Engine Control System (2TR-FE) (Diagnostic Codes (P1613 - P2610) & Circuit Tests)): Overview Toyota Tacoma II рестайлинг

DESCRIPTION

Refer to DTC P0412. Refer to DESCRIPTION.

MONITOR DESCRIPTION

For a short time after cold engine starts, the ECM transmits command signals to the air injection control driver to drive the air pump assembly and the air switching valve assembly. The air injection control driver detects open and short circuits according to the voltages at the air injection control driver terminals to the air pump assembly and air switching valve assembly, and the circuit voltage of the air injection control driver power source, and transmits diagnostic information as a signal to the ECM.

If the secondary air injection system circuit or the air injection control driver itself malfunctions, the air injection control driver sends a malfunction signal (duty signal) as diagnostic information to the ECM (when the system is normal, a system normal signal is sent). The ECM stores the DTC based on the diagnostic information from the air injection control driver.

EXAMPLE

1. The duty ratio of the diagnostic signal from the air injection control driver is 0 or 100% (remains at 0 V or the same as battery voltage).
2. The duty ratio of the diagnostic signal from the air injection control driver shows an impossible ratio (other than 0, 20, 40, 80 and 100%).
3. The air injection control driver outputs the normal signal (normal duty signal: 80%) while the system is not operating.

The throttle actuator is operated by the ECM and opens and closes the throttle valve using gears.

The opening angle of the throttle valve is detected by the throttle position sensor, which is mounted on the throttle 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 (ETCS) does not use a throttle cable.

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 the DTC.

Example

When the electrical current is less than 0.5 A and the throttle actuator duty ratio exceeds 80%, the ECM interprets this as the current being outside the standard range, and illuminates the MIL and stores the 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 electronic throttle control system 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.

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 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

1. 1) The mass air flow meter is normal.
2. 2) Atmospheric pressure is 85 kPa(abs) [637.5 mmHg(abs)] or higher.
3. 3) The vehicle has been driven at a speed of 30 km/h (18.6 mph) or more at least once.
4. 4) The engine coolant temperature is 45°C (113°F) or less at engine start, the engine is warmed up and conditions for ISC learning are met, or the ignition switch has been turned to ON (include engine running) for 1 hour or more, the engine is warmed up and conditions for ISC learning are met.

The throttle actuator is operated by the ECM, and opens and closes the throttle valve using gears. The opening angle of the throttle valve is detected by the throttle position sensor, which is mounted on the throttle body assembly. The throttle position sensor provides feedback to the ECM so that the ECM can control the throttle actuator (throttle valve) appropriately in response to driver inputs.

HINT

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

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 the 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 (ETCS) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (less than 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 ETCS does not use a throttle cable.

Scheme 219

The ECM monitors the battery supply voltage applied to the throttle actuator.

When the power supply voltage (+BM) drops less than 4 V for 0.8 seconds or more, the ECM interprets this as an open in the power supply circuit (+BM). The ECM illuminates the MIL and stores the DTC.

If the malfunction is not repaired successfully, the DTC is stored 5 seconds after the engine is next started.

The Electronic Throttle Control System (ETCS) is composed of the throttle actuator, throttle position sensor, accelerator pedal position sensor and ECM. The ECM operates the throttle actuator to regulate the throttle valve in response to driver inputs. The throttle position sensor detects the opening angle of the throttle valve, and provides the ECM with feedback so that the throttle valve can be appropriately controlled by the ECM.

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 ETCS. The ECM then illuminates the MIL and stores the DTC.

If the malfunction is not repaired successfully, the DTC is stored when the accelerator pedal is quickly released (to close the throttle valve) after the engine speed reaches 5000 rpm by the accelerator pedal being fully depressed (fully open the throttle valve).

HINT

1. These DTCs relate to the accelerator pedal position sensor.
2. This Electronic Throttle Control System (ETCS) does not use a throttle cable.
3. 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.

The accelerator pedal position sensor is built into the accelerator pedal assembly 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 4.75 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 220

HINT

When any of these DTCs are stored, check the accelerator pedal position sensor voltage by entering the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

HINT

Accelerator pedal positions are expressed as voltages.

When either of the voltage outputs of VPA or VPA2 deviates from the standard range, or the difference between the voltage outputs of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the accelerator pedal sensor assembly. The ECM then illuminates the MIL and stores the DTC.

Example

When the voltage output 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.
2. Refer to DTC P2120. Refer to «DTC P2120: Throttle / Pedal Position Sensor / Switch "D" Circuit; DTC P2122: Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input; DTC P2123: Throttle / Pedal Position Sensor / Switch "D" Circuit High Input; DTC P2125: Throttle / Pedal Position Sensor / Switch "E" Circuit; DTC P2127: Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input; DTC P2128: Throttle / Pedal Position Sensor / Switch "E" Circuit High Input; DTC P2138: Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation»(ref-554495-S21429764782013052000000).

The accelerator pedal position sensor is mounted on the accelerator pedal sensor 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 sensor is malfunctioning. The ECM turns on the MIL and the DTC is stored.

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), current flows into the heater to heat the sensor, in order to facilitate accurate air fuel ratio detection. The heat generated by the heater is conducted to the solid electrolyte through the alumina, 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 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 the current output element, a 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 221

HINT

1. When any of these DTCs are stored, check the air fuel ratio sensor voltage output by entering the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1.
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 the air fuel ratio sensor is malfunctioning, the ECM stores the DTC P2195 or P2196.

