DESCRIPTION
This DTC is stored when the engine does not start even though the STA signal is input or when the engine takes a long time to start, and when the engine speed is low or the engine stalls just after the engine starts.
Using the Techstream, the conditions present when the DTC was stored can be confirmed by referring to the freeze frame data. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.
It is necessary to check if the vehicle ran out of fuel before performing troubleshooting, as this DTC is also stored when there is engine starting trouble due to running out of fuel.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P1604 | Either condition is met: The engine speed is less than 500 RPM with the STA signal on for a certain amount of time (refer to the illustration below) (1 trip detection logic). After the engine starts (engine speed is 500 RPM or more), the engine speed drops to 200 RPM or less within approximately 2 seconds (1 trip detection logic). | Immobiliser system Engine assembly (excess friction, compression loss) Starter Crankshaft position sensor Engine coolant temperature sensor Fuel pump Fuel pump control system Fuel pipes Fuel injector assembly Throttle body with motor assembly Pressure regulator Battery Drive plate Spark plug Ignition coil circuit Intake system Camshaft timing oil control valve assembly Mass air flow meter Air fuel ratio sensor Valve timing Fuel Purge VSV Intake valve Exhaust valve ECM |
Scheme 428
The ECM continuously monitors its main and sub CPUs. This self-check ensures that the ECM is functioning properly. If outputs from the CPUs are different and deviate from the standard, the ECM will illuminate the MIL and store this DTC immediately.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P1607 | ECM CPUs malfunction. | ECM |
Refer to DTC P0412. Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P1613 | Either condition (1) or (2) met: (1) All conditions are met (1 trip detection logic): Either the air pump or the air switching valve is not operating. Diagnostic signal from the air injection control driver is 80%. Battery voltage is 8 V or higher. (2) Both conditions are met (1 trip detection logic): Battery voltage is 8 V or higher. Diagnostic signal from the air injection control driver is abnormal (duty signal other than 0, 20, 40, 80 or 100%). | Air injection control driver Open in air injection control driver ground circuit |
| P1613 | All conditions are met (1 trip detection logic): Air injection system operating (air switching valve and air pump are on). Diagnostic signal from the air injection control driver is 0%. Battery voltage is 8 V or higher. | Open in air pump or air switching valve command signal circuit (ECM - air injection control driver) Open in air injection control driver ground circuit Short between diagnostic signal circuit and body ground Air injection control driver ECM |
| P1613 | Both conditions are met (1 trip detection logic): Battery voltage is 8 V or higher. Diagnostic signal from the air injection control is driver 100%. | Open in diagnostic signal circuit Air injection control driver Open in air injection control driver +B circuit (air injection control driver power source) Short between +B and diagnostic signal circuits Short in air pump or air switching valve command signal circuit (ECM - air injection control driver) Open in air injection control driver ground circuit |
MONITOR DESCRIPTION
For a short time after a cold engine start, the ECM transmits command signals to the air injection control driver to drive the air pump and air switching valve. The air injection control driver detects open and short circuits according to the voltages at the air injection control driver terminals connected to the air pump and air switching valve, and the circuit voltage of the air injection control driver power source, and transmits diagnostic information as a signal to the ECM.
If the Secondary Air Injection (AIR) system circuit or the air injection control driver itself malfunctions, the air injection control driver sends a malfunction signal (duty signal) as diagnostic information to the ECM (when the system is normal, a system normal signal is sent). The ECM stores the DTC based on the diagnostic information from the air injection control driver.
Example
- The duty ratio of the diagnostic signal from the air injection control driver is 0 or 100% (remains at 0 V or is the same as battery voltage).
- The duty ratio of the diagnostic signal from the air injection control driver shows an impossible ratio (a ratio other than 0, 20, 40, 80 or 100%).
- The air injection control driver outputs the normal signal (normal duty signal: 80%) while the system is not operating.
The throttle actuator is operated by the ECM and opens and closes the throttle valve using gears.
