GENERAL DESCRIPTION
The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the exhaust camshaft. There is no variation in valve timing of the exhaust cam because the exhaust camshaft is driven by the timing belt. The timing of the intake cam is varied by the relative operation the CVVT vane to the housing. This system helps the engine decrease exhaust gases and increase engine power and fuel economy by changing the valve open/close timing of the intake camshaft.
DTC DESCRIPTION
The deviation of the camshaft position from the target point is evaluated during stable driving condition. The ECM accumulats this deviation for a certain period and sets DTC P0011 when the accumulated deviation is too high. The target camshaft position is predetermineded value depending on engine speed and throttle angle in the ECM.
The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the exhaust camshaft. There is no variation in valve timing of the exhaust cam because the exhaust camshaft is driven by the timing belt. The timing of the intake cam is varied by the relative operation the CVVT vane to the housing. This system helps the engine decrease exhaust gases and increase engine power and fuel economy by changing the valve open / close timing of the intake camshaft.
DTC P0016 is set when actual camshaft position is too much retarded or advanced than full retard position or full advance position. To continue the adjustment in such case could lead to a damage of the engine by hitting the valves with the piston.
The normal operating temperature of the HO2S(Heated Oxygen Sensor) ranges from 350 to 850°C (662 to 1562°F). The HO2S heater greatly decreases the amount of time required for fuel control to become active. The ECM provides a pulse width modulated control circuit to adjust current through the heater. When the HO2S is cold, the value of the resistance is low and the current in the circuit is high. On the contrary, if the temperature in the resistor of the sensor rises, the current drops gradually.
The ECM determines if a front HO2S heater fault has occurred and sets DTC P0030 if the front HO2S heater control driver inside the ECM fails, if HO2S is not operational (after an elapse of predetermined time) since engine start, or when the front HO2S tip temperature is out of normal working range.
Refer to DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 / SENSOR 1) .
ECM sets DTC P0031 if the ECM detects that the front HO2S heater control circuit is short to ground.
Refer to DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 / SENSOR 1) .
ECM sets DTC P0032 if the ECM detects that the front HO2S heater control line is open or short to battery circuit.
The normal operating temperature of the HO2S(Heated Oxygen Sensor) ranges from 350 to 850°C(662 to 1562°F). The HO2S heater greatly decreases the amount of time required for fuel control to become active. The ECM provides a pulse width modulated control circuit to adjust current through the heater. When the HO2S is cold, the value of the resistance is low and the current in the circuit is high. On the contrary, if the temperature in the resistor of the sensor rises, the current drops gradually.
The ECM determines when a rear HO2S heater fault occurs and sets DTC P0036 if measured rear HO2S resistance is lower than the predetermined threshold.
Refer to DTC P0036 HO2S HEATER CONTROL CIRCUIT (BANK 1 / SENSOR 2) .
ECM sets DTC P0037 if the ECM detects that the rear HO2S heater control line is short to ground.
Refer to DTC P0036 HO2S HEATER CONTROL CIRCUIT (BANK 1 / SENSOR 2) .
ECM sets DTC P0038 if the ECM detects that the rear HO2S heater control line is open or short to battery line.
The CVVT (Continuously Variable Valve Timing) system built on the camshaft helps the engine decrease the exhaust gas and increase engine power and fuel economy by changing the valve open/close timing of the intake camshaft continuously. The intake valve control solenoid, the main control part of the CVVT, changes the direction of the oil path through the CVVT by the duty control of the ECM and changes the open and close timing of the intake and exhaust valves.
ECM sets DTC P0076 if the ECM detects that the CVVT oil control valve control circuit is short to ground.
Refer to DTC P0076 INTAKE VALVE CONTROL SOLENOID CIRCUIT LOW (BANK 1) .
ECM sets DTC P0077 if the ECM detects that the OCV control circuit is open or short to battery.
