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 of the following conditions is met (1 trip detection logic): The engine speed is below 500 rpm with the STA signal on for a certain amount of time (refer to the illustration below). After the engine starts (engine speed is 500 rpm or higher), the engine speed drops to 200 rpm or less within approximately 2 seconds. | Engine assembly (excess friction, compression loss) Starter assembly Crankshaft position sensor Camshaft position sensor Engine coolant temperature sensor Fuel pump Fuel pump control system Fuel line (fuel filter, pipes and hoses) Fuel injector assembly Throttle with motor body assembly Fuel pressure regulator Battery Drive plate and ring gear sub-assembly Spark plug Ignition coil assembly circuit Intake system Camshaft timing oil control valve assembly Mass air flow meter sub-assembly Air fuel ratio sensor Valve timing Fuel Purge VSV Intake valve Engine immobiliser system ECM |
Scheme 100
MONITOR DESCRIPTION
The ECM continuously monitors its main and sub CPUs while cruise control is operating. This self-check ensures that the ECM is functioning properly. If outputs from the CPUs are different and deviate from the standard, the ECM illuminates the MIL and stores the DTC immediately.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P1607 | An ECM internal error. | ECM |
The Tumble Control Valve (TCV) is built into the intake manifold. The TCV is composed of a position sensor and a DC motor. The DC motor opens and closes the TCV in response to signals from the ECM. The position sensor detects the opening angle of the TCV.
When the TCV is closed, the intake air tumble flow intensifies and negative pressure is generated between the tumble control valve and intake valve which atomizes the fuel. Combustion is enhanced and exhaust gas emissions are reduced at low temperatures.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2004 (Stuck open) | When the TCV opening angle is 17° or more after requesting the TCV to fully close (2 trip detection logic). | DC Motor for TCV circuit DC Motor for TCV TCV position sensor TCV ECM |
| P2006 (Stuck closed) | When the TCV opening angle is less than 35° after requesting the TCV to fully open (2 trip detection logic). | Same as DTC No. P2004 |
HINT
After confirming DTCs P2004 and/or P2006, use the Techstream to confirm the Intake Air Control Position while performing Control the IAC Duty Ratio of the Active Test.
| Control the IAC Duty Ratio operation | Intake Air Control Position |
|---|---|
| 100% | 70° |
| 0% | 70° |
| 100% | 2° |
REFERENCE (NORMAL CONDITION)
| Coolant Temperature and Intake Air Temperature at Engine Start | Intake Air Control Position |
|---|---|
| 10°C or less | 70° |
| 60°C or higher | 70° |
| 10 to 60°C | 2° |
REFERENCE (NORMAL CONDITION)
When the ECM has requested a TCV close operation but the actual TCV opening angle is 17° or more for 10 seconds, DTC P2004 is output. When the ECM has requested a TCV open operation but the actual TCV opening angle is less than 35° for 10 seconds, DTC P2006 is output.
The ECM activates the DC motor for the Tumble Control Valve (TCV), which opens and closes the TCV. The ECM activates the DC motor based on engine speed, coolant temperature, intake air temperature and other conditions.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2009 | Both of the following conditions continue for 1 second (1 trip detection logic): (a) The output duty of the DC motor for the TCV is 100%. (b) The current of the DC motor for the TCV is below 0.35 A. | Open or short in DC motor for TCV circuit Intake manifold (DC motor for TCV) ECM |
| P2010 | Either of the following conditions continues for 0.2 seconds or more (1 trip detection logic): (a) The motor drive IC is overcurrent. (b) The motor drive IC overheats. | Open or short in DC motor for TCV circuit Intake manifold (DC motor for TCV) ECM |
When the voltage of the DC motor deviates from the standard range, the ECM determines that a malfunction has occurred and outputs a DTC.
The Tumble Control Valve (TCV) position sensor is a non-contact type sensor.
The position sensor measures the opening angle of the TCV. The sensor is reliable and accurate, as it is electrically controlled by Hall elements.