The opening angle of the throttle valve is detected by the throttle position sensor, which is built into the throttle body. The throttle position sensor provides feedback to the ECM. This feedback allows the ECM to appropriately control the throttle actuator and monitor the throttle opening angle as the ECM responds to driver inputs.
HINT
This ETCS (Electronic Throttle Control System) does not use a throttle cable.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2102 | Both conditions are met for 2.0 seconds (1 trip detection logic): (a) The throttle actuator duty ratio is 80% or more. (b) The throttle actuator current is below 0.5 A. | Open in throttle actuator circuit Throttle body with motor assembly ECM |
| P2103 | Either condition is met (1 trip detection logic): The throttle actuator current is 10 A or higher for 0.1 seconds. The throttle actuator current is 7 A or higher for 0.6 seconds. | Short in throttle actuator circuit Throttle body with motor assembly ECM |
The ECM monitors the electrical current through the electronic actuator, and detects malfunctions and open circuits in the throttle actuator based on this value. If the current is outside the standard range, the ECM determines that there is a malfunction in the throttle actuator. In addition, if the throttle valve does not function properly (for example, if it is stuck on), the ECM determines that there is a malfunction. The ECM then illuminates the MIL and stores a DTC.
Example
When the electrical current is below 0.5 A and the throttle actuator duty ratio exceeds 80%, the ECM interprets this as the current being outside the standard range, and illuminates the MIL and stores DTC P2102.
If the malfunction is not repaired successfully, the DTC is stored when the engine is quickly revved to a high RPM several times after the engine is started and has idled for 5 seconds.
The idling speed is controlled by the Electronic Throttle Control System (ETCS).
The ETCS is comprised of a throttle actuator, which operates the throttle valve, and a throttle position sensor, which detects the opening amount of the throttle valve.
The ECM controls the throttle actuator to adjust the throttle valve opening amount so that the idling speed is maintained at the target idling speed.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2109 | The ISC learned value is approximately 3 times larger than normal even though the actual intake air amount during idling is within the normal range (up to 1.5 times the normal amount) (5 trip detection logic). | Throttle body with motor assembly |
HINT
- The ISC learned value is the calculated intake air amount corresponding to the throttle opening amount necessary to maintain the idling speed.
- This malfunction is only detected once per trip. After it has been detected once, the system will not monitor for the malfunction for the rest of the trip.
- The system uses the throttle body with motor assembly and mass air flow meter to detect this malfunction.
If there are deposits in the throttle valve, a decrease in the ISC flow rate may cause engine stall an unstable idling. Therefore, the necessary ISC flow rate for idling is maintained using the ISC learned value and feedback. The ECM stores this DTC if the ISC learned value approaches its limit. The ECM begins monitoring for the DTC detection conditions when the following preconditions are met: 1) the mass air flow meter is normal; 2) atmospheric pressure is 85 kPa (638 mmHg) or higher; 3) the vehicle has been driven at a speed of 30 km/h (19 mph) or more at least once; and 4) the engine coolant temperature is 45°C (113°F) or less at engine start, the engine is warmed up and conditions for ISC learning are met, or the ignition switch has been turned to ON (include engine running) for 1 hour or more, the engine is warmed up and conditions for ISC learning are met.
The throttle actuator is operated by the ECM, and opens and closes the throttle valve using gears. The opening angle of the throttle valve is detected by the throttle position sensor, which is mounted on the throttle body with motor assembly. The throttle position sensor provides feedback to the ECM so that the ECM can control the throttle actuator (throttle valve) appropriately in response to driver inputs.
HINT
This ETCS (Electronic Throttle Control System) does not use a throttle cable.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2111 | The ECM signals the throttle actuator to close, but the actuator is stuck (1 trip detection logic). | Throttle body with motor assembly |
| P2112 | The ECM signals the throttle actuator to open, but the actuator is stuck (1 trip detection logic). |
The ECM determines that there is a malfunction in the ETCS when the throttle valve remains at a fixed angle despite a high drive current from the ECM. The ECM illuminates the MIL and stores a DTC.