The Mass Air Flow Sensor (MAFS) is located between the air cleaner assembly and the throttle body. The MAFS uses a hot film type sensing element to measure the mass of intake air entering the engine. This hot film type air flow sensor consists of a hot film sensor, housing and metering ducts. Mass air flow rate is measured by detection of heat transfer from a hot film probe. The change in air flow rate causes change in the amount of heat being transferred from the hot film probe surface to the air. A large amount of intake air represents acceleration or high load conditions while a small amount of intake air represents deceleration or idle. The mass of intake air should increase at acceleration and be stable during constant engine speed. The ECM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
The ECM compares the actual measured Mass Air Flow signal to the modeled Mass Air Flow value and sets the DTC P0101 when the difference between these two value is too high or too low with lambda deviation in opposite direction. The ECM illuminates the MIL on the second consecutive driving cycle that the diagnostic runs and fails.
The modeled Mass Air Flow value is determined by engine speed, throttle angle and ICA duty.
Scheme 30
Refer to DTC P0101 MASS OR VOLUME AIR FLOW CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0102 if the ECM detects signal voltage lower than the possible range of a properly operating MAF sensor.
Scheme 31
Refer to DTC P0101 MASS OR VOLUME AIR FLOW CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0103 if the ECM detects signal voltage higher than the possible range of a properly operating MAF sensor.
Scheme 32
The Intake Air Temperature Sensor (IATS) is installed into the Mass Air Flow Sensor (MAFS). The IATS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the IATS decreases as the temperature increases, and increases as the temperature decreases. The 5 V power source in the ECM is supplied to the IATS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the IATS are connected in series. When the resistance value of the thermistor in IATS changes according to the intake air temperature, the signal voltage also changes. Using this signal, the information of the intake air temperature, the ECM corrects basic fuel injection duration and ignition timing.
The purpose of this diagnosis is to detect a stuck intake air temperature signal. The diagnostic function checks whether after a variation of the calculated intake air temperature also a variation of the measured intake air temperature is detected. ECM sets DTC P0111 when the variation of measured intake air temperature from engine start is smaller than threshold while variation of calculated intake air temperature by ECM is greater than threshold.
Refer to DTC P0111 INTAKE AIR TEMPERATURE SENSOR1 CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0112 if the ECM detects signal voltage lower than the possible range of a properly operating IATS.
Refer to DTC P0111 INTAKE AIR TEMPERATURE SENSOR1 CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0113 if the ECM detects signal voltage higher than the possible range of a properly operating IATS.
The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5 V in the ECM is supplied to the ECTS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the ECTS are connected in series. When the resistance value of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. During cold engine operation the ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve drivability.
The purpose of this diagnosis is to detect a stuck coolant temperature signal. ECM sets DTC P0116 when the variation of measured engine coolant temperature from engine start is smaller than threshold while variation of calculated coolant temperature by ECM is greater than threshold.
Refer to DTC P0116 ENGINE COOLANT TEMPERATURE CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0117 if the ECM detects signal voltage lower than the possible range of a properly operating ECTS.
Refer to DTC P0116 ENGINE COOLANT TEMPERATURE CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0118 if the ECM detects signal voltage higher than the possible range of a properly operating ECTS.
The Throttle Position Sensor (TPS) is mounted on the throttle body and detects the opening angle of the throttle plate. The TPS has a variable resistor (potentiometer) whose characteristic is the resistance changing according to the throttle angle. During acceleration, the TPS resistance between the reference 5V and the signal terminal decreases and output voltage increases; during deceleration, the TPS resistance increases and TPS output voltage decreases. The ECM supplies a reference 5V to the TPS and the output voltage increases directly with the opening of the throttle valve. The TPS output voltage will vary from 0.2~0.8V at closed throttle to 4.3~4.8V at wide-open throttle. The ECM determines operating conditions such as idle (closed throttle), part load, acceleration/deceleration, and wide-open throttle from the TPS. Also The ECM uses the Mass Air Flow Sensor (MAFS) signal along with the TPS signal to adjust fuel injection duration and ignition timing.
