Contents Section: Testing & Diagnostics All sections

Engine Control System (1AR-FE) (Diagnostic Codes (P1604 - U0101) & Circuit Tests): Overview Toyota Highlander II рестайлинг

Testing & Diagnostics 30 illustrations ~5282 words

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 ConditionTrouble Area
P1604Either 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 assembly Crankshaft position sensor Camshaft position sensor Engine coolant temperature sensor Fuel pump Fuel pump control system Fuel pipes Fuel injector Throttle body Fuel 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

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Scheme 77

Scheme 77
  1. Reference waveforms showing a normal cold engine start
  2. Reference waveforms showing a normal warm engine start
  3. Reference waveforms showing an engine stop after normal idling
  4. Reference values when there is an air leak in the intake system during starting difficulty FREEZE FRAME DATA P1604 STARTABILITY MALFUNCTION Parameter -3 -2 -1 0 1 Unit Engine Speed 398 325 221 159 114 RPM Calculate Load 43.1 42.7 43.1 87.4 87.4 % Vehicle Load 28.2 26.2 26.6 17.2 15.0 % MAF 3.01 2.28 1.59 0.75 0.48 gm/sec Atmosphere Pressure 14.5 14.5 14.5 14.5 14.5 psi (gauge) Coolant Temp 185 185 185 185 185 F Intake Air 115 115 115 115 115 F Battery Voltage 12.460 12.382 12.324 12.324 12.343 V Throttle Sensor Volt % 16.4 16.0 17.6 16.0 16.0 % Throttle Sensor #2 Volt % 48.6 47.8 49.8 47.8 47.8 % Throttle Sensor Position 0.0 0.0 0.0 0.0 0.0 % Throttle Motor DUTY 17.6 16.0 16.0 16.0 16.0 % Injector (Port) 4240 4302 4612 4612 7776 μs Injection Volume (Cylinder 1) 0.274 0.274 0.187 0.187 0.187 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 Target Air-Fuel Ratio 0.864 0.873 0.882 0.883 0.830 AF Lambda B1S1 0.999 0.999 1.001 1.002 1.005 AFS Voltage B1S1 3.298 3.298 3.307 3.312 3.327 V O2S B1 S2 0.015 0.015 0.015 0.015 0.015 V Short FT #1 0.000 0.000 0.000 0.000 0.000 % Long FT #1 3.906 3.906 3.906 3.906 3.906 % Total FT #1 0.000 0.000 0.000 0.000 0.000 Fuel System Status #1 OL OL OL OL OL IGN Advance 8.0 7.0 6.0 0.0 0.0 deg Knock Feedback Value -3.0 -3.0 -3.0 -3.0 -3.0 CA Knock Correct Learn Value 19.0 19.0 19.0 19.0 19.0 CA VVT Control Status #1 OFF OFF OFF OFF OFF Starter Signal Close Close Close Close Close

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 ConditionTrouble Area
P1607An ECM internal error (1 trip detection logic)ECM

The tumble control valve is built into the intake manifold. The tumble control valve is composed of a position sensor and a DC motor. The DC motor opens and closes the tumble control valve in response to signals from the ECM. The position sensor detects the opening angle of the tumble control valve.

When the tumble control valve 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 ConditionTrouble Area
P2004 (Stuck open)When the tumble control valve opening angle is 17 deg or more after requesting the tumble control valve to fully close (2 trip detection logic).DC Motor for tumble control valve circuit DC Motor for tumble control valve Tumble control valve position sensor Tumble control valve ECM
P2006 (Stuck closed)When the tumble control valve opening angle is less than 35 deg after requesting the tumble control valve to fully open (2 trip detection logic).

