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 below 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 VVT sensor Engine coolant temperature sensor Fuel suction with pump and gauge tube assembly Fuel pump control system Fuel pipes Fuel injector assembly Throttle with motor body assembly Battery Drive plate Spark plug Ignition coil circuit Intake system Camshaft timing oil control valve assembly (for intake side of bank 1, 2) Camshaft timing oil control valve assembly (for exhaust side of bank 1, 2) Mass air flow meter Air fuel ratio sensor Valve timing Fuel Purge VSV Intake valve Exhaust valve ECM |
Scheme 449
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Scheme 451
- Reference waveforms showing a normal cold engine start
- Reference waveforms showing a normal warm engine start
- Reference values when there is an air leak in the intake system during starting difficulty FREEZE FRAME DATA P1604 STABILITY MALFUNCTION Parameter -3 -2 -1 0 1 Unit Engine Speed 1625 1042 501 192 129 RPM Calculate Load 43.1 30.5 38.8 93.3 93.3 % Vehicle Load 9.0 16.0 28.2 34.1 29.8 % MAF 6.01 6.67 5.64 2.62 1.54 gm/sec Atmosphere Pressure -1 -1 -1 -1 -1 psi(gauge) Coolant Temp 180 180 180 180 180 F Intake Air 122 120 118 118 118 F Battery Voltage 12.460 12.519 12.187 12.128 12.050 V Throttle Sensor Volt % 17.6 17.6 17.6 17.2 17.2 % Throttle Sensor #2 Volt % 50.1 50.1 50.1 49.8 49.8 % Throttle Sensor Position 0.0 0.0 0.0 0.0 0.0 % Throttle Motor DUTY 17.6 17.6 17.6 17.2 17.2 % Injector (Port) 3770 2465 2907 3245 7608 μs Injection Volum (Cylinder1) 0.000 0.199 0.199 0.199 0.199 ml Fuel Pump/Speed Status ON ON ON ON ON EVAP (Purge) VSV 0.0 0.0 0.0 0.0 0.0 % EVAP Purge Flow 0.0 0.0 0.0 0.0 0.0 % Purge Density Learn Value 0.000 0.000 0.000 0.000 0.000 EVAP Purge VSV OFF OFF OFF OFF OFF Purge Cut VSV Duty 0.0 0.0 0.0 0.0 0.0 % Target Air-Fuel Ratio 0.889 0.913 0.920 0.925 0.833 AF Lambda B1S1 0.998 0.998 0.998 0.998 0.998 AF Lambda B2S1 0.998 0.998 0.998 0.998 0.998 AFS Voltage B1S1 3.298 3.298 3.298 3.298 3.298 V AFS Voltage B2S1 3.298 3.298 3.298 3.298 3.298 V O2S B1S2 0.000 0.000 0.000 0.000 0.000 V O2S B2S2 0.000 0.000 0.000 0.000 0.000 V Short FT #1 0.000 0.000 0.000 0.000 0.000 % Long FT #1 0.000 0.000 0.000 -0.782 0.000 % Total FT #1 0.000 0.000 0.000 0.000 0.000 Short FT #2 0.000 0.000 0.000 0.000 0.000 % Long FT #2 1.562 0.781 0.781 0.781 0.781 % Total FT #2 0.000 0.000 0.000 0.000 0.000 Fuel System Status #1 OLFault OL OL OL OL Fuel System Status #2 OLFault OL OL OL OL IGN Advance 0.0 17.5 13.5 0.0 0.0 deg Knock Feedback Value -3.0 -3.0 -3.0 -3.0 -3.0 CA Knock Correct Learn Value 23.1 23.1 23.1 23.1 23.1 CA VVT Control Status #1 OFF OFF OFF OFF OFF VVT Control Status #2 OFF OFF OFF OFF OFF Starter Signal OFF OFF OFF OFF OFF
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Scheme 456
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 a DTC immediately.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P1607 | ECM CPUs malfunction (1 trip detection logic) | ECM |
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 with motor body assembly. 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 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 seconds (1 trip detection logic): (a) Throttle actuator duty ratio is 80% or more (b) Throttle actuator current is below 0.5 A | Open in throttle actuator circuit Throttle actuator ECM |
| P2103 | Either condition is met (1 trip detection logic): Hybrid IC diagnosis signal fails Hybrid IC current limiter port fails | Short in throttle actuator circuit Throttle actuator Throttle valve Throttle with motor body assembly ECM |
MONITOR DESCRIPTION
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 engine speed several times after the engine has idled for 5 seconds after engine start.