Scheme 101
| DTC No. | DTC Detection Connection | Trouble Area |
|---|---|---|
| P2014 | The TCV position sensor output voltage flutters up and down beyond the normal operating range (below 0.2 V or higher than 4.8 V) for more than 0.5 seconds (open or short) (1 trip detection logic). | Open or short in TCV position sensor circuit TCV position sensor ECM |
| P2016 | The TCV position sensor output voltage is below 0.2 V for more than 0.5 seconds (short) (1 trip detection logic). | Same as DTC No. P2014 |
| P2017 | The TCV position sensor output voltage is higher than 4.8 V for more than 0.5 seconds (open) (1 trip detection logic). | Same as DTC No. P2014 |
HINT
After confirming DTC P2014, P2016 or P2017, use the Techstream to confirm the IAC Sensor Voltage (TCV position sensor output voltage). Enter the following menus: Powertrain / Engine and ECT / Data List / All Data.
| IAC Sensor Voltage | Malfunction |
|---|---|
| 0.2 V or less | IAC1 circuit shorted VCIA circuit open |
| 4.8 V or higher | VCIA and IAC1 circuit short-circuited IAC1 circuit open EIA1 circuit open |
The ECM IAC1 terminal voltage increases in correlation with the opening angle of the TCV. When the TCV is fully closed, approximately 0.8 V is applied to the IAC1 terminal. When the TCV is fully open, approximately 3.6 V is applied to the IAC1 terminal.
When the output voltage of the IAC1 terminal deviates from the standard range, the ECM determines that a malfunction has occurred in the position sensor and stores a DTC. Refer to ECM Power Source Circuit.Refer to ECM Power Source Circuit.
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 (TP) sensor, which is mounted on the throttle body. The TP 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 of the following conditions continue 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 actuator ECM |
| P2103 | Either of the following conditions is met (1 trip detection logic): A hybrid IC diagnosis signal failure. A hybrid IC current limiter port failure. | Short in throttle actuator circuit Throttle actuator Throttle valve Throttle body 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, 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, illuminates the MIL and stores a DTC. If the malfunction is not repaired successfully, a DTC is stored when the engine is quickly revved to a high rpm several times after the engine has idled for 5 seconds after engine start.
The idle 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 idle speed is maintained at the target idle 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 assembly |
HINT
- The ISC learned value is the calculated intake air amount corresponding to the throttle opening amount necessary to maintain the idle 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 with motor body assembly and mass air flow meter sub-assembly to detect this malfunction.
If there are deposits in the throttle valve, a decrease in the ISC flow rate may cause engine stall or 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 sub-assembly is normal.
- 2) Atmospheric pressure is 85 kPa-a [638 mmHg-a] or higher.
- 3) The vehicle has been driven at a speed of 30 km/h (18.6 mph) or more at least once.
- 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 (TP) sensor, which is mounted on the throttle body. The TP 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 |
|---|---|---|
| P2111 | The ECM signals the throttle actuator to close, but the actuator is stuck (1 trip detection logic). | Throttle actuator Throttle body Throttle valve ECM |
| P2112 | The ECM signals the throttle actuator to open, but the actuator is stuck (1 trip detection logic). | Throttle actuator Throttle body Throttle valve ECM |
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, a 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, turn the ignition switch off. The ECM then allows the current to flow to the throttle actuator so that it can be restarted.
HINT
The ETCS does not use a throttle cable.
Scheme 102
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2118 | An open in the ETCS power source (+BM) circuit (1 trip detection logic). | Open in ETCS 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 (TP) sensor, Accelerator Pedal Position (APP) sensor, and ECM. The ECM operates the throttle actuator to regulate the throttle valve in response to driver inputs. The TP 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 (ETCS) ECM |
The ECM determines the actual opening angle of the throttle valve from the TP sensor signal. The actual opening angle is compared to the target opening angle commanded 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 fully depressing the accelerator pedal (fully open the throttle valve).
HINT
- This ETCS (Electronic Throttle Control System) does not use a throttle cable.
- These DTCs relate to the Accelerator Pedal Position (APP) sensor.
The Accelerator Pedal Position (APP) 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 sensor and 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 0.5 V and 4.5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (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 APP sensor itself.
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.
Scheme 103
| 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 Position (APP) sensor ECM |
| P2122 | VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic). | Accelerator Pedal Position (APP) sensor Open in VCP1 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 Position (APP) sensor 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 Position (APP) sensor ECM |
| P2127 | VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is depressed (1 trip detection logic). | Accelerator Pedal Position (APP) sensor Open in VCP2 circuit Open or ground short in VPA2 circuit ECM |
| P2128 | Both of the following conditions continue 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 Position (APP) sensor Open in EPA2 circuit ECM |
| P2138 | Either of the following conditions continues 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 Position (APP) sensor ECM |
HINT
When any of these DTCs are output, check the APP sensor voltage using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / 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 |
|---|---|---|---|---|
| VCP 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 4.98 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 circuit open | 4.5 to 4.98 V | 4.5 to 4.98 V | 4.5 to 4.98 V | 4.5 to 4.98 V |
| Normal condition | 0.5 to 1.1 V | 1.2 to 2.0 V | 2.6 to 4.5 V | 3.4 to 4.98 V |
HINT
Accelerator pedal positions are expressed as voltages.