The ECM compares the actual measured Mass Air Flow signal with the modeled Mass Air Flow value to detect implausible TPS signal. Because throttle position is one of key parameters in determining the modeled MAF. The modeled Mass Air Flow value is determined by engine speed, throttle angle and ISCA duty. The DTC P0121 is set when the difference between these two value is too high or too low with lambda deviation in same direction for a certain time.
Scheme 33
Refer to DTC P0121 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0122 if the ECM detects signal voltage lower than the possible range of a properly operating TPS.
Refer to DTC P0121 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT RANGE/PERFORMANCE .
ECM sets DTC P0123 if the ECM detects signal voltage higher than the possible range of a properly operating TPS.
Scheme 34
An Engine Coolant Temperature Sensor (ECTS) monitors the temperature of the coolant. This input is used by the ECM for engine control and as an enabling criteria for related diagnostics. The air flow coming into the engine is accumulated and used to determine if the engine has been driven within conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not reach regulating temperature of the thermostat, diagnostics that use engine coolant temperature as enabling criteria, may not run when expected. This DTC will set when there has been excessive time to reach a minimum coolant temperature required for closed loop fuel control.
The purpose of this diagnosis is to monitor the minimum coolant temperature that enables lambda closed loop control after start. Minimum coolant temperature to run lambda control must be reached before the threshold time predetermined according to intake air temperature at start. If the lambda control is not active because of low engine coolant temperature within predetermined minimum time after start, the ECM sets DTC P0125.
Refer to DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL .
An open stuck thermostat means an increase of the engine warm up time and can cause emission increase as well. To detect open stuck thermostat, the ECM checks measured coolant temperature as soon as calculated coolant temperature reaches threshold and sets DTC P0128 when measured coolant temperature is lower than threshold. If same code is set again in the next driving cycle, MIL is illuminated.
The HO2S is used to supply the ECM with information regarding the composition of the air/fuel mixture. The HO2S is positioned in the exhaust pipe ahead of the TWC. To measure the oxygen content, the HO2S requires a supply of ambient air as a reference. Since this is supplied through the wiring, the lead must not be clamped or damaged in any other way. The HO2S produces a voltage that varies between 0.1V and 0.9V under normal operating conditions. The Engine Control Module (ECM) monitors this voltage and determines if the exhaust gas is lean or rich. If the voltage input at the ECM is under approx. 0.45V the exhaust is lean, and if the voltage input is over approx. 0.45V the exhaust is rich. The ECM constantly monitors the HO2S signal during closed loop operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary.
ECM sets DTC P0130 if the ECM detects that the front HO2S signal circuit is open.
Refer to DTC P0130 HO2S CIRCUIT (BANK 1/ SENSOR 1) .
The control unit of the linear oxygen sensor built inside the ECM monitors short circuit errors on all front Heated Oxygen Sensor (HO2S) control lines and the ECM sets P0131 with short circuit to ground.
Refer to DTC P0130 HO2S CIRCUIT (BANK 1/ SENSOR 1) .
The control unit of the linear oxygen sensor built inside the ECM monitors short circuit errors on all front Heated Oxygen Sensor (HO2S) control lines and the ECM sets P0132 with short circuit to battery.
Scheme 35
Refer to DTC P0130 HO2S CIRCUIT (BANK 1/ SENSOR 1) .
The ECM monitors front oxygen sensor amplitude level and compares it to predetermined minimum amplitude value which could increase emission or disturb lambda control by the effect of aging on the oxygen sensor. The ECM sets DTC P0133 when the amplitude of oxygen sensor is equal to or less than minimum amplitude threshold.
Refer to DTC P0130 HO2S CIRCUIT (BANK 1/ SENSOR 1) .