Scheme 222

1. 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 rear heated oxygen sensor output voltage being less than 0.66 V, the ECM stores DTC P2196. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (very lean condition) for 5 seconds despite the rear heated oxygen sensor output voltage being 0.21 V or higher, DTC P2195 is stored.
2. 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 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 less than 0.7 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 (stuck on low side).

Refer to P0300. Refer to DESCRIPTION.

Refer to P2195. Refer to DESCRIPTION.

Fuel System Air Fuel Ratio Cylinder Imbalance Monitor

The ECM uses the air fuel ratio sensor and crankshaft position sensor to monitor the difference in air fuel ratios between the cylinders caused by differences in injection volumes between the cylinders, leakage in the intake or exhaust system, etc.

When the air fuel ratios of the cylinders are lean or rich with respect to each other, the ECM determines that a problem is present and stores the DTC.

Air Fuel Ratio Sensor Monitoring Method

When the system detects a difference in air fuel ratios between the cylinders due to fluctuation in the air fuel ratio sensor output over 1 engine cycle (2 crankshaft revolutions), the system determines that there is a problem.

Crankshaft Position Sensor Monitoring Method

The system monitors the engine speed variation and when the variation becomes large, the system determines that there is a difference in air fuel ratios between the cylinders, which it determines to be a problem.

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.
3. Refer to DTC P2195. Refer to «DESCRIPTION»(ref-554495-S34068545742013052000000).

These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if 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 the ON position, 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 outside of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in the 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 (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.

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

Scheme 223

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 224

The secondary air injection system consists of an air pump assembly, the air switching valve assembly, an air pressure sensor, the air injection control driver and the ECM. For a short time after cold engine starts, the secondary air injection system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The secondary air is supplied by the air pump assembly and is pumped to the exhaust port through the air switching valve assembly.

The air injection control driver drives the air switching valve assembly and the air pump assembly according to command signals transmitted by the ECM. The air pressure sensor detects the pressure in the secondary air passage when the secondary air injection system is ON and OFF, and transmits pressure signal to the ECM.

The air injection control driver is not only equipped to drive the pump and valve, but also with a diagnosis function to detect malfunctions in the secondary air injection system circuit.

HINT

As a large current is required to drive the air pump assembly and air switching valve assembly, an air injection control driver is included in this system.

Scheme 225

Scheme 226

The ECM monitors the pressure in the secondary air passage using the air pressure sensor located on the air switching valve assembly in the secondary air injection system.

If there is a defect in the sensor or the sensor circuit, the voltage level deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the air pressure sensor or circuit and stores a DTC.

Refer to DTC P0412. Refer to DESCRIPTION.

HINT

Air switching valve normal operation

When the air switching valve assembly is open, exhaust gas pulsation occurs in the secondary air passage.

When the air switching valve assembly is closed, exhaust gas pulsation does not occur in the secondary air passage.

Air switching valve assembly of the secondary air injection system.

If either of the following conditions occurs, the ECM interprets it as a malfunction of the secondary air injection system, and illuminates the MIL and stores a DTC

1. Exhaust gas pulsation is detected by the air pressure sensor despite the ECM commanding the air switching valve assembly to close.
2. Exhaust gas pulsation is not detected by the air pressure sensor despite the ECM commanding the air switching valve assembly to open.

Refer to P0412. Refer to DESCRIPTION.

The ECM monitors the pressure in the secondary air passage using the air pressure sensor located on the air switching valve assembly of the secondary air injection system. The sensor measures the pressure in the secondary air passage and transmits a signal to the ECM.

If either of the following conditions occurs, the ECM interprets it as a malfunction of the secondary air injection system, and illuminates the MIL and stores a DTC

1. The pressure indicated by the air pressure sensor does not reach threshold levels despite the ECM turning on the air pump assembly.
2. The pressure indicated by the air pressure sensor exceeds threshold levels despite the ECM turning off the air pump assembly.

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 227

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.

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 current to flow to the coil, closing the contacts of the EFI MAIN relay and supplying power to terminal +B of the ECM.

Scheme 228

The ECM constantly generates 5 V power from the 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 229

When the VC circuit is short-circuited, 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 to ON. The MIL goes off when the engine is started.

When the engine is cranked, current flows from terminal ST2 of the ignition switch into the STA (starter) relay coil and current also flows into terminal STA of the ECM (STA signal).

When the STA and NE signals are received by the ECM, Tr (power transistor) is switched on, allowing current to flow into the circuit opening relay coil. The circuit opening relay switches on, power is supplied to the fuel pump and the fuel pump operates.

While the NE signal is being generated (engine running), the ECM keeps Tr ON, therefore keeping the circuit opening relay ON, so that the fuel pump continues to operate.

Scheme 230

Scheme 231

The fuel injectors inject fuel based on the signals from the ECM.

Scheme 232

While the engine is being cranked, current flows from terminal ST1 of the ignition switch to the STA relay and also flows to terminal STA of the ECM (STA signal). The ECM uses the STA signal to control the fuel injection and ignition timing when the engine starts.

Scheme 233

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 234

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 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 MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections 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 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 235

See also:
• ON-VEHICLE INSPECTION - Step 4
• ON-VEHICLE INSPECTION - Step 2
• ON-VEHICLE INSPECTION - Step 2
• ON-VEHICLE INSPECTION - Step 11
• REMOVAL