If the malfunction is not repaired successfully, the DTC is stored when the accelerator pedal is fully depressed and released quickly (to fully open and close the throttle valve) after the engine is next started.
The ETCS (Electronic Throttle Control System) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (below 4 V), the ECM determines that there is a malfunction in the ETCS and cuts off the current to the throttle actuator.
When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the throttle actuator is cut. If repairs are made and the system returns to normal, the ECM then allows the current to flow to the throttle actuator so that it can be restarted after the ignition switch is turned off.
HINT
This ETCS does not use a throttle cable.
Scheme 429
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2118 | An open in the ETCS power source (+BM) circuit (1 trip detection logic). | Open in electronic throttle control system power source circuit Battery Battery terminals ETCS fuse ECM |
The ECM monitors the battery supply voltage applied to the throttle actuator.
When the power supply voltage (+BM) drops below 4 V for 0.8 seconds or more, the ECM interprets this as an open in the power supply circuit (+BM). The ECM illuminates the MIL and stores the DTC.
If the malfunction is not repaired successfully, the DTC is stored 5 seconds after the engine is next started.
The Electronic Throttle Control System (ETCS) is composed of the throttle actuator, throttle position sensor, accelerator pedal position sensor and ECM. The ECM operates the throttle actuator to regulate the throttle valve in response to driver inputs. The throttle position sensor detects the opening angle of the throttle valve and provides the ECM with feedback so that the throttle valve can be appropriately controlled by the ECM.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2119 | The throttle valve opening angle continues to vary greatly from the target opening angle (1 trip detection logic). | Electronic throttle control system ECM |
The ECM determines the actual opening angle of the throttle valve from the throttle position sensor signal. The actual opening angle is compared to the target opening angle calculated by the ECM. If the difference between these two values is outside the standard range, the ECM interprets this as a malfunction in the ETCS. The ECM then illuminates the MIL and stores the DTC.
If the malfunction is not repaired successfully, the DTC is stored when the accelerator pedal is quickly released (to close the throttle valve) after the engine speed reaches 5000 RPM by the accelerator pedal being fully depressed (fully opening the throttle valve).
The accelerator pedal sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type. It uses Hall-effect elements in order to yield accurate signals, even in extreme driving conditions, such as at high speeds as well as very low speeds. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal position (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the accelerator pedal sensor itself.
The ECM monitors the actual accelerator pedal position (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.
Scheme 430
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2120 | VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1-trip detection logic). | Accelerator pedal sensor assembly ECM |
| P2122 | VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1-trip detection logic). | Accelerator pedal sensor assembly Open in VCPA circuit Open or ground short in VPA circuit ECM |
| P2123 | VPA is 4.8 V or higher for 2.0 seconds or more (1-trip detection logic). | Accelerator pedal sensor assembly Open in EPA circuit ECM |
| P2125 | VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1-trip detection logic). | Accelerator pedal sensor assembly ECM |
| P2127 | VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1-trip detection logic). | Accelerator pedal sensor assembly Open in VCP2 circuit Open or ground short in VPA2 circuit ECM |
| P2128 | Conditions (a) and (b) are met for 2.0 seconds or more (1-trip detection logic): (a) VPA2 is 4.8 V or higher. (b) VPA is between 0.4 V and 3.45 V. | Accelerator pedal sensor assembly Open in EPA2 circuit ECM |
| P2138 | Condition (a) or (b) is met for 2.0 seconds or more (1-trip detection logic): (a) The difference between VPA and VPA2 is 0.02 V or less. (b) VPA is 0.4 V or less and VPA2 is 1.2 V or less. | Short between VPA and VPA2 circuits Accelerator pedal sensor assembly ECM |
HINT
When any of these DTCs are output, check the accelerator pedal position sensor voltage using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.