Due to possible oxygen sensor defects (e.g. reference air poisoning) or faults in the injection system (e.g. leaking fuel injector), the rear oxygen sensor may not provide the expected lean or rich signal level during fuel cut-off or full load condition. Hence, the oxygen sensor signal is checked for plausibility during this engine operating states.
DTC DETECTING CONDITION
| ITEM | DETECING CONDITION | POSSIBLE CAUSE | |
|---|---|---|---|
| Case1) | DTC Strategy | Signal plausibility during fuel cut off | Related fuse blown or missing Contact resistance in connectors HO2S contamination |
| Enable Conditions | Sensor preheating and full heating phases finished Fuel Cut Off active Integrated Mass Air Flow > 16g Battery voltage > 10V | ||
| Threshold Value | Voltage with fuel cut off > 0.1V | ||
| Diagnostic Time | 5 Sec. | ||
| Case2) | DTC Strategy | Signal stroke plausibility | |
| Enable Conditions | Sensor preheating and full heating phases finished Signal stroke valid (5 P-jump after Lambda regulation activation) Lambda controller is not on the limit Lean / rich cycle time < 2.5 sec. Battery voltage > 10V | ||
| Threshold Value | Sensor voltage < 0.25V | ||
| Diagnostic Time | 2 min. | ||
| MIL On Condition | 2 Driving Cycles | ||
DTC P0134 DETECTING CONDITION AND POSSIBLE CAUSE
The rear heated oxygen sensor is mounted on the rear side of the Catalytic Converter (warm-up catalytic converter) or in the rear exhaust pipe, which detects the catalyst efficiency. The rear heated oxygen sensor (HO2S) produces a voltage between 0V and 1V. This rear heated oxygen sensor is used to estimate the oxygen storage capability. If a catalyst has good conversion properties, the oxygen fluctuations are smoothed by the oxygen storage capacity of the catalyst. If the conversion provided by the catalyst is low due to aging, poisoning or misfiring, then the oxygen fluctuations are similar to signals from the front oxygen sensor.
ECM sets DTC P0136 if the ECM detects that the rear HO2S signal circuit is open.
Refer to DTC P0136 HO2S CIRCUIT (BANK 1/ SENSOR 2) .
ECM sets DTC P0137 if the ECM detects that the rear HO2S signal circuit is open.
Refer to DTC P0136 HO2S CIRCUIT (BANK 1/ SENSOR 2) .
ECM sets DTC P0138 if the ECM detects signal voltage higher than the possible range of a properly operating rear heated oxygen sensor (HO2S).
Refer to DTC P0136 HO2S CIRCUIT (BANK 1/ SENSOR 2) .
The ECM monitors rich-lean switching time of rear heated oxygen sensor (HO2S) after fuel cut-off to validate dynamic behavior of rear heated oxygen sensor (HO2S). After detection of fuel cut-off engine operating state, the ECM measures rich-lean switching time of the rear heated oxygen sensor (HO2S) signal and compares it to the predetermined limit value. DTC P0139 is set when the switching time is bigger than the limit value.
Refer to DTC P0136 HO2S CIRCUIT (BANK 1/ SENSOR 2) .
Due to possible oxygen sensor defects (e.g. reference air poisoning) or faults in the injection system (e.g. leaking fuel injector), the rear oxygen sensor may not provide the expected lean or rich signal level during fuel cut-off or full load condition. Hence, the oxygen sensor signal is checked for plausibility during this engine operating states. There are 2 cases which DTC P0140 sets.
- Signal monitoring during fuel cut-off: The ECM monitors rear O2 sensor signal level during fuel cut-off which normally shows near 0V and sets DTC P0140 when signal level is too high.
- Signal monitoring after fuel cut-off: The ECM monitors rear O2 sensor signal level for a certain time after leaving fuel cut-off and sets DTC P0140 when signal variation during checked period is too small.
In order to provide the best possible combination of drivability, fuel economy and emission control, the ECM uses a closