Engine Control System (2TR-FE) (Diagnostic Codes (P0451 - P1607)): Overview Toyota Tacoma II рестайлинг

DESCRIPTION

The description can be found in the EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

Scheme 383

1. DTC P0451: Canister pressure sensor noise If the canister pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as noise from the canister pressure sensor, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC. (2 trip detection logic).
2. DTC P0452: Canister pressure sensor voltage low If the canister pressure sensor voltage output [pressure] is below 0.45 V: 42.11009 kPa(abs) [315.86779 mmHg(abs)], the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC (1 trip detection logic).
3. DTC P0453: Canister pressure sensor voltage high If the canister pressure sensor voltage output [pressure] is 4.9 V: 123.76147 kPa(abs) [928.33489 mmHg(abs)] or more, the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC (1 trip detection logic).

The description can be found in EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

MONITOR DESCRIPTION

5 hours*1 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 384

TEXT IN ILLUSTRATION

Scheme 385

1. (a) P0455: EVAP (Evaporative Emission) gross leak In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than [second reference pressure x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large leak, illuminates the MIL and stores the DTC (2 trip detection logic).
2. (b) P0456: EVAP very small leak In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than second reference pressure, the ECM determines that the EVAP system has a small leak, illuminates the MIL and stores the DTC (2 trip detection logic).

Vehicles which are equipped with ABS (Anti-lock Brake System) detect the vehicle speed using the skid control ECU (brake actuator assembly) and wheel speed sensor. The wheel speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU (brake actuator assembly). The skid control ECU (brake actuator assembly) converts the wheel speed signal into a 4-pulse signal and transmits it to the ECM via the combination meter assembly. The ECM determines the vehicle speed based on the frequency of the pulse signal.

Scheme 386

Automatic Transmission Models

The ECM assumes that the vehicle is being driven when the indicated vehicle speed is 9 km/h (5.59 mph) or more. If there is no speed signal from the combination meter assembly despite these conditions being met, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then illuminates the MIL and stores the DTC.

Manual Transmission Models

The ECM assumes that the vehicle is being driven when the idle fuel-cut operation* is being executed. If there is no signal from the vehicle speed sensor, despite these conditions being met, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then illuminates the MIL and stores the DTC.

*: Idle fuel-cut is executed when the throttle valve is fully closed and engine speed is over 2800 RPM.

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and stores the DTC.

HINT

The normal conditions are as shown in the table below.

1. [OFF] denotes ground potential.
2. [ON] denotes battery potential (+B).
3. On the Techstream, both the Data List items Stop Light Switch and ST1 are ON when the brake pedal is depressed because the ST1 indication characteristic is opposite to the Stop Light Switch indication.

Scheme 387

The idling speed is controlled by the Electronic throttle control system. The electronic throttle control system is comprised of: 1) the one valve type throttle body; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; and 5) the ECM, which controls the electronic throttle control system. Based on the target idling speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

The ECM monitors the idling speed and idling air flow volume to conduct idle speed control. The ECM determines that the idle speed control system is malfunctioning if the following conditions are met

1. The difference between the target engine idling speed and actual engine idling speed exceeds the threshold and the IAC flow rate learned value is stuck at the upper or lower limit for 5 seconds or more.
2. After driving at a vehicle speed of 10 km/h (6.25 mph) or more, the difference between the target and actual engine idling speed exceeds the threshold 5 times or more during a driving cycle, and then the system determines that the IAC flow rate learned value is stuck at the upper or lower limit, or that the IAC flow rate learned value has been changed by an amount that exceeds the threshold.

Scheme 388

This monitor will run when the engine is started with the engine coolant temperature at -10 to 50°C (14 to 122°F). The DTC will be stored after the engine idles for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started with the engine coolant temperature at lower than 50°C (122°F), the ECM measures the accumulated mass air flow at engine idling. If it does not reach the criteria within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.

Note. When the cable is disconnected from the negative battery terminal during inspections or repairs, the idle speed control learning values are cleared. This DTC cannot be stored with the idle speed control learning values cleared.

HINT

The idle speed control learning is performed when the engine is warmed up and has been idling for 5 minutes.

Scheme 389

This monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). The DTC will be stored after the engine idles for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the ignition timing at cold start. When the engine is started at an engine coolant temperature of less than 50°C (122°F), the ECM checks the ignition timing at engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

Note. When the cable is disconnected from the negative battery terminal during inspections or repairs, the ISC (Idle Speed Control) learning values are cleared. This DTC cannot be stored with the ISC learning values cleared.

HINT

The ISC learning is performed when the engine is warmed up and has been idling for 5 minutes.

Scheme 390

The battery supplies electricity to the ECM even when the ignition switch is in the OFF position. This power allows the ECM to store data such as DTC history, freeze frame data and fuel trim values. If the battery voltage falls below a minimum level, the stored ECM data is cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM illuminates the MIL and stores the DTC.

HINT

If DTC P0560 is stored, the ECM does not store other DTCs and the data stored in the ECM is partly cleared.