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 operationIntake Air Control Position
100%Approximately 70 deg
0%Approximately 70 deg
100%Approximately 2 deg

REFERENCE (NORMAL CONDITION)

Engine Coolant Temperature and Intake Air Temperature at Engine StartIntake Air Control Position
10°C (14°F) or lessApproximately 70 deg
60°C (140°F) or higherApproximately 70 deg
10 to 60°C (14 to 140°F)Approximately 2 deg

REFERENCE (NORMAL CONDITION)

When the ECM has requested a tumble control valve close operation but the actual tumble control valve opening angle is 17 deg or more for 10 seconds, DTC P2004 is output. When the ECM has requested a tumble control valve open operation but the actual tumble control valve opening angle is less than 35 deg for 10 seconds, DTC P2006 is output.

The ECM activates the DC motor for the tumble control valve, which opens and closes the tumble control valve. The ECM activates the DC motor based on engine speed, coolant temperature, intake air temperature and other conditions.

DTC No.DTC Detection ConditionTrouble Area
P2009Both of the following conditions continue for 1 second (1 trip detection logic): (a) The output duty of the DC motor for the tumble control valve is 100%. (b) The current of the DC motor for the tumble control valve is below 0.35 A.Open or short in DC motor for tumble control valve circuit Intake manifold (DC motor for tumble control valve) ECM
P2010Either of the following conditions continues for 6 times or more (1 trip detection logic): (a) The motor drive IC is overcurrent. (b) The motor drive IC overheats.

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 position sensor is a non-contact type sensor.

The position sensor measures the opening angle of the tumble control valve. The sensor is reliable and accurate, as it is electrically controlled by Hall elements.

Scheme 78

Scheme 78: DESCRIPTION
DTC No.DTC Detection ConditionTrouble Area
P2014The tumble control valve 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 tumble control valve position sensor circuit Tumble control valve position sensor ECM
P2016The tumble control valve position sensor output voltage is below 0.2 V for more than 0.5 seconds (short) (1 trip detection logic).
P2017The tumble control valve position sensor output voltage is higher than 4.8 V for more than 0.5 seconds (open) (1 trip detection logic).

HINT

After confirming DTC P2014, P2016 or P2017, use the Techstream to confirm the IAC Sensor Voltage (tumble control valve position sensor output voltage). Enter the following menus: Powertrain / Engine / Data List / All Data / IAC Sensor Voltage.

IAC Sensor VoltageMalfunction
0.2 V or lessIAC1 circuit shorted VCIA circuit open
4.8 V or higherVCIA and IAC1 circuit shorted IAC1 circuit open EIA1 circuit open

The ECM IAC1 terminal voltage increases in correlation with the opening angle of the tumble control valve. When the tumble control valve is fully closed, approximately 0.8 V is applied to the IAC1 terminal. When the tumble control valve 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 sensor, which is mounted on 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 Electronic Throttle Control System (ETCS) does not use a throttle cable.

DTC No.DTC Detection ConditionTrouble Area
P2102Both 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
P2103Either 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.

  1. 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 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 ConditionTrouble Area
P2109The 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

  1. The ISC learned value is the calculated intake air amount corresponding to the throttle opening amount necessary to maintain the idling speed.
  2. 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.
  3. The system uses the throttle 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 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 manifold absolute pressure sensor is normal; 2) atmospheric pressure is 85 kPa (638 mmHg) or higher; 3) the vehicle has been driven at a speed of 19 mph (30 km/h) 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 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. 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 (ETCS) does not use a throttle cable.

DTC No.DTC Detection ConditionTrouble Area
P2111The ECM signals the throttle actuator to close, but the actuator is stuck (1 trip detection logic).Throttle actuator Throttle body Throttle valve ECM Wire harness or connector
P2112The ECM signals the throttle actuator to open, but the actuator is stuck (1 trip detection logic).Throttle actuator Throttle body Throttle valve ECM Wire harness or connector

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 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

The electronic throttle control system does not use a throttle cable.

Scheme 79

Scheme 79: DESCRIPTION
DTC No.DTC Detection ConditionTrouble Area
P2118An open in the 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 ConditionTrouble Area
P2119The throttle valve opening angle continues to vary greatly from the target opening angle (1 trip detection logic).Electronic throttle control system ECM Wire harness or connector

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 two 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 fully depressing the accelerator pedal (fully open the throttle valve).