| Trouble Area | Accel Sensor Out No. 1 When Accelerator Pedal Released | Accel Sensor Out No. 2 When Accelerator Pedal Released | Accel Sensor Out No. 1 When Accelerator Pedal Depressed | Accel Sensor Out No. 2 When Accelerator Pedal Depressed |
|---|---|---|---|---|
| VCPA or VCP2 circuit open | 0 to 0.2 V | 0 to 0.2 V | 0 to 0.2 V | 0 to 0.2 V |
| Open or ground short in VPA circuit | 0 to 0.2 V | 1.2 to 2.0 V | 0 to 0.2 V | 3.4 to 5.0 V |
| Open or ground short in VPA2 circuit | 0.5 to 1.1 V | 0 to 0.2 V | 2.6 to 4.5 V | 0 to 0.2 V |
| EPA or EPA2 circuit open | 4.5 to 5.0 V | 4.5 to 5.0 V | 4.5 to 5.0 V | 4.5 to 5.0 V |
| Normal condition | 0.5 to 1.1 V | 1.2 to 2.0 V | 2.6 to 4.5 V | 3.4 to 5.0 V |
HINT
Accelerator pedal positions are expressed as voltages.
When the output voltage of either VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the accelerator pedal position sensor. The ECM then illuminates the MIL and stores a DTC.
Example
When the output voltage of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is stored.
If the malfunction is not repaired successfully, the DTC is stored 2 seconds after the engine is next started.
HINT
Refer to DTC P2120. Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2121 | The difference between VPA and VPA2 is less than 0.4 V, or more than 1.2 V for 0.5 seconds (1-trip detection logic). | Accelerator pedal sensor assembly ECM |
When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal sensor assembly is malfunctioning. The ECM turns on the MIL and stores the DTC.
HINT
- Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
- Sensor 1 refers to the sensor mounted in front of the three way catalytic converter and located near the engine assembly.
The air fuel ratio sensor generates a voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio and regulates the fuel injection time. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.
The air fuel ratio sensor is of the planar type and is integrated with a heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows through the heater to heat the sensor in order to facilitate accurate air fuel ratio detection. The heat generated by the heater is conducted to the solid electrolyte through the alumina, thereby accelerating the sensor activation.
A three way catalytic converter is used in order to convert the carbon monoxide, hydrocarbons and nitrogen oxide into less harmful substances. To allow the three way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.
*: The value changes inside the ECM. Since the air fuel ratio sensor is a current output element, current is converted into a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.
Scheme 431
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2195 | Conditions (a) and (b) are met for 5 seconds or more (2 trip detection logic): (a) The air fuel ratio sensor voltage is higher than 3.8 V. (b) Heated oxygen sensor voltage is 0.21 V or higher. | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor heater and relay circuits Intake system Fuel pressure Fuel Injector assembly ECM |
| While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is 3.6 mA or higher (2 trip detection logic). | Air fuel ratio sensor ECM | |
| P2196 | Conditions (a) and (b) are met for 5 seconds or more (2 trip detection logic): (a) The air fuel ratio sensor voltage is below 2.8 V for 10 seconds. (b) Heated oxygen sensor voltage is below 0.59 V. | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor heater and relay circuits Intake system Fuel pressure Fuel Injector assembly ECM |
| While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is below 1 mA (2 trip detection logic). | Air fuel ratio sensor ECM |
HINT
- When either of these DTCs is stored, check the air fuel ratio sensor output voltage using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM maintains the voltages at the A1A+ and A1A- terminals of the ECM at a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the Techstream.
- If the air fuel ratio sensor is malfunctioning, the ECM stores DTC P2195 or P2196.
Scheme 432
- Sensor voltage detection monitor Under air-fuel ratio feedback control, if the air fuel ratio sensor output voltage indicates a rich or lean air fuel ratio for a certain period of time, the ECM determines that there is a malfunction in the air fuel ratio sensor. The ECM illuminates the MIL and stores a DTC. Example: If the air fuel ratio sensor output voltage is below 2.8 V (a very rich condition) for 5 seconds despite the rear heated oxygen sensor output voltage being below 0.59 V, the ECM stores DTC P2196. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (a very lean condition) for 5 seconds despite the rear heated oxygen sensor output voltage being 0.21 V or higher, DTC P2195 is stored.