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is functioning properly. This is diagnosed by internal "mirroring" of the main CPU and sub CPU to detect the Random Access Memory (RAM) errors. If outputs from these CPUs are different and deviate from the standard, the ECM will illuminate the MIL and stores the DTC immediately.

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 illuminates the MIL and stores the DTC immediately.

The ECM continuously monitors its internal processors (CPUs), and heated oxygen sensor transistors. This self-check ensures that the ECM is functioning properly.

The main CPU and sub CPU of the ECM perform data communication between each other. The main CPU monitors the communications and WDC pulses from the sub CPU. When the signal malfunctions below are detected, this DTC is stored.

This DTC is stored when a communication error occurs in the ECM.

The ECM monitors the input signals of the accelerator pedal position sensor No. 1. When the input signals and control signals deviate, this DTC is stored.

The ECM monitors the input signals of the throttle position sensor No. 1 and stop light switch. As the ECM monitors the input signals of the throttle position sensor No. 1 and the STP signals of the stop light switch, if the input signals and control signals deviate, this DTC is stored.

While the engine is being cranked, the positive battery voltage is applied to terminal STA of the ECM.

If the ECM detects the Starter Control (STA) signal while the vehicle is being driven, it determines that there is a malfunction in the STA circuit. The ECM then illuminates the MIL and stores the DTC.

This monitor runs when the vehicle is driven at 20 km/h (12.4 mph) for over 20 seconds.

1. *1: for Automatic Transmission Models
2. *2: for Manual Transmission Models

The ECM monitors its internal operation and stores this DTC when it detects an internal malfunction.

The ECM monitors its internal operation. If there is an internal operation malfunction, the ECM illuminates the MIL and stores a DTC.

DTC P0630 is stored when the Vehicle Identification Number (VIN) is not stored in the Engine Control Module (ECM) or the input VIN is not accurate. Input the VIN with the Techstream.

The ECM monitors the output voltage to the throttle actuator. This self-check ensures that the ECM is functioning properly. The output voltage usually is 0 V when the ignition switch is turned OFF. If the output voltage is 7 V or higher when the ignition switch is turned OFF, the ECM will illuminate the MIL and stores the DTC when the ignition switch is turned ON.

The stop light switch is part of a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly. This DTC indicates that the stop light switch remains on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC.

This DTC indicates that the stop light switch remains ON. When the stop light switch remains ON during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC. The vehicle must GO (30 km/h (18.64 mph) or more) and STOP (less than 3 km/h (1.86 mph)) 5 times for 2 driving cycles in order for the DTC to be output.

HINT

*: Name of Data List item

This DTC is stored when a deviation from air pressure sensor characteristics is detected.

The air pressure sensors* are checked 55 minutes after the ignition switch is turned off. If the pressures detected by the air pressure sensors* differ by a certain amount, the MIL is illuminated and a DTC is stored (2 trip detection logic).

HINT

1. *: P106B checks the canister pressure sensor and the air pressure sensor of the air switching valve (Bank 1).
2. Correct judgment may not be possible when the altitude is 4000 m (13120 ft.) or more.

The ECM operates the air pump heater relay which causes the air pump heater to operate.

These DTCs are designed to detect a malfunction in the air pump heater relay circuit. When the system is normal, the battery voltage is applied to terminal HAI1 of the ECM while the air pump heater relay is turned off, and the battery voltage is not applied to terminal HAI1 of the ECM while the air pump heater relay is turned on. The ECM illuminates the MIL and stores a DTC when either one of the following conditions is detected.

1. The battery voltage is not applied to terminal HAI1 while the air pump heater relay is off.
2. The battery voltage is applied to terminal HAI1 while the air pump heater relay is on.

This vehicle is equipped with a voltage inverter, which supplies power to various electrical appliances. When the main switch of the voltage inverter is turned ON, the inverter relay turns ON, and the inverter then converts the 12 V Direct Current (DC) of the battery into a 115 V Alternating Current (AC). The voltage inverter can output a maximum of 400 W from an outlet.

When the AC 115 V is output, a load is applied to the engine. The ECM controls the engine idling speed according to the vehicle speed and engine load. A speed signal is input to the inverter and an idle-up signal is transmitted to the ECM.

Scheme 391

While the engine is idling, the ECM performs idle up according to the power supply of the inverter to stabilize the engine idling speed.

When the vehicle is stationary and the inverter input exceeds 8.3 A, the inverter sends an idle-up signal from the OUT terminal of the inverter to the ELS3 terminal of the ECM.

If the idle-up signal is input into the ECM for 10 seconds while the vehicle is running, the ECM interprets this as a malfunction in the inverter circuit and stores the DTC.

P1603

After starting the engine, this DTC is stored when the engine stops without the ignition switch being operated.

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 has run out of fuel before performing troubleshooting, as this DTC is also stored when the engine stalls due to running out of fuel.

*1: for Automatic Transmission Models

P1605

This DTC is stored if the engine speed drops below the set speed without the ignition switch being operated.