HINT

  1. This Electronic Throttle Control System (ETCS) does not use a throttle cable.
  2. These DTCs relate to the accelerator pedal position sensor.

The accelerator pedal position 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 accelerator pedal position 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 80

Scheme 80
DTC No.DTC Detection ConditionTrouble Area
P2120VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).Accelerator pedal position sensor ECM
P2122VPA 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 sensor Open in VCP1 circuit Open or ground short in VPA circuit ECM
P2123VPA is 4.8 V or higher for 2.0 seconds or more (1 trip detection logic).Accelerator pedal position sensor Open in EPA circuit ECM
P2125VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).Accelerator pedal position sensor ECM
P2127VPA2 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 sensor Open in VCP2 circuit Open or ground short in VPA2 circuit ECM
P2128Both 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 sensor Open in EPA2 circuit ECM
P2138Either 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 sensor 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 / Data List / All Data / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

Trouble AreaAccel Sensor Out No. 1 When Accelerator Pedal ReleasedAccel Sensor Out No. 2 When Accelerator Pedal ReleasedAccel Sensor Out No. 1 When Accelerator Pedal DepressedAccel Sensor Out No. 2 When Accelerator Pedal Depressed
Open in VCPA or VCP2 circuit0 to 0.2 V0 to 0.2 V0 to 0.2 V0 to 0.2 V
Open or ground short in VPA circuit0 to 0.2 V1.2 to 2.0 V0 to 0.2 V3.4 to 4.98 V
Open or ground short in VPA2 circuit0.5 to 1.1 V0 to 0.2 V2.6 to 4.5 V0 to 0.2 V
Open in EPA or EPA2 circuit4.5 to 4.98 V4.5 to 4.98 V4.5 to 4.98 V4.5 to 4.98 V
Normal condition0.5 to 1.1 V1.2 to 2.0 V2.6 to 4.5 V3.4 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 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

  1. This DTC relates to the accelerator pedal position sensor.

Refer to DTC P2120, refer to DESCRIPTION.

DTC No.DTC Detection ConditionTrouble Area
P2121The difference between VPA and VPA2 is below 0.4 V, or higher than 1.2 V for 0.5 seconds (1 trip detection logic).Accelerator pedal position 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 stores the DTC.

HINT

  1. Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
  2. 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 level, 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 the planar type 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 the narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, 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 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 81

Scheme 81
DTC No.DTC Detection ConditionTrouble Area
P2195Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic) (a) Air fuel ratio sensor voltage higher than 3.8 V (b) Heated oxygen sensor voltage is 0.21 V or higherOpen or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) Air fuel ratio sensor (bank 1 sensor 1) heater Air fuel ratio sensor heater circuit Intake system Fuel pressure Fuel injector assembly ECM
While fuel-cut operation performed (during vehicle deceleration), air fuel ratio sensor current is 3.6 mA or more for 3 seconds (2 trip detection logic)Air fuel ratio sensor (bank 1 sensor 1) ECM
P2196Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic) (a) Air fuel ratio sensor voltage below 2.8 V (b) Heated oxygen sensor voltage is below 0.59 VOpen or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) Air fuel ratio sensor (bank 1 sensor 1) heater Air fuel ratio sensor heater circuit Intake system Fuel pressure Fuel injector assembly ECM
While fuel-cut operation performed (during vehicle deceleration), air fuel ratio sensor current is less than 1.0 mA for 3 seconds (2 trip detection logic)Air fuel ratio sensor (bank 1 sensor 1) ECM

HINT

  1. When any of these DTCs are set, check the air fuel ratio sensor voltage output by entering the following menus on the Techstream: Powertrain / Engine / Data List / All Data / AFS Voltage B1 S1.
  2. Short-term fuel trim values can also be read using the Techstream.
  3. The ECM regulates the voltages at the A1A+ and A1A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor voltage output cannot be confirmed without using the Techstream.
  4. If an air fuel ratio sensor malfunction is detected, the ECM sets a DTC.