- Sensor current detection monitor A rich air-fuel mixture causes a low air fuel ratio sensor current, and a lean air-fuel mixture causes a high air fuel ratio sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the air fuel ratio sensor current during fuel-cut and detects any abnormal current values. If the air fuel ratio sensor output is 3.6 mA or higher for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the air fuel ratio sensor and stores DTC P2195 (stuck on high side). If the air fuel ratio sensor output is 1.0 mA or less for more than 3 seconds of cumulative time, the ECM stores DTC P2196 (stuck on low side).
Refer to DTC P2195. Refer to DESCRIPTION.
HINT
- Although the DTC titles refer to the oxygen sensor, these DTCs relate to the air fuel ratio sensor.
- Sensor 1 refers to the sensor mounted in front of the three way catalytic converter and located near the engine assembly.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2237 | An open in the circuit between terminals A1A+ and A1A- of the air fuel ratio sensor while the engine is running (2 trip detection logic). | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM |
| P2238 | Case 1: Condition (a) or (b) is met for 5.0 seconds or more (2 trip detection logic): (a) AF+ voltage is 0.5 V or less. (b) (AF+) - (AF-) is 0.1 V or less. Case 2: Air fuel ratio sensor admittance is below 0.022 1/ohms (2 trip detection logic). | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM |
| P2239 | The A1A+ voltage is higher than 4.5 V (2 trip detection logic). | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM |
| P2252 | The A1A- voltage is 0.5 V or less (2 trip detection logic). | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM |
| P2253 | A1A- voltage is higher than 4.5 V (2 trip detection logic). | Open or short in air fuel ratio sensor circuit Air fuel ratio sensor ECM |
The air fuel ratio sensor varies its output voltage in proportion to the air-fuel ratio. If the air fuel ratio sensor impedance (alternating current resistance) or output voltage deviates greatly from the standard range, the ECM determines that there is an open or short in the air fuel ratio sensor circuit.
The description can be found in EVAP (Evaporative Emission) System. Refer to DESCRIPTION.
5 hours* after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.
HINT
*: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.
| Sequence | Operation | Description | Duration |
|---|---|---|---|
| ECM activation | Activated by soak timer 5, 7 or 9.5 hours after ignition switch turned off. | ||
| A | Atmospheric pressure measurement | Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure. If pressure in EVAP system not between 70 kPa-a and 110 kPa-a (525 mmHg-a and 825 mmHg-a), ECM cancels EVAP system monitor. | 60 seconds |
| B | First reference pressure measurement | In order to determine reference pressure, leak detection pump creates negative pressure (vacuum) through reference orifice and then ECM checks if leak detection pump and vent valve operate normally. | 360 seconds |
| C | EVAP system pressure measurement | Vent valve turned ON (closed) to shut EVAP system. Negative pressure (vacuum) created in EVAP system, and EVAP system pressure then measured. Write down measured value as it will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. | 15 minutes* |
| D | Purge VSV monitor | Purge VSV opened and then EVAP system pressure measured by ECM. Large increase indicates normality. | 10 seconds |
| E | Second reference pressure measurement | After second reference pressure measurement, leak check performed by comparing first and second reference pressure. If stabilized system pressure higher than second reference pressure, ECM determines that EVAP system leaking. | 60 seconds |
| Final check | Atmospheric pressure measured and then monitoring result recorded by ECM. |
*: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
Scheme 433
P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closes) and the EVAP system pressure is then measured by the ECM using the canister pressure sensor to conduct an EVAP leak check. If the pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and stores the DTC.
Scheme 434
The Secondary Air injection (AIR) system consists of an air pump, the air switching valve, a pressure sensor, the air injection control driver and the ECM. For a short time after cold engine starts, the AIR system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The secondary air is supplied by the air pump and is pumped to the exhaust port through the air switching valve.