When either output voltage of 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 APP 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, a DTC is stored 2 seconds after the engine is next started.
HINT
- This DTC relates to the Accelerator Pedal Position (APP) sensor.
Refer to DTC P2120.Refer to DESCRIPTION.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2121 | Either of following conditions 1 or 2 met for 0.5 seconds (1 trip detection logic) 1. Difference between VPA and VPA2 is less than 0.4 V, or more than 1.2 V. (learned value of accelerator off position) 2. Difference between VPA and VPA2 is greater than or equal to the specified value. | Accelerator Pedal Position (APP) sensor ECM |
The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal position sensor is malfunctioning. The ECM turns on the MIL and the DTC is stored.
HINT
- Although the DTC titles say oxygen sensor, these DTCs relate to the Air Fuel Ratio (A/F) sensor.
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
The A/F 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 level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.
The A/F sensor is planar-type sensor and is integrated with the 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 into the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are a narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, and therefore the sensor activation is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air-fuel ratio is precisely controlled so that it is always close to the stoichiometric level.
*: The value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted into a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors show a constant voltage.
Scheme 104
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2195 | Both of the following conditions continue for 5 seconds or more (2 trip detection logic): (a) The Air Fuel Ratio (A/F) sensor voltage is higher than 3.8 V. (b) The Heated Oxygen (HO2) sensor voltage is 0.21 V or higher. | Open or short in A/F sensor (sensor 1) circuit A/F sensor (sensor 1) A/F sensor (sensor 1) heater A/F sensor heater circuit Air induction system Fuel pressure Fuel injector ECM |
| While fuel-cut operation is performed (during vehicle deceleration), the Air Fuel Ratio (A/F) sensor current is 3.6 mA or higher for 3 seconds (2 trip detection logic). | A/F sensor ECM | |
| P2196 | Both of the following conditions continue for 5 seconds or more (2 trip detection logic): (a) The Air Fuel Ratio (A/F) sensor voltage is below 2.8 V. (b) The Heated Oxygen (HO2) sensor voltage is below 0.59 V. | Open or short in A/F sensor (sensor 1) circuit A/F sensor (sensor 1) A/F sensor (sensor 1) heater A/F sensor heater circuit Air induction system Fuel pressure Fuel injector ECM |
| While fuel-cut operation is performed (during vehicle deceleration), the Air Fuel Ratio (A/F) sensor current is below 1.0 mA for 3 seconds (2 trip detection logic). | A/F sensor ECM |
HINT
- When any of these DTCs are output, check the A/F sensor voltage output using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Voltage B1 S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+ and A1A- terminals of the ECM to a constant level. Therefore, the A/F sensor voltage output cannot be confirmed without using the Techstream.
- If an A/F sensor malfunction is detected, the ECM stores a DTC.
Sensor voltage detection monitor
Under the air-fuel ratio feedback control, if the Air Fuel Ratio (A/F) sensor voltage output indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL and stores a DTC.
Example
If the A/F sensor voltage output is below 2.8 V (very rich condition) for 5 seconds, despite the HO2 sensor voltage output being below 0.59 V, the ECM stores DTC P2196. Alternatively, if the A/F sensor voltage output is higher than 3.8 V (very lean condition) for 5 seconds, despite the HO2 sensor voltage output being 0.21 V or higher, DTC P2195 is stored.
Sensor current detection monitor
A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F 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 A/F sensor current during fuel-cut and detects any abnormal current values.
If the A/F 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 A/F sensor and stores DTC P2195 (stuck on high side). If the A/F sensor output is below 1.0 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 (stuck on low side).
Scheme 105
HINT
- Although the DTC titles say oxygen sensor, these DTCs relate to the Air Fuel Ratio (A/F) sensor.
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
The A/F sensor, which is located between the exhaust manifold and catalyst, consists of alloyed metal elements and a heater.
Depending on the engine operating conditions, the heater heats the sensor elements to activate them. Battery voltage is applied to the heater, and the sensor ground is controlled by the ECM using a duty ratio.
