Engine Control (Sfi) System (Diagnostic Codes (P0420-U0296) & Circuit Tests): Overview Lexus GS III рестайлинг

MONITOR DESCRIPTION

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air- fuel ratio control, rather than the conventional detecting method, which uses the locus ratio.

The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.

The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it illuminates the MIL and sets a DTC.

HINT

1. Bank 1 refers to the bank that includes the No. 1 cylinder.
2. Bank 2 refers to the bank that does not include the No. 1 cylinder.
3. Sensor 1 refers to the sensor closest to the engine assembly.
4. Sensor 2 refers to the sensor farthest away from the engine assembly.

DESCRIPTION

Refer to the EVAP System. Refer to DESCRIPTION .

In Sequence B and E, the leak detection pump creates negative pressure (vacuum) through the reference orifice. The EVAP system pressure is then measured by the ECM, using the canister pressure sensor, to determine the reference pressure. If the pressure is one of the following conditions, the ECM illuminates the MIL and sets the DTC (2 trip detection logic).

Scheme 38

1. Canister pressure is lower than the malfunction criterion (ex. 724 mmHg).
2. Canister pressure is higher than the malfunction criterion (ex. 752 mmHg).
3. Canister pressure is not saturated within 60 seconds.
4. Canister pressure difference of sequence B and sequence E is large.

Refer to the EVAP System. Refer to DESCRIPTION .

The two monitors, Key-Off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The Key-Off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the power switch is turned off. The purge flow monitor runs while the engine is running.

HINT

*: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the power 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 power switch is turned off, the monitor check starts 2.5 hours later.

Scheme 39

Scheme 40

1. KEY-OFF MONITOR Purge VSV stuck open In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system. The EVAP system pressure is then measured by the ECM using the canister pressure sensor. If the stabilized system pressure is higher than [second reference pressure x 0.2], the ECM interprets this as the purge VSV (Vacuum Switching Valve) being stuck open. The ECM illuminates the MIL and sets the DTC (2 trip detection logic). Purge VSV stuck closed In operation D, the canister pressure sensor measures the EVAP system pressure. The pressure measurement for purge VSV monitor is begun when the purge VSV is turned ON (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa-g (2.25 mmHg-g) or more, the purge VSV is functioning normally. If the pressure does not increase, the ECM interprets this as the purge VSV being stuck closed. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
2. PURGE FLOW MONITOR The purge flow monitor consists of the two step monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary.

1. The 1st monitor While the engine is running and the purge VSV (Vacuum Switching Valve) is on (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.
2. The 2nd monitor The vent valve is turned on (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.5 kPa (3.75 mmHg), the ECM interprets this as the Purge VSV being stuck closed. The ECM illuminates the MIL and sets DTC P0441 (2 trip detection logic).

Atmospheric pressure check

In order to ensure reliable malfunction detection, the variation between the atmospheric pressure, before and after conduction of the purge flow monitor is measured by the ECM.

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

Scheme 41

1. DTC P0450: Canister pressure sensor abnormal voltage fluctuation If the canister pressure sensor voltage output [pressure] rapidly fluctuates between less than 0.45 V [42.1 kPa-a (315.9 mmHg-a)] and more than 4.9 V [123.8 kPa-a (928.4 mmHg-a)], the ECM interprets this as an open or short circuit malfunction in the canister pressure sensor or its circuit, and stops the EVAP (Evaporative Emission) system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).
2. DTC P0451: Canister pressure sensor abnormal voltage fluctuation or being constant 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 sets the DTC. Alternatively, if the sensor voltage output does not change for 10 seconds, the ECM interprets this as the sensor being fixed/flat, and stops the monitor. The ECM then illuminates the MIL and sets the DTC. (Both the malfunctions are detected by 2 trip detection logic).
3. DTC P0452: Canister pressure sensor voltage low If the canister pressure sensor voltage output [pressure] is below 0.45 V [42.1 kPa-a (315.9 mmHg-a)], 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 sets the DTC (1 trip detection logic).
4. DTC P0453: Canister pressure sensor voltage high If the canister pressure sensor voltage output [pressure] is 4.9 V [123.8 kPa-a (928.4 mmHg-a)] 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 sets the DTC (1 trip detection logic).

