FAIL SAFE
If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.
Scheme 551
If the Electronic Throttle Control System (ETCS) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.
Scheme 552
| Item | Specification |
|---|---|
| The monitor will run whenever the following DTCs are not present | See "List of disable a monitor" ( PRE-CHECK ). |
TYPICAL ENABLING CONDITIONS
| Detection Criteria | Threshold |
|---|---|
| VTA1 - (VTA2 x 0.8)| (1) | Less than 0.1 V and more than 0.4 V |
| (1) Corrected by learning value. | |
| (1) | Corrected by learning value. |
TYPICAL MALFUNCTION THRESHOLDS
| Detection Criteria | Threshold |
|---|---|
| Time until "engine coolant temperature" detection temperature reaches feedback start temperature | |
| When the temperature at the time of engine starting is 10°C (50°F) or more | Engine coolant temperature is less than "closed-loop enable temperature" when 2 min. or more after engine start |
| When the temperature at the time of engine starting is "-6.6°C (20°F)" to "10°C (50°F)" | Engine coolant temperature is less than "closed-loop enable temperature" when 5 min. or more after engine start |
| When the temperature at the time of engine starting is -6.6°C (20°F) or less | Engine coolant temperature is less than "closed-loop enable temperature" when 20 min. or more after engine start |
TYPICAL MALFUNCTION THRESHOLDS
| Detection Criteria | Threshold |
|---|---|
| Duration period of both A and B | 5 sec. or more |
| A Estimated engine coolant temperature | 75°C (167°F) or more |
| B Engine coolant temperature sensor output value | Less than 75°C (167°F) |
TYPICAL MALFUNCTION THRESHOLDS
The detailed information is described in "CHECKING MONITOR STATUS" (see PRE-CHECK ).
- TID (Test Identification) is assigned to each emission-related component.
- TLT (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
- CID (Component Identification) is assigned to each test value.
- Unit Conversion is used to calculate the test value indicated on generic OBD scan tools.
TID $08: Thermostat
| TLT | CID | Unit Conversion | Description of Test Value | Description of Test Limit |
|---|---|---|---|---|
| 1 | $01 | Multiply by 0.625 and subtract 40 (°C) | ECT sensor output when estimated ECT reaches malfunction criterion | Malfunction criterion |
THERMOSTAT MALFUNCTION CHECK
| Detection Criteria | Threshold |
|---|---|
| P0130, P0150 | |
| Either of the following conditions A or B is met | 3 times or more |
| A. Front oxygen sensor voltage is 0.55 V or less | For 18 sec. or more |
| B. Front oxygen sensor voltage is 0.4 V or more | For 18 sec. or more |
| P2195, P2197 | |
| Front heated oxygen sensor voltage | Constant 0.55 V or less |
| P2196, P2198 | |
| Front heated oxygen sensor voltage | Constant 0.4 V or more |
TYPICAL MALFUNCTION THRESHOLDS
| Parameter | Standard value |
|---|---|
| In the normal condition, the heated oxygen sensor voltage | 0 to 1 V |
COMPONENT OPERATING RANGE
| Parameter | Standard value |
|---|---|
| Voltage output from heated oxygen sensor | Quickly fluctuates between 0.4 and 0.55 V |
COMPONENT OPERATING RANGE
| Detection Criteria | Threshold |
|---|---|
| Front heated oxygen sensor voltage | 0.45 V or more |
TYPICAL MALFUNCTION THRESHOLDS
| Parameter | Standard value |
|---|---|
| In the normal condition, the front heated oxygen sensor voltage | 0 to 1 V |
COMPONENT OPERATING RANGE
| Parameter | Standard Value |
|---|---|
| Heated oxygen sensor voltage | 0 to 1 V |
COMPONENT OPERATING RANGE
| Detection Criteria | Threshold |
|---|---|
| Following condition is continue for 3 sec. | A or B |
| A. Smoothed fuel trim learning value (Lean) | 40% or more |
| B. Smoothed fuel trim learning value (Rich) | 35% or less |
TYPICAL MALFUNCTION THRESHOLDS