Sensor Voltage Detection Monitor

Under the air fuel ratio feedback control, if the air fuel ratio sensor voltage output indicates rich or lean 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 voltage output is below 2.8 V (very rich condition) and heated oxygen sensor output voltage below 0.59 V for 5 seconds, the ECM stores DTC P2196. Alternatively, if the air fuel ratio sensor voltage output is higher than 3.8 V (very lean condition) and heated oxygen sensor output voltage 0.21 V or more for 5 seconds, 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 below 1.0 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 (stuck on low side).

Scheme 82

Scheme 82: MONITOR DESCRIPTION

HINT

  1. Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
  2. 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, 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 83

Scheme 83

Scheme 84

Scheme 84
DTC No.DTC Detection ConditionTrouble Area
P2237An 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 in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2238Case 1 Condition (a) or (b) continues for 5.0 seconds or more (2 trip detection logic) (a) Voltage at terminal A1A+ is 0.5 V or less. (b) Voltage difference between terminals A1A+ and A1A- is 0.5 V or less. Case 2 Air fuel ratio sensor admittance: Less than 0.015 1/ohms (2 trip detection logic)Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2239The A1A+ voltage is higher than 4.5 V (2 trip detection logic).Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2252The A1A- voltage is 0.5 V or less (2 trip detection logic).Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2253The A1A- voltage is higher than 4.5 V (2 trip detection logic).Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM

These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if the air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio 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 air fuel ratio 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 air fuel ratio 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*1 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

*1: 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.

SequenceOperationDescriptionDuration
ECM activationActivated by soak timer 5, 7 or 9.5 hours after ignition switch turned off.
AAtmospheric pressure measurementVent 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
BFirst reference pressure measurementIn 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
CEVAP system pressure measurementVent 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*2
DPurge VSV monitorPurge VSV opened and then EVAP system pressure measured by ECM. Large increase indicates normality.10 seconds
ESecond reference pressure measurementAfter 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 checkAtmospheric pressure measured and then monitoring result recorded by ECM.

*2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

Scheme 85

Scheme 85

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 86

Scheme 86

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 87

Scheme 87: DESCRIPTION
  1. 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.
  2. 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

  1. Refer to DTC P2195, refer to «DESCRIPTION»(ref-422453-S19738957562011092600000).
  2. 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 ConditionTrouble Area
P2A00The calculated value for the air fuel ratio sensor response rate deterioration level is less than the threshold. (2 trip detection logic)Air fuel ratio sensor (bank 1 sensor 1) Air fuel ratio sensor heater (bank 1 sensor 1) 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 air fuel ratio control is performed for approximately 10 seconds after preconditions are met in order to measure the air fuel ratio sensor response rate. During active air fuel ratio control, the ECM forcibly increases and decreases the injection volume by 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 air fuel ratio control and uses it to calculate the air fuel ratio sensor response rate deterioration level.

If the value for 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 88

Scheme 88: MONITOR DESCRIPTION

The Engine Control Module (ECM) intercommunicates with the Transmission Control Module (TCM) through the Controller Area Network (CAN).

If there is a problem in this intercommunication, the ECM sets a DTC.

DTC No.DTC Detection ConditionTrouble Area
U0101Following 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 TCMECM to TCM circuit TCM ECM

When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The ECM MREL output signal causes a current to flow to the coil, closing the contacts of the EFI relay and supplying power to terminal +B, +B2 of the ECM.

If the ignition switch is turned off, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

Scheme 89

Scheme 89: WIRING DIAGRAM

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 90

Scheme 90: DESCRIPTION

When the VC circuit is shorted, 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.