The idle speed is controlled by the Electronic Throttle Control System (ETCS). The ETCS is comprised of: 1) 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; 5) the ECM, which controls the ETCS. Based on the target idle 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 (ISC). The ECM determines that the ISC system is malfunctioning if the following conditions are met

Scheme 42

1. The learned idling air flow volume remains at the maximum or minimum volume 5 seconds or more during a drive cycle.
2. After driving at a vehicle speed of 6.25 mph (10 km/h) or more, the actual engine idling speed varies from the target idling speed by more than -100 rpm or 150 rpm or more when the A/C off, or more than -100 rpm or 200 rpm or more when the A/C on, 5 times or more during a driving cycle, the ECM illuminates the MIL and sets the DTC.

This monitor will run when the engine is started at -10 to 50°C (14 to 122°F) of the engine coolant temperature. The DTC will set after the engine idling 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 at lower than 50°C (122°F) of the engine coolant temperature, the ECM measures the accumulated mass air flow at the 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 set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The ETCS (Electrical Throttle Control System) controls the idle speed. The ETCS 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 negative battery terminal is disconnected during inspection or repairs, the ISC (Idle Speed Control) learned values are cleared. ISC learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the ISC learned values cleared.

Scheme 43

This monitor will run when the engine is started at -10 to 50°C (14 to 122°F) of the engine coolant temperature. The DTC will set after the engine idling for 3 seconds (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started at lower than 50°C (122°F) of the engine coolant temperature, the ECM measures the accumulated mass air flow at the 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 set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The ETCS (Electrical Throttle Control System) controls the idle speed. The ETCS 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 negative battery terminal is disconnected during inspection or repairs, the ISC (Idle Speed Control) learned values are cleared. ISC learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the ISC learned values cleared.

Scheme 44

The battery supplies electricity to the ECM even when the power 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 memory 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 sets the DTC.

HINT

If DTC P0560 is set, the ECM does not store other DTCs or the data stored in the ECM are partly erased.

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM sets the appropriate DTC and illuminates the MIL.

The ECM memory status is diagnosed by internal mirroring of the main CPU and the sub CPU to detect Random Access Memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and sets a DTC if: 1) outputs from the two CPUs are different or deviate from the standards, 2) the signals sent to the throttle actuator deviate from the standards, 3) a malfunction is found in the throttle actuator supply voltage, and 4) any other ECM malfunction is found.

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

Note. First check for an exhaust gas leak around the heated oxygen sensor if P0606 is present. An exhaust gas leak generates noise in the heated oxygen sensor output. The ECM may interpret this as a heated oxygen sensor transistor malfunction.

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 standards, the ECM will illuminate the MIL and set a DTC immediately.

The ECM monitors the output voltage to the throttle actuator. This self-check ensures that the ECM is functioning properly. The output voltage is usually 0 V when the ignition switch is turned off. If the output voltage is higher than 7 volts when the power switch is turned off, the ECM will illuminate the MIL and set a DTC when the power switch on (IG).

The high pressure side fuel pump is attached to the insulator, which is attached to the cylinder head cover. The pump activates according to the position of the cam on the exhaust side camshaft (right bank).

The high pressure side fuel pump increases the pressure of the fuel supplied from the fuel pump in the fuel tank to 4 to 13 MPa (40.8 to 132.6 kgf/cm 2 , 580 to 1885 psi) according to the operating condition, and it feeds the fuel to the fuel delivery pipe.

The D-4S system has two injection systems. One is the in-cylinder direct injection system that directly injects pressurized fuel into the combustion chamber. The other is the intake port injection system. The ECM determines the percentage of in-cylinder direct injection to the intake port injection systems in accordance with the engine speed and load.

The ECM monitors the injection control of the port injector. If a malfunction is detected in the port injector circuit, the ECM cancels the injection control for the corresponding cylinder and turns on the Malfunction Indicator Lamp (MIL).

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

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

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

Scheme 45

1. P1451: Pressure sensor abnormal voltage fluctuation or being constant If the pressure sensor output voltage fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as the pressure sensor voltage fluctuating, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC. Alternatively, if the sensor output voltage does not change for 10 seconds, the ECM interprets this as the sensor voltage being constant, and stops the monitor. The ECM then illuminates the MIL and sets the DTC. (Both the malfunctions are detected by 2 trip detection logic).
2. P1452: Pressure sensor voltage low If the pressure sensor output voltage is below 0.45 V, the ECM interprets this as an open or short circuit malfunction in the pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).
3. P1453: Pressure sensor voltage high If the pressure sensor voltage output is 4.9 V or more, the ECM interprets this as an open or short circuit malfunction in the pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and sets the DTC (1 trip detection logic).