The sensor elements convert the oxygen concentration in the exhaust gas into voltage values to output. Based on the voltage, the ECM determines the air-fuel ratio and regulates the fuel injection volume depending on the air-fuel ratio and engine operating conditions. The voltage changes between 0.6 V and 4.5 V while the engine is running. If the air-fuel ratio is lean, which means that the oxygen concentration in the exhaust gas is high, the voltage is high. If the air-fuel ratio is rich, which means that the oxygen concentration in the exhaust gas is low, the voltage is low.
Scheme 106
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2237 | An open in the circuit between terminals A1A+ and A1A- of the Air Fuel Ratio (A/F) sensor while the engine is running (2 trip detection logic). | Open in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor (sensor 1) ECM |
| P2238 | One of the following conditions is met (2 trip detection logic): The Air Fuel Ratio (A/F) sensor output drops while the engine is running. The voltage at terminal A1A+ is 0.5 V or less. The voltage difference between terminals A1A+ and A1A- is 0.1 V or less. | Open or short in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor (sensor 1) ECM |
| P2239 | The A1A+ voltage is higher than 4.5 V (2 trip detection logic). | Open or short in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor (sensor 1) ECM |
| P2252 | The A1A- voltage is 0.5 V or less (2 trip detection logic). | Open or short in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor (sensor 1) ECM |
| P2253 | The A1A- voltage is higher than 4.5 V (2 trip detection logic). | Open or short in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor (sensor 1) ECM |
These DTCs are output when there is an open or short in the Air Fuel Ratio (A/F) sensor circuit, or if the A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turning the ignition switch to ON, and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the A/F sensor is between 0.6 V and 4.5 V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM determines that there is a malfunction in the A/F sensor. If the same malfunction is detected in next driving cycle, the MIL is illuminated and a DTC is stored.
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. | 60 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 107
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 108
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 109
- While the engine is running, the ECM monitors the synchronization of the soak timer and the 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 ON.
HINT
- Refer to DTC P2195.Refer to «DESCRIPTION»(ref-493439-S05701506132012081000000).
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2A00 | The calculated value for the Air Fuel Ratio (A/F) sensor response rate deterioration level is less than the threshold. | Open or short in Air Fuel Ratio (A/F) sensor (sensor 1) circuit A/F sensor A/F sensor heater 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 preconditions are met in order to measure the Air Fuel Ratio (A/F) 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 A/F sensor response rate. The ECM receives a signal from the A/F sensor while performing active A/F control and uses it to calculate the A/F sensor response rate deterioration level.
If the value for the A/F sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores the DTC.
Scheme 110
When the ignition switch is turned to ON, battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the integration relay (EFI MAIN relay) and supplying power to either terminal +B or +B2 of the ECM.
Scheme 111
The ECM constantly generates 5 V of power from battery voltage supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.
Scheme 112
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. The MIL turns off when the engine is started.
When the engine is cranked, the starter relay drive signal output from the STAR terminal of the ECM is input into the STA terminal of the ECM, and the NE signal generated by the crankshaft position sensor is also input into the NE+ terminal. The ECM interprets that the engine is cranked, and turns transistor Tr1 in the ECM internal circuit on. The current flows to the C/OPN (Circuit Opening) relay by turning Tr1 on. Then, the fuel pump operates.
While the NE signal is input into the ECM, when the engine is running, the ECM turns Tr1 on continuously.
Scheme 113
Scheme 114
The fuel injectors are located on the intake manifold. They inject fuel into the cylinders based on the signals from the ECM.
Scheme 115
The cranking holding control system continues energizing the ST relay after the ECM detects the starter signal (STSW signal) from the main body ECU until the ECM performs a judgment of "engine started". Furthermore, the ECM outputs an accessory cut signal (ACCR signal) to the ACC relay during cranking to prevent flickering of the combination meter, clock, audio system, and other components.
When the ECM detects the STSW signal, the ECM outputs the starter relay drive signal (STAR signal) to the starter relay through the clutch start switch or park/neutral position switch, and then the engine is cranked. The ECM stops outputting the STAR signal when a variety of conditions are met, such as when the NE signal reaches a predetermined value and when the engine speed is stable. Also, the ECM monitors the ST relay operating conditions based on the STA terminal voltage status.
Scheme 116
Scheme 117
This circuit opens and closes the Intake Air Control Valve (IACV) in response to the engine load in order to increase the intake efficiency (ACIS: Acoustic Control Induction System).
Scheme 118
Scheme 119
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 120
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 is forcibly reduced to a specified value. For this reason, the Data List value for Accelerator Position 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 vehicle malfunction detections 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 turns off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.