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 with motor body 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 with motor body assembly and mass air flow meter 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
- The mass air flow meter is normal.
- Atmospheric pressure is 85 kPa (637.5 mmHg) or higher.
- The vehicle has been driven at a speed of 30 km/h (18.6 mph) or more at least once.
- 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 with motor body assembly. The throttle position sensor provides feedback to the ECM so that the ECM can control the throttle actuator (throttle valve) approximately in response to driver inputs.
HINT
This 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 with motor body assembly Throttle valve Wire harness or connector ECM |
| P2112 | The ECM signals the throttle actuator to open, but the actuator is stuck (1 trip detection logic) | Throttle actuator Throttle with motor body assembly Throttle valve Wire harness or connector ECM |
The ECM determines that there is a malfunction in the electronic throttle control system when the throttle valve remains at the 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 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 electronic throttle control system and cuts off the current to the throttle actuator.
When the voltage becomes unstable, the electronic throttle control system 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
This electronic throttle control system does not use a throttle cable.
Scheme 457
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2118 | An open in electronic throttle control system 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 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 | Throttle valve opening angle continues to vary greatly from the target opening angle (1 trip detection logic) | Electronic throttle control system Wire harness or connector 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 commanded by the ECM. If the difference between these 2 values is outside the standard range, the ECM interprets this as a malfunction in the electronic throttle control system. 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 depressing the accelerator pedal (fully open the throttle valve).
HINT
- These DTCs relate to the accelerator pedal sensor assembly.
- This electronic throttle control system does not use a throttle cable.
The accelerator pedal sensor assembly 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 conditions. 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 operating 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 accelerator pedal sensor assembly itself.
The ECM monitors the actual accelerator pedal operating angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.
Scheme 458
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2120 | VPA fluctuates rapidly beyond 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 accelerator pedal is depressed (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 more for 2.0 seconds or more (1 trip detection logic) | Accelerator pedal sensor assembly Open in EPA circuit ECM |
| P2125 | VPA2 fluctuates rapidly beyond 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 accelerator pedal is depressed (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) continue for 2.0 seconds or more (1 trip detection logic): (a) VPA2 is 4.8 V or more (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) continues for 2.0 seconds or more (1 trip detection logic): (a) 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 stored, check the accelerator pedal sensor assembly voltage by entering the following menus: Powertrain / Engine / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.
| Trouble Area | Accelerator Sensor Out No. 1 When Accelerator Pedal Released | Accelerator Sensor Out No. 2 When Accelerator Pedal Released | Accelerator Sensor Out No. 1 When Accelerator Pedal Depressed | Accelerator Sensor Out No. 2 When Accelerator Pedal Depressed |
|---|---|---|---|---|
| Open in VCPA or VCP2 circuit | 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 4.8 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 |
| Open in EPA or EPA2 circuit | 4.8 to 5.0 V | 4.8 to 5.0 V | 4.8 to 5.0 V | 4.8 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 4.7 V |
HINT
Accelerator pedal positions are expressed as voltages.
- When either of the output voltages 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 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, a 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 | 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 higher 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 sensor assembly 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 voltage outputs 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 include oxygen sensor, these DTCs relate to the air fuel ratio sensor.
The air fuel ratio sensor generates 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 duration. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.
The air fuel ratio sensor is a planar type and 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 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 three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.
*: Value changes inside the ECM. Since the air fuel ratio sensor is a current output element, the 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 459
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2195 P2197 | Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) 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 (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) 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 2.2 mA or higher for 3 seconds (2 trip detection logic). | Air fuel ratio sensor (bank 1, 2 sensor 1) ECM | |
| P2196 P2198 | Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage is less than 2.8 V. (b) Heated oxygen sensor voltage is less than 0.59 V. | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) 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 less than 0.8 mA for 3 seconds (2 trip detection logic). | Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
HINT
- DTCs P2195 and P2196 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
- DTCs P2197 and P2198 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
- When any of these DTCs is stored, check the air fuel ratio sensor voltage output by entering the following menus on the Techstream: Powertrain / Engine / Data List / AFS Voltage B1S1 or AFS Voltage B2S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the Techstream.
- If an air fuel ratio sensor malfunction is detected, the ECM stores a DTC.
Sensor Voltage Detection Monitor
Under air fuel ratio feedback control, If the air fuel ratio sensor output voltage is less than 2.8 V (very rich condition) for 5 seconds despite the heated oxygen sensor output voltage being less than 0.59 V, the ECM stores DTC P2196 or P2198. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (very lean condition) for 5 seconds despite the heated oxygen sensor output voltage being 0.21 V or higher, DTC P2195 or P2197 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 2.2 mA or more 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 or P2197 (stuck on high side). If the air fuel ratio sensor output is less than 0.8 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 or P2198 (stuck on low side).
Scheme 460
HINT
- Although the DTC titles include 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 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 duration. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.
The air fuel ratio sensor is a planar type with an integrated 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), current flows to the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, and therefore the sensor activation is accelerated.
A three-way catalytic converter is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxides (NOx) 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.
*: Value changes inside the ECM. Since the air fuel ratio sensor uses a current output element, the current is converted to a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.
Scheme 461
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2237 P2240 | Open in the circuit between terminals A1A+ (A2A+) and A1A- (A2A-) of the air fuel ratio sensor while engine running (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2238 P2241 | Case 1: Condition (a) or (b) continues for 5.0 seconds or more(2 trip detection logic):(a) Voltage at terminal A1A+ (A2A+) is 0.5 V or less(b) Voltage difference between terminals A1A+ (A2A+) and A1A- (A2A-) is 0.1 V or less for 10 seconds Case 2: Air fuel ratio sensor admittance: Less than 0.0074 1/ohms(2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2239 P2242 | A1A+ (A2A+) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2252 P2255 | A1A- (A2A-) voltage is 0.5 V or less for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2253 P2256 | A1A- (A2A-) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
HINT
- DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
- DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
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 voltage output 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 (Evaporative Emission) 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 hours (7 or 9.5 hours) after ignition switch is turned off. | ||
| A | Atmospheric pressure measurement | Vent valve is turned off (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure. If pressure in EVAP system is not between 70 kPa(abs) and 110 kPa(abs) [525 mmHg(abs) and 825 mmHg(abs)], ECM cancels EVAP system monitor. | 60 seconds |
| B | First reference pressure measurement | In order to determine reference pressure, vacuum pump creates negative pressure (vacuum) through reference orifice and then ECM checks if vacuum pump and vent valve operate normally. | 360 seconds |
| C | EVAP system pressure measurement | Vent valve is turned on (closed) to shut EVAP system. Negative pressure (vacuum) is created in EVAP system, and then EVAP system pressure is measured. Write down measured value as they 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 is opened and then EVAP system pressure is measured by ECM. Large increase indicates normal. | 10 seconds |
| E | Second reference pressure measurement | After second reference pressure measurement, leak check is performed by comparing first and second reference pressure. If stabilized system pressure is higher than second reference pressure, ECM determines that there is a leak in EVAP system. | 60 seconds |
| Final check | Atmospheric pressure is measured and then monitoring result is 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 462
| *1 | Purge VSV: OFF (closed) | *2 | Purge VSV: ON (open) |
|---|---|---|---|
| *3 | Vent Valve: OFF (vent) | *4 | Vent Valve: ON (closed) |
| *5 | Leak Detection Pump: OFF | *6 | Leak Detection Pump: ON |
| *7 | Reference Orifice (0.02 inch) | *8 | Canister Pressure Sensor |
| *9 | Canister | *10 | Fuel Tank |
| *11 | Canister Pump Module | *12 | Canister Filter |
| *a | Operation A: Atmospheric Pressure Measurement | *b | Operation B, E: Reference Pressure Measurement |
| *c | Operation C: EVAP System Pressure Measurement | *d | Operation D: Purge VSV Monitor |
| *e | Atmospheric Pressure | *f | Negative Pressure |
TEXT IN ILLUSTRATION
P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closed) 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 463
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 464
- 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.
