P0513	Immobilizer system	Engine start is prohibited.
P0606	Engine-ECU main processor malfunction	Throttle opening degree position is in default position.
P0622	Alternator FR terminal system	Prohibits alternator output suppression control against current consumers (operates as a normal alternator).
P0638	Throttle valve control servo circuit range/performance problem	Throttle opening degree position is in default position.
P0642	Throttle position sensor power supply	Throttle opening degree position is in default position.
P0657	Throttle valve control servo relay circuit malfunction	Throttle opening degree position is in default position.
P1021	Oil feeder control valve system	V.V.T. phase angle becomes most retarded angle.
P1231	Trustful check active stability control (ASC) <Vehicles with ASC>	Torque requested by active stability control (ASC) is ignored.
P1232	Fail-safe control system	Microcomputer is reset.
P1233	Trustful check throttle position sensor (main)	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (sub) fails.
P1234	Trustful check throttle position sensor (sub)	Throttle opening degree is restricted. Throttle opening degree position is in default position if throttle position sensor (main) fails.
P1235	Trustful check manifold absolute pressure sensor	Fuel control is carried out using throttle opening degree and engine speed in accordance with preset map.
P1236	A/D converter	Throttle opening degree position is in default position.
P1237	Trustful check accelerator pedal position sensor	Throttle opening degree position is in default position.
P1238	Manifold absolute pressure sensor trustful for torque monitoring	Throttle opening degree position is in default position.
P1239	Trustful check engine speed	Throttle opening degree position is in default position.
P1240	Trustful check ignition angle <Vehicles with ASC>	Ignition retard is not carried out
P1241	Torque monitoring	Throttle opening degree position is in default position.
P1242	Fail safe control monitoring	Throttle opening degree position is in default position.
P1243	Inquiry/response error	Microcomputer is reset.
P1244	RAM test for all area	Microcomputer is reset.
P1245	Cyclic RAM test (engine)	Microcomputer is reset.
P1247	Trustful check A/T <A/T>	Torque requested by A/T-ECU is ignored.
P1603	Battery backup circuit malfunction	All diagnosis codes are stored once failure judgment is completed.
P2100	Throttle valve control servo circuit (open)	Throttle opening degree position is in default position.
P2101	Throttle valve control servo magneto malfunction	Throttle opening degree position is in default position.
P2122	Accelerator pedal position sensor (main) circuit low input	Throttle opening degree is restricted. Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.
P2123	Accelerator pedal position sensor (main) circuit high input	Throttle opening degree is restricted. Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.
P2127	Accelerator pedal position sensor (sub) circuit low input	Throttle opening degree is restricted. Throttle opening degree position is in default position if accelerator pedal position sensor (main) fails.
P2128	Accelerator pedal position sensor (sub) circuit high input	Throttle opening degree is restricted. Throttle opening degree position is in default position if accelerator pedal position sensor (main) fails.
P2135	Throttle position sensor (main and sub) range/performance problem	Throttle opening degree position is in default position.
P2138	Accelerator pedal position sensor (main and sub) range/performance problem	Throttle opening degree is restricted. Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.
U0167	KOS-ECU <Vehicles with KOS> or WCM <Vehicles with WCM> communication error	Engine start is prohibited.