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

The opening angle of the throttle valve is detected by the Throttle Position (TP) sensor, which is mounted on the throttle body. The TP sensor provides feedback to the ECM. This feedback allows the ECM to appropriately control the throttle actuator and monitor the throttle opening angle as the ECM responds to driver inputs.

HINT

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

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 sets a DTC.

1. Example: When the electrical current is more than 10 A, or 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 sets a DTC. If the malfunction is not repaired successfully, a DTC is set when the engine is quickly revved to a high rpm several times after the engine has idled for 5 seconds after engine start.

SYSTEM DESCRIPTION

The throttle actuator is operated by the ECM, and opens and closes the throttle valve using gears. The opening angle of the throttle valve is detected by the Throttle Position (TP) sensor, which is mounted on the throttle body. The TP sensor provides feedback to the ECM. This feedback allows the ECM to appropriately control the throttle actuator and monitor the throttle opening angle as the ECM responds to driver inputs.

HINT

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

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 sets a DTC.

If the malfunction is not repaired successfully, a DTC is set when the accelerator pedal is fully depressed and released quickly (to fully open and close the throttle valve) after the engine is next started.

The ETCS (Electronic Throttle Control System) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (less than 4 V), the ECM determines that there is a malfunction in the ETCS and cuts off the current to the throttle actuator.

When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the throttle actuator is cut. If repairs are made and the system returns to normal, turn the power 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 46

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 sets the DTC.

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

The Electronic Throttle Control System (ETCS) consists of a throttle actuator, Throttle Position (TP) sensor, hybrid vehicle control ECU and ECM. The ECM operates the throttle actuator to control the throttle valve angle based on requests from the hybrid vehicle control ECU. The TP sensor detects the throttle valve angle and provides feedback to the ECM, which then adjusts the throttle valve to the appropriate angle.

The ECM determines the actual opening angle of the throttle valve from the TP sensor signal. The actual opening angle is compared to the target opening angle commanded by the ECM. If the difference between these two values is outside the standard range, the ECM interprets this as a malfunction in the ETCS. The ECM then illuminates the MIL and sets the DTC.

HINT

1. Although the DTC titles include oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
2. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is 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 narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte though 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 TWC is used. For the most efficient use of the TWC, 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 A/F sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

Scheme 47

HINT

1. DTCs P2195 and P2196 indicate malfunctions related to the bank 1 A/F sensor circuit.
2. DTCs P2197 and P2198 indicate malfunctions related to the bank 2 A/F sensor circuit.
3. Bank 1 refers to the bank that includes the No. 1 cylinder.
4. Bank 2 refers to the bank that includes the No. 2 cylinder.
5. When any of these DTCs are set, check the A/F sensor output voltage by entering the following menus on the Techstream: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1 or AFS Voltage B2S1.
6. Short-term fuel trim values can also be read using the Techstream.
7. The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM to a constant level. Therefore, the A/F sensor output voltage cannot be confirmed without using the Techstream.
8. If an A/F sensor malfunction is detected, the ECM sets a DTC.

Sensor voltage detection monitor

Under the air-fuel ratio feedback control, if the A/F sensor output voltage indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL and sets a DTC.

Example

If the A/F sensor output voltage is less than 2.8 V (very rich condition) for 15 seconds, despite the rear HO2 sensor output voltage being less than 0.6 V, the ECM sets DTC P2196. Alternatively, if the A/F sensor output voltage is more than 3.8 V (very lean condition) for 15 seconds, despite the rear HO2 sensor output voltage being 0.15 V or more, DTC P2195 is set.

Sensor current detection monitor

A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the A/F sensor current during fuel-cut and detects any abnormal current values.

If the A/F sensor output is 3.6 mA or more for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the A/F sensor and sets DTC P2195 (high-side stuck). If the A/F sensor output is less than 1.0 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 (low-side stuck).

Scheme 48

HINT

1. Although the DTC titles include the oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
2. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is 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 narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte though 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 TWC is used. For the most efficient use of the TWC, 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 A/F sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

HINT

1. DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 A/F sensor circuit.
2. DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 A/F sensor circuit.
3. Bank 1 refers to the bank that includes the No. 1 cylinder.
4. Bank 2 refers to the bank that includes the No. 2 cylinder.