The air injection control driver drives the air switching valve and air pump according to command signals transmitted by the ECM. The pressure sensor detects the pressure in the secondary air passage when the AIR system is on and off, and transmits a pressure signal to the ECM.
The air injection control driver is not only equipped to drive the pump and valve, but also has a diagnosis function to detect malfunctions in the AIR system circuit.
HINT
As a large current is required to drive the air pump and air switching valve, an air injection control driver is included in this system.
Scheme 435
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2431 | Pressure sensor indicates a value below 45 kPa (338 mmHg), or higher than 135 kPa (1,013 mmHg) (2 trip detection logic). | Air pressure sensor Open or short in air pressure sensor circuit ECM |
| P2432 | While the engine is running, the voltage output of the pressure sensor is below 0.1 V (1 trip detection logic). | Air pressure sensor Open or short in air pressure sensor circuit ECM |
| P2433 | While the engine is running, the voltage output of the pressure sensor is higher than 4.8 V (1 trip detection logic). | Air pressure sensor Open or short in air pressure sensor circuit ECM |
Scheme 436
The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system.
If there is a defect in the sensor or sensor circuit, the voltage level deviates from the normal operating range and the ECM interprets this deviation as a malfunction in the pressure sensor or circuit and stores a DTC.
Refer to DTC P0412. Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2440 | Pressure sensor detects pulsation of exhaust gas despite the ECM commanding the air switching valve to close while the engine is running (2 trip detection logic). | Air switching valve assembly Open or short in air switching valve circuit Pressure sensor Pressure sensor circuit Air injection control driver ECM |
| P2441 | Pressure sensor detects no pulsation of exhaust gas despite the ECM commanding the air switching valve to open while the engine is running (2 trip detection logic). | Air switching valve assembly Open or short in air switching valve circuit Vacuum hose (air switching valve - pressure sensor) Air injection hose Pressure sensor Pressure sensor circuit Air injection control driver ECM |
HINT
Air switching valve normal operation
When the air switching valve is open, exhaust gas pulsation occurs in the secondary air passage.
When the air switching valve is closed, exhaust gas pulsation does not occur in the secondary air passage.
The ECM monitors the pressure in the secondary air passage using the pressure sensor connected to the air switching valve of the Secondary Air Injection (AIR) system.
If either of the following conditions occurs, the ECM interprets it as a malfunction of the secondary AIR system, and illuminates the MIL and stores a DTC
- Exhaust gas pulsation is detected by the pressure sensor despite the ECM commanding the air switching valve to close.
- Exhaust gas pulsation is not detected by the pressure sensor despite the ECM commanding the air switching valve to open.
Refer to P2440. Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2444 | Secondary air pressure is higher than 2.5 kPa (19 mmHg) despite the ECM commanding the air pump to turn off (2 trip detection logic). | Short in air pump circuit Open or short in pressure sensor circuit Pressure sensor Air injection control driver ECM |
| P2445 | Secondary air pressure is below 2.5 kPa (19 mmHg) despite the ECM commanding the air pump to turn on (2 trip detection logic). | Air pump Open in air pump circuit Air injection system piping Vacuum hose (pressure sensor - air switching valve) Pressure sensor Open or short in pressure sensor circuit Air injection control driver ECM |
The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the air switching valve of the Secondary Air Injection (AIR) system. The sensor measures the pressure in the secondary air passage and transmits a signal to the ECM.
If either of the following conditions occurs, the ECM interprets it as a malfunction of the AIR system, and illuminates the MIL and stores a DTC
- The pressure indicated by the pressure sensor does not reach threshold levels despite the ECM turning on the air pump.
- The pressure indicated by the pressure sensor exceeds threshold levels despite the ECM turning off the air pump.
The soak timer operates after the ignition switch is turned off. When a certain amount of time has elapsed after turning the ignition switch off, the soak timer activates the ECM to perform malfunction checks which can only be performed after the engine is stopped. The soak timer is built into the ECM.