Scheme 91

Scheme 91: WIRING DIAGRAM

Scheme 92

Scheme 92

When the engine is cranked, the starter relay drive signal output from the ignition switch 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. When the ECM interprets that the engine is cranked, it turns transistor Tr1 in the ECM internal circuit on. The current flows to the C/OPN (Circuit Opening) relay when Tr1 is turned 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 93

Scheme 93: DESCRIPTION

Scheme 94

Scheme 94: WIRING DIAGRAM

The fuel injectors are located on the intake manifold. They inject fuel into the cylinders based on the signals from the ECM.

Scheme 95

Scheme 95: WIRING DIAGRAM

While the engine is being cranked, current flows from terminal ST1 of the ignition switch to the park/neutral position switch and also flows to terminal STA of the ECM (STA Signal).

Scheme 96

Scheme 96: WIRING DIAGRAM

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 97

Scheme 97: DESCRIPTION

Scheme 98

Scheme 98: WIRING DIAGRAM

The air cleaner is equipped with two inlets, one of which is opened or closed by the Air Intake Control Valve (AICV). This system reduces intake noise and increases engine power at low-to-high engine speed range.

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 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 VSV and opens the air intake control valve.

Scheme 99

Scheme 99: DESCRIPTION

Scheme 100

Scheme 100: WIRING DIAGRAM

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 101

Scheme 101: DESCRIPTION

Activation Conditions

  1. Vehicle is running at or above the specified speed.
  2. 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

  1. 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

  1. 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. 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 should be illuminated and should then turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.

Scheme 102

Scheme 102: WIRING DIAGRAM

Scheme 103

Scheme 103: PROCEDURE
  1. CHECK THAT MIL IS ILLUMINATED Turn the ignition switch to ON. Check the illumination of the MIL. Result Result Proceed to MIL remains illuminated (Even after ignition switch is turned to ON and several seconds have passed, MIL still remains illuminated) A MIL remains off (Does not illuminate at all) B B --> See step 5 A: Go to next step
  2. CHECK WHETHER MIL TURNS OFF Connect the Techstream to the DLC3. Turn the ignition switch to ON and turn the Techstream on. Enter the following menus: Powertrain / Engine / Trouble Code. Check if any DTCs have been stored. Note down any DTCs. Clear the DTCs, refer to «DTC CHECK / CLEAR»(ref-422301-S01463917032011092600000). Check if the MIL goes off. OK MIL goes off. NG --> See step 3 OK --> See step 8
  3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) Disconnect the ECM connector. Turn the ignition switch to ON. Check that the MIL is not illuminated. OK MIL is not illuminated. Reconnect the ECM connector. NG --> See step 4 OK --> See step 9
  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) Disconnect the ECM connector. Disconnect the combination meter assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Short) Tester Connection Condition Specified Condition D60-18 (W) or E1-10 (CHK) - Body ground Always 10 kohms or higher Reconnect the ECM connector. Reconnect the combination meter assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 10
  5. CHECK THAT ENGINE STARTS Turn the ignition switch to ON. Start the engine. Result Result Proceed to Engine starts A Engine does not start* B HINT: *: The Techstream cannot communicate with the ECM. B --> See step 11 A: Go to next step
  6. CHECK HARNESS AND CONNECTOR (COMBINATION METER - BODY GROUND) Disconnect the ECM connector. Turn the ignition switch to ON. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition D60-18 (W) - Body ground Ignition switch ON 11 to 14 V Reconnect the ECM connector. NG --> See step 7 OK --> See step 9
  7. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM) Disconnect the ECM connector. Disconnect the combination meter assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Condition Specified Condition D60-18 (W) - E1-10 (CHK) Always Below 1 ohms Reconnect the ECM connector. Reconnect the combination meter assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 10
  8. REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-422301-S13330058002011092600000)
  9. REPLACE ECM. Refer to «REMOVAL»(ref-422454-S15687586072011092600000)
  10. REPLACE COMBINATION METER ASSEMBLY. Refer to «REMOVAL»(ref-422472-S27297988222011092600000)
  11. GO TO VC OUTPUT CIRCUIT. Refer to «VC Output Circuit»(ref-422453-S10585726272011092600000)