The Air-Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. If the A/F sensor impedance (alternating current resistance) or output voltage deviates greatly from the standard range, the ECM determines that there is an open or short malfunction in the A/F sensor circuit.

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

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 sets the DTC.

Scheme 49

Refer to the EVAP System. Refer to DESCRIPTION .

To ensure the accuracy of the EVAP (Evaporative Emission) monitor values, the soak timer, which is built into the ECM, measures 5 hours (+-15 minutes) from when the power switch is turned off before the monitor begins to run. This allows the fuel to cool down, which stabilizes the Fuel Tank Pressure (FTP). When 5 hours have elapsed, the ECM turns on.

Scheme 50

5 hours after the power switch is turned off, the soak timer activates the ECM to begin the EVAP system monitor. 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. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).

HINT

1. DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.
2. DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.
3. Bank 1 refers to the bank that includes the No. 1 cylinder.
4. Bank 2 refers to the bank that includes the No. 2 cylinder.
5. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
6. Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
7. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is 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 narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte though 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 TWC is used. For the most efficient use of the TWC, 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 A/F sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

After the engine is warmed up, the ECM performs air-fuel ratio feedback control to maintain the air-fuel ratio at the stoichiometric level. In addition, active A/F ratio control is performed for approximately 10 seconds after preconditions are met in order to measure the A/F sensor response rate. During active A/F ratio control, the ECM forcibly increases and decreases the injection volume a certain amount, based on the stoichiometric air-fuel ratio learned during normal air-fuel ratio control, and measures the A/F sensor response rate. The ECM receives a signal from the A/F sensor while performing active A/F ratio control and uses it to calculate the A/F sensor response rate deterioration level.

If the value for A/F sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and sets the DTC.

Scheme 51

From the hybrid vehicle control ECU, the ECM receives data such as power output required for the engine (required output), estimated torque produced by the engine (estimated torque), engine RPM of control target (target RPM), and whether the engine is in start mode or not. Then, based on the required output and target RPM, the ECM calculates a target torque that is to be produced by the engine and compares it with the estimated torque. If the estimated torque is very low compared with the target torque, or the engine start mode continues for the specific duration calculated by water temperature, an abnormal condition is detected.

The ECM and hybrid vehicle control ECU are connected by a communication line called CAN. The ECM sends engine speed data and other data to the hybrid vehicle control ECU while the hybrid vehicle control ECU sends the information such as a requirement for the engine power to the ECM using the CAN communication line. When the communication between the ECM and hybrid vehicle control ECU is normal and the following items become a specified condition, the ECM illuminates the MIL and sets a DTC.

1. Engine speed
2. Power switch
3. Target torque
4. Ratio of target torque against estimated torque
5. Fuel level

The ECM intercommunicates with the hybrid vehicle control ECU through the Controller Area Network (CAN).

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

The Controller Area Network (CAN) is a serial data communication system for real-time application. It is a multiplex communication system designed for on-vehicle use that provides a superior communication speed of 500 kbps and a capability to detect malfunctions. Through the combination of the CANH and CANL bus lines, the CAN is able to maintain communication based on differential voltage.

While the engine is running, if a predetermined condition (closed loop, etc.) is met, the purge VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM will change the duty cycle ratio of the purge VSV to control purge flow volume.

Purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that purge flow is maintained when negative pressure (vacuum) is applied to the canister.

The ECM monitors the condition of both the key-off monitor and purge flow monitor to ensure proper operation of the EVAP system.

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Key-off monitor

This monitoring system checks for canister pump module malfunctions and leaks from the EVAP and closed tank systems. Be sure to leave the vehicle for at least 5 hours to sufficiently cool the fuel and stabilize fuel tank pressure. This makes EVAP system monitoring more accurate.

HINT

If the engine coolant temperature is 35°C (95°F) or more, 5 hours after the power switch has been turned off, the ECM will begin performing a monitor check after another 2 hours. If the engine coolant temperature is still 35°C (95°F) or more, 7 hours after the power switch has been turned off, the ECM will begin performing a monitor check after another 2.5 hours.

There are two methods for monitoring the EVAP system.