Scheme 437
- While the engine is running, the ECM monitors the synchronization of the soak timer and CPU clock. If these two are not synchronized, the ECM interprets this as a malfunction, illuminates the MIL and stores the DTC.
- If the soak timer activates the ECM even though only a short amount of time has elapsed since the ignition switch was turned off, or if the soak timer does not activate the ECM even though a considerable amount of time has elapsed since the ignition switch was turned off, the ECM determines that the soak timer is malfunctioning, illuminates the MIL and stores a DTC the next time the ignition switch is turned to ON.
Refer to DTC P2195. Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2A00 | Calculated value of the air fuel ratio sensor response rate deterioration level is less than the threshold (2 trip detection logic). | Air fuel ratio sensor Air fuel ratio sensor heater Fuel injector Fuel pump Fuel line ECM |
After the engine is warmed up, the ECM performs air-fuel ratio feedback control to maintain the air-fuel ratio at the stoichiometric level. In addition, active A/F control is performed for approximately 10 seconds after the preconditions are met in order to measure the air fuel ratio sensor response rate. During active A/F control, the ECM forcibly increases and decreases the injection volume a certain amount based on the stoichiometric air-fuel ratio learned during normal air-fuel ratio control, and measures the air fuel ratio sensor response rate. The ECM receives a signal from the air fuel ratio sensor while performing active A/F control and uses it to calculate the air fuel ratio sensor response rate deterioration level.
If the air fuel ratio sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores the DTC.
Scheme 438
When the ignition switch is turned to ON, battery voltage is applied to terminal IGSW of the ECM. The output signal from the MREL terminal of the ECM causes current to flow to the coil, closing the contacts of the integration relay (EFI MAIN relay) and supplying power to terminal +B of the ECM.
Scheme 439
The ECM constantly generates a 5 V power supply voltage from the battery voltage supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power source voltage to the sensors through the VC output circuit.
Scheme 440
When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.
HINT
Under normal conditions, the MIL is illuminated for several seconds when the ignition switch is first turned to ON, and then goes off when the engine starts.
Scheme 441
The fuel pump circuit consists of the ECM, fuel pump and fuel pump ECU (which operates the fuel pump). Based on the engine output, the ECM determines the fuel pump speed. The speed is then converted to a duty signal and sent to the fuel pump ECU. Based on the signal sent from the ECM, the fuel pump ECU adjusts the fuel pump operation speed between 3 settings.
The fuel injectors are located on the intake manifold. They inject fuel into the cylinders based on the signals from the ECM.
While the engine is being cranked, current flows from terminal ST1 of the ignition switch to the park/neutral position switch (for automatic transmission) and also flows to terminal STA of the ECM (STA Signal).
When the vehicle is being driven with the accelerator pedal depressed, depressing the brake pedal without releasing the accelerator pedal will activate the brake override system to restrict driving torque. The conditions for activating the brake override system as well as the items that are controlled are explained below.
Scheme 442
Activation Conditions
- Vehicle is running at or above the specified speed.
- The accelerator pedal is depressed beyond a specified level, and then the brake pedal is depressed.
Note. The vehicle may not enter the brake override system control due to the relation of the accelerator pedal angle and the vehicle's speed.
Items Controlled
- Driving torque is restricted.
HINT
During brake override system control, the value for the accelerator pedal angle (which is used for engine control) is forcibly reduced to a specified value. For this reason, the Data List value for Accelerator Position (applied to electronic throttle control) will be replaced with a specified value regardless of the actual accelerator pedal angle (Accel Sens. No. 1 Volt %, Accel Sens. No. 2 Volt %)
Deactivation Conditions
- When the Stop Light Switch turns OFF or the actual accelerator pedal angle increases or decreases beyond the specified range.
The MIL (Malfunction Indicator Lamp) is used to indicate the detection of vehicle malfunctions by the ECM. When the ignition switch is turned to ON, power is supplied to the MIL circuit and the ECM provides the circuit ground which illuminates the MIL.
The MIL operation can be checked visually; when the ignition switch is first turned to ON, the MIL turns on and then off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.