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 idling is unstable due to running out of fuel.

*1: for Automatic Transmission Models

Scheme 392

Scheme 393

1. Reference waveforms showing a normal cold engine start
2. Reference waveforms showing a normal warm engine start
3. Reference values when there is an air leak in the intake system during rough idling FREEZE FRAME DATA P1605 ROUGH IDLING Parameter -3 -2 -1 0 1 Unit Engine Speed 671 474 525 427 390 RPM Calculate Load 45.0 44.3 45.0 45.4 45.0 % Vehicle Load 25.0 35.2 25.8 23.5 25.4 % MAF 4.51 4.51 4.48 3.65 2.70 gm/sec Atmosphere Pressure -0 -0 -0 -0 -0 psi(gauge) Coolant Temp 176 176 176 176 176 F Intake Air 91 91 91 91 91 F Battery Voltage 12.988 12.734 12.733 12.578 12.519 V Throttle Sensor Volt % 15.6 18.0 15.6 17.2 16.4 % Throttle Sensor #2 Volt % 47.4 50.1 47.4 49.4 47.4 % Throttle Sensor Position 0.0 0.0 0.0 0.0 0.0 % Throttle Motor DUTY 15.2 18.0 15.2 17.6 18.4 % Injector (Port) 4840 4759 4870 5262 5262 μs Injection Volume (Cylinder 1) 0.247 0.247 0.247 0.247 0.247 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 0.900 0.908 0.880 0.870 0.870 AF Lambda B1S1 1.232 1.232 1.232 1.232 1.232 AFS Voltage B1S1 4.996 4.996 4.996 4.996 4.996 V O2S B1 S2 0.115 0.115 0.115 0.835 0.835 V Short FT #1 0.000 0.000 0.000 0.000 0.000 % Long FT #1 2.344 2.344 2.344 2.344 2.344 % Total FT #1 0.020 0.020 0.020 0.020 0.020 Fuel System Status #1 OL Drive OL Drive OL Drive OL Drive OL Drive IGN Advance 4.5 11.5 9.5 4.5 4.5 deg Knock Feedback Value -3.0 -3.0 -3.0 -3.0 -3.0 deg(CA) Knock Correct Learn Value 15.5 15.5 15.5 15.5 15.5 deg(CA) VVT Control Status #1 ON ON ON ON ON Starter Signal OFF OFF OFF OFF OFF

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.

1. *1: for Automatic Transmission Models
2. *2: for Manual Transmission Models

Scheme 394

1. Reference waveforms showing a normal cold engine start
2. Reference waveforms showing a normal warm engine start
3. 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 1010 746 319 180 125 RPM Calculate Load 78.8 41.9 42.7 84.3 84.3 % Vehicle Load 9.4 21.1 28.7 20.3 26.2 % MAF 2.62 4.21 2.45 1.00 0.89 gm/sec Atmosphere Pressure -0 -0 -0 -0 -0 psi(gauge) Coolant Temp 183 183 183 183 183 F Intake Air 111 109 108 106 106 F Battery Voltage 11.269 11.914 11.835 11.855 11.875 V Throttle Sensor Volt % 16.4 16.8 16.4 16.4 16.4 % Throttle Sensor #2 Volt % 48.2 48.6 48.2 48.2 48.2 % Throttle Sensor Position 0.0 0.0 0.0 0.3 0.0 % Throttle Motor DUTY 16.8 16.4 16.4 16.4 16.4 % Injector (Port) 13560 4417 4081 4081 4081 μs Injection Volume (Cylinder 1) 0.130 0.130 0.246 0.246 0.246 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 0.954 0.954 0.870 0.870 0.876 AF Lambda B1S1 0.998 0.998 0.998 0.998 0.998 AFS Voltage B1S1 3.289 3.290 3.290 3.290 3.290 V O2S B1 S2 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 -3.907 -2.344 -2.344 -2.344 -2.344 % Total FT #1 -0.047 -0.047 -0.047 -0.047 -0.047 Fuel System Status #1 OL OL OL OL OL IGN Advance 5.0 8.0 7.0 5.0 5.0 deg Knock Feedback Value -3.0 -3.0 -3.0 -3.0 -3.0 deg(CA) Knock Correct Learn Value 15.5 15.5 15.5 15.5 15.5 deg(CA) VVT Control Status #1 OFF OFF OFF OFF OFF Starter Signal ON OFF OFF OFF OFF

The ECM continuously monitors its main and sub CPUs. This self-check ensures that the ECM is functioning properly. If outputs from the CPUs are different and deviate from the standard, the ECM will illuminate the MIL and store this DTC immediately.

See also:
• REMOVAL
• ON-VEHICLE INSPECTION - Step 4
• ON-VEHICLE INSPECTION - Step 1
• REMOVAL
• ON-VEHICLE INSPECTION
• INSPECTION
• ON-VEHICLE INSPECTION
• ON-VEHICLE INSPECTION - Step 2
• ON-VEHICLE INSPECTION - Step 11