1. If the fuel tank pressure is higher or lower than the atmospheric pressure, the system determines that there are no leaks in the closed tank system and the system will check for leaks from the piping and canister between the purge VSV and canister pump module. (Method A)
2. If the fuel tank pressure is almost the same as the atmospheric pressure, vacuum pressure will enter the fuel tank and the system will check for leaks from the fuel tank after checking for leaks from the canister. (Method B)

Scheme 57

HINT

*: If there is only a small amount of fuel in the fuel tank, stabilizing the EVAP pressure takes longer than usual.

Scheme 58

Purge flow monitor

If EVAP system pressure change is less than 7.5 mmHg (1 kPa) when the engine is running and the purge VSV is turned on (closed), the ECM determines that the purge flow is insufficient.

Scheme 59

When the power switch is turned on (IG), the battery voltage is applied to the IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the integration relay (EFI MAIN relay) and supplying power to either terminal +B or +B1 of the ECM.

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1. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - BODY GROUND) Remove the integration relay from the engine room No. 1 junction block. Measure the voltage between the terminal of the wire harness side connector and body ground. Standard voltage Tester Connection Specified Condition Engine room No. 1 junction block (1R-1) - Body ground 9 to 14 V Reinstall the integration relay. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - BATTERY) OK: Go to next step
2. INSPECT INTEGRATION NO. 1 RELAY (EFI MAIN RELAY) Remove the integration relay (Unit A) from the engine room No. 1 junction block. Inspect the EFI fuse. Remove the EFI fuse from the integration relay. Measure the resistance of the EFI fuse. Standard resistance Below 1 ohms Reinstall the EFI fuse. Inspect the EFI MAIN relay. Measure the resistance of the EFI MAIN relay. Standard resistance Tester Connection Specified Condition 1R-1 - 1T-8 10 kohms or higher Below 1 ohms (Apply battery voltage between terminals 1T-6 and 1T-7) Reinstall the integration relay. NG --> REPLACE INTEGRATION NO. 1 RELAY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (+B, +B1 AND MREL CIRCUIT) Check the harness and the connectors between the integration relay and the ECM. Remove the integration relay (Unit A) from the engine room No. 1 junction block. Disconnect the A53 ECM connector. Measure the resistance between the terminals of the wire harness side connectors. Standard resistance (Check for open) Tester Connection Specified Condition MREL (A53-12) - Engine room No. 1 junction block (1T-6) Below 1 ohms +B (A53-2) - Engine room No. 1 junction block (1T-8) +B1 (A53-1) - Engine room No. 1 junction block (1T-8) Standard resistance (Check for short) Tester Connection Specified Condition MREL (A53-12) or Engine room No. 1 junction block (1T-6) - Body ground 10 kohms or higher +B (A53-2) or Engine room No. 1 junction block (1T-8) - Body ground +B1 (A53-1) or Engine room No. 1 junction block (1T-8) - Body ground Check the harness and the connectors between the integration relay and body ground. Measure the resistance between the terminals of the wire harness side connector and body ground. Standard resistance (Check for open) Tester Connection Specified Condition Engine room No. 1 junction block (1T-7) - Body ground Below 1 ohms Reinstall the integration relay. Reconnect the ECM connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Disconnect the E83 ECM connector. Measure the resistance. Standard resistance (Check for open) Tester Connection Specified Condition E1 (E83-104) - Body ground Below 1 ohms Reconnect the ECM connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. INSPECT ECM (IGSW VOLTAGE) Disconnect the E83 and A53 ECM connectors. Turn the power switch on (IG). Measure the voltage between the terminals of the ECM connectors. Standard voltage Tester Connection Specified Condition IGSW (A53-11) - E1 (E83-104) 9 to 14 V Reconnect the ECM connectors. OK --> REPLACE ECM NG: Go to next step
6. INSPECT FUSE (IGN AND IG2 MAIN FUSE) Remove the IGN fuse from the main body ECU (cowl side junction block RH). Remove the IG2 MAIN fuse from the engine room No. 1 relay block. Measure the resistance of the IGN and IG2 MAIN fuse. Standard resistance Below 1 ohms NG --> CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE OK: Go to next step
7. INSPECT IG2 RELAY Remove the IG2 relay from the engine room No. 1 relay block. Measure the resistance of the IG2 relay. Standard resistance Tester Connection Specified Condition 3 - 5 10 kohms or higher 3 - 5 Below 1 ohms (When battery voltage applied to terminals 1 and 2) Reinstall the relay. NG --> REPLACE IG2 RELAY OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY) Remove the IG2 relay from the engine room No. 1 relay block. Disconnect the A53 ECM connector. Measure the resistance between the terminal of the wire harness side connectors. Standard resistance (Check for open) Tester Connection Specified Condition Relay block IG2 relay terminal (3) - IGSW (A53-11) Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition Relay block IG2 relay terminal (3) or IGSW (A53-11) - Body ground 10 Kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - POWER SOURCE CONTROL ECU) Remove the IG2 relay from the engine room No. 1 relay block. Disconnect the K73 power source control ECU connector. Measure the resistance between the terminal of the wire harness side connectors. Standard resistance (Check for open) Tester Connection Specified Condition Relay block IG2 relay terminal (2) - IG2D (K73-35) Below 1 ohms Relay block IG2 relay terminal (1) - Body ground Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition IG2D (K73-35) - Body ground 10 kohms or higher OK --> CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR

The ECM constantly generates 5 V power 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 71

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.

HINT

Under normal conditions, the MIL is illuminated for several seconds when the power switch is first turned on (IG). The MIL goes off when the engine is started.

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1. CHECK MIL CONDITION Check that the Malfunction Indicator Lamp (MIL) lights up when turning the power switch on (IG). OK MIL illuminates OK --> SYSTEM OK NG: Go to next step
2. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM Connect the Techstream to the DLC3. Turn the power switch on (IG) and Techstream on. Check the communication between the Techstream and ECM. Result Result Proceed to Communication is possible A Communication is not possible B A --> GO TO MIL CIRCUIT B: Go to next step
3. CHECK MIL (THROTTLE POSITION SENSOR) Disconnect the E39 throttle body connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the throttle body connector. A --> REPLACE THROTTLE BODY B: Go to next step
4. CHECK MIL (VVT SENSOR FOR INTAKE CAMSHAFT BANK 1) Disconnect the E50 VVT sensor for intake camshaft (bank 1) connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the VVT sensor for intake camshaft (bank 1) connector. A --> REPLACE VVT SENSOR B: Go to next step
5. CHECK MIL (VVT SENSOR FOR EXHAUST CAMSHAFT BANK 1) Disconnect the E58 VVT sensor for exhaust camshaft (bank 1) connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the VVT sensor for exhaust camshaft (bank 1) connector. A --> REPLACE VVT SENSOR B: Go to next step
6. CHECK MIL (VVT SENSOR FOR INTAKE CAMSHAFT BANK 2) Disconnect the E60 VVT sensor for intake camshaft (bank 2) connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the VVT sensor for intake camshaft (bank 2) connector. A --> REPLACE VVT SENSOR B: Go to next step
7. CHECK MIL (VVT SENSOR FOR EXHAUST CAMSHAFT BANK 2) Disconnect the E66 VVT sensor for exhaust camshaft (bank 2) connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the VVT sensor for exhaust camshaft (bank 2) connector. A --> REPLACE VVT SENSOR B: Go to next step
8. CHECK MIL (CANISTER PUMP MODULE) Disconnect the canister pump module connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the canister pump module connector. A --> REPLACE CANISTER B: Go to next step
9. CHECK MIL (FUEL TANK PRESSURE SENSOR) Disconnect the e1 fuel tank pressure sensor connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the fuel tank pressure sensor connector. A --> REPLACE FUEL TANK PRESSURE SENSOR B: Go to next step
10. CHECK MIL (FUEL PRESSURE SENSOR) Disconnect the E72 fuel pressure sensor connector. Turn the power switch on (IG). Check the MIL. Result Result Proceed to MIL illuminates A MIL does not illuminate B Reconnect the fuel pressure sensor connector. A --> REPLACE FUEL PRESSURE SENSOR B: Go to next step
11. CHECK HARNESS AND CONNECTOR Disconnect the E39 throttle body connector. Disconnect the E50 VVT sensor for intake camshaft (bank 1) connector. Disconnect the E58 VVT sensor for exhaust camshaft (bank 1) connector. Disconnect the E60 VVT sensor for intake camshaft (bank 2) connector. Disconnect the E66 VVT sensor for exhaust camshaft (bank 2) connector. Disconnect the V17 or x1 canister pump module connector. Disconnect the e1 fuel tank pressure sensor connector. Disconnect the E72 fuel pressure sensor connector. Disconnect the E83 ECM connectors. Measure the resistance. Standard resistance (check for short) Tester Connection Specified Condition VC (E83-125) - Body ground 10 kohms or higher VC2 (E83-120) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE ECM

Based on vehicle driving conditions, the ECM operates the fuel pump. The ECM receives an engine start request signal from the hybrid vehicle control ECU. When the engine is cranked, an NE signal is sent to the ECM. When the engine is started, the ECM connects the FC circuit to the body ground, operates the C/OPN (circuit opening) relay, and operates the fuel pump.