The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter assembly, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and store a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| U0101 | Following conditions are met for 1.25 seconds (1 trip detection logic): Ignition switch ON Battery voltage 10.5 V or more No intercommunication between ECM and TCM | ECM to TCM circuit TCM ECM |
LOCATION
Scheme 465
The active control engine mount system decreases engine vibration at a low engine speed using the duty vacuum switching valve. The duty vacuum switching valve is controlled by a pulse signal transmitted to the duty vacuum switching valve from the ECM. The frequency of this pulse signal is matched to the engine speed to decrease engine vibration.
Scheme 466
When the ignition switch is turned ON, the 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 contact of the EFI MAIN relay and supplying power to terminals +B and +B2 of the ECM.
Scheme 467
The ECM constantly uses 5 V from the battery voltages 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 468
When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied 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 ON. The MIL goes off when the engine is started.
Scheme 469
Scheme 470
Refer to DTC P0230. Refer to DESCRIPTION.
The fuel injector assemblies are located on the intake manifold. They inject fuel into the cylinders based on signals from the ECM.
Scheme 471
While the engine is being cranked, current flows from terminal ST2 of the ignition switch to the park/neutral position switch and also flows to terminal STA of the ECM (STA signal).
Scheme 472
The cranking holding control system keeps energizing the ST relay from when the power management control ECU detects the starter signal from the ignition switch assembly until the power management control ECU performs a judgement of "Engine started".
When the power management control ECU detects the STSW signal, the power management control ECU outputs the ST relay drive signal (STAR signal) to the ST relay through the park/neutral position switch assembly, and then, the engine is cranked. When the power management control ECU receives a stable engine speed signal (NE signal), more specifically, when the NE signal reaches a predetermined value, the power management control ECU stops outputting the STAR signal.
Also, the power management control ECU monitors the ST relay operating conditions based on the STA terminal voltage status.
Scheme 473
This circuit opens and closes the intake air control valve (intake air surge tank assembly) in response to changes in the engine load in order to increase the intake efficiency using the acoustic control induction system.
When the engine speed is between 0 and 4300 RPM and the throttle valve opening angle is 60° or more, the ECM supplies current to the actuator (on status), to close the intake air control valve. Under other conditions, the VSV is usually off and the intake air control valve is open.
Scheme 474
Scheme 475
The air cleaner filter element sub-assembly is equipped with 2 inlets, one of which is opened or closed by the air intake control valve (intake air surge tank assembly). This system reduces intake noise and increases engine power at low-to-high engine speed ranges.
When the engine is operating in the low-to-mid speed range, this control operates the air intake control valve to close one of the air cleaner filter element sub-assembly inlets. When the engine speed is more than 3600 RPM and the opening angle of the throttle valve is more than 60°, the ECM activates the vacuum switching valve (for AICS) and opens the air intake control valve.
Scheme 476
Scheme 477
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 478
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 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 Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM. By turning the ignition switch 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 ON, the MIL should illuminate and should then turn off. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure. If the ECM detects any trouble, the MIL illuminates. At this time, the ECM records a DTC in the memory.