The fuel pump's has a high and low speed setting. When the engine is starting or operating with a heavy load, the ECM's Tr2 turns off, the F/PMP relay turns on, and the fuel pump operates at the high speed setting. When the engine is idling or operating with a light load, the Tr2 turns off, current flows through the fuel pump resistor to the fuel pump, and the fuel pump operates at the low speed setting.

When the ECM receives an engine stop request signal from the hybrid vehicle control ECU, or when fuel cut occurs as a result of vehicle deceleration, etc., the fuel pump is stopped.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PUMP/SPD) Connect the Techstream to the DLC3. Turn the power switch on (IG) and turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed. Check whether the fuel pump operating sound occurs when perform the Active Test on the Techstream. OK Fuel pump operating sound occurs. OK --> See step 10 NG: Go to next step
2. INSPECT INTEGRATION NO. 1 RELAY Remove the integration relay (Unit A) from the engine room No. 1 junction block. Inspect the F/PMP fuse. Remove the F/PMP fuse from the integration relay. Measure the resistance of the F/PMP fuse. Standard resistance Below 1 ohms Reinstall the F/PMP fuse. Inspect the EFI NO. 2 and C/OPN relay. Measure the resistance of the EFI NO. 2 and C/OPN relays. Standard resistance: EFI NO. 2 RELAY Tester Connection Specified Condition 1R-1 - 1S-4 10 kohms or higher Below 1 ohms (Apply battery voltage between terminals 1T-8 and 1S-3) C/OPN RELAY Tester Connection Specified Condition 1R-1 - 1S-8 10 kohms or higher Below 1 ohms (Apply battery voltage between terminals 1T-8 and 1S-3, 1R-1 and 1S-7) Reinstall the integration relay. NG --> REPLACE INTEGRATION NO. 1 RELAY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, INTEGRATION RELAY - FUEL PUMP RESISTOR) Remove the integration relay (Unit A) from the engine room No. 1 junction block. Disconnect the A53 ECM connector. Disconnect the A45 fuel pump resistor connector. Measure the resistance. Standard resistance (Check for open) Tester Connection Specified Condition Engine room No. 1 junction block (1S-7) - FC (A53-7) Below 1 ohms Engine room No. 1 junction block (1S-8) - A45-1 Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition Engine room No. 1 junction block (1S-7) or FC (A53-7) - Body ground 10 kohms or higher Engine room No. 1 junction block (1S-8) or A45-1 - Body ground 10 kohms or higher Reinstall the integration relay. Reconnect the ECM connector. Reconnect the fuel pump resistor. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. INSPECT ECM POWER SOURCE CIRCUIT NG --> REPAIR OR REPLACE POWER SOURCE CIRCUIT COMPONENTS OK: Go to next step
5. INSPECT F/PMP RELAY Remove the F/PMP relay from the engine room No. 1 relay block. Measure the resistance of the F/PMP relay. Standard resistance Tester Connection Specified Condition 3 - 4 10 kohms or higher 3 - 4 Below 1 ohms (when battery voltage applied to terminals 1 and 2) NG --> REPLACE F/PMP RELAY OK: Go to next step
6. INSPECT FUEL PUMP RESISTOR Remove the fuel pump resistor. Measure the resistance of the fuel pump resistor. Standard resistance 0.30 to 0.34 ohms at 20°C (68°F) NG --> REPLACE FUEL PUMP RESISTOR OK: Go to next step
7. INSPECT FUEL PUMP FOR LOW PRESSURE SIDE Remove the rear seat cushion. Disconnect the V11 fuel pump connector. Inspect fuel pump resistance. Measure the resistance between terminals 4 and 5. Standard resistance 0.2 to 3.0 ohms at 20°C (68°F) Inspect fuel pump operation. Apply battery voltage to both the terminals. Check that the pump operates. NOTE: These tests must be done quickly (within 10 seconds) to prevent the coil from burning out. Keep the fuel pump as far away from the battery as possible. Always turn the voltage on and off on the battery side, not the fuel pump side. NG --> REPLACE FUEL PUMP FOR LOW PRESSURE SIDE OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (F/PMP RELAY - ECM, F/PMP RELAY - FUEL PUMP RESISTOR) Remove the F/PMP relay from the engine room No. 1 relay block. Disconnect the A53 ECM connector. Disconnect the A45 fuel pump resistor connector. Measure the resistance of the wire harness side connectors. Standard resistance (Check for open) Tester Connection Specified Condition F/PMP relay (2) - FPR (A53-6) Below 1 ohms F/PMP relay (1) - A45-1 Below 1 ohms F/PMP relay (3) - A45-1 Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition F/PMP relay (2) or FPR (A53-6) - Body ground 10 kohms or higher F/PMP relay (1) or A45-1 - Body ground 10 kohms or higher F/PMP relay (3) or A45-1 - Body ground 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. CHECK HARNESS AND CONNECTOR (F/PMP RELAY - FUEL PUMP, FUEL PUMP RESISTOR - FUEL PUMP, FUEL PUMP - BODY GROUND) Remove the F/PMP relay from the engine room No. 1 relay block. Disconnect the V11 fuel pump connector. Disconnect the A45 fuel pump resistor connector. Measure the resistance. Standard resistance (Check for open) Tester Connection Specified Condition F/PMP relay (4) - V11-4 Below 1 ohms A45-2 - V11-4 Below 1 ohms V11-5 - Body ground Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition F/PMP relay (4) or V11-4 - Body ground 10 kohms or higher A45-2 or V11-4 - Body ground 10 kohms or higher Reconnect the fuel pump resistor connector. Reconnect the fuel pump connector. Reinstall the F/PMP relay. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE ECM
10. READ VALUE USING TECHSTREAM (ENGINE SPEED) Connect the Techstream to the DLC3. Turn the power switch on (IG) and turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Data List / Engine Speed. Read the values displayed on the Techstream while cranking. OK Values are displayed continuously. NG --> REPAIR OR REPLACE CRANKSHAFT POSITION SENSOR OK --> REPLACE ECM

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM. When the power switch is turned on (IG), 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 power switch is turned on (IG), the MIL should illuminate. Then when the power switch is turned on (READY), the MIL should turn off. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.

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1. CHECK THAT MIL IS ILLUMINATED Perform troubleshooting in accordance with the table below. Result Condition Proceed to MIL remains ON A MIL does not illuminate B B --> See step 5 A: Go to next step
2. CHECK WHETHER MIL TURNS OFF Connect the Techstream to the DLC3. Turn the power switch on (IG) and turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes. Check if any DTCs have been stored. Note down any DTCs. Clear DTCs. Refer to «DTC CHECK / CLEAR»(ref-387083-S04846376252011022400000) . Check if the MIL goes off. OK MIL should go off. OK --> REPAIR CIRCUIT INDICATED BY OUTPUT DTC NG: Go to next step
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) Disconnect the A53 ECM connector. Turn the power switch on (IG). Check that the MIL is not illuminated. OK MIL is not illuminated. Reconnect the ECM connector. OK --> REPLACE ECM NG: Go to next step
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) Disconnect the K31 combination meter connector. Disconnect the A53 ECM connector. Measure the resistance. Standard resistance (Check for short) Tester Connection Specified Condition W (A53-24) or EFI (K31-8) - Body ground 10 kohms or higher Reconnect the combination meter connector. Reconnect the ECM connector. OK --> REPAIR OR REPLACE COMBINATION METER ASSEMBLY NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR
5. CHECK THAT MIL IS ILLUMINATED Check if the MIL is illuminated when the power switch is turned on (IG). OK MIL should be illuminated. OK --> SYSTEM OK NG: Go to next step
6. CHECK THAT ENGINE STARTS Turn the power switch on (IG). Start the engine. Result Result Proceed to Engine starts A Engine does not start* B HINT: *: The Techstream cannot communicate with the ECM. B --> GO TO VC OUTPUT CIRCUIT A: Go to next step
7. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT) Check the MIL circuit. Refer to «SYSTEM DIAGRAM»(ref-387092-S07682878112011022400000) . NG --> REPAIR OR REPLACE COMBINATION METER ASSEMBLY OK --> CHECK AND REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)

See also:
• COMPONENTS
• REMOVAL
• ON-VEHICLE INSPECTION
• ON-VEHICLE INSPECTION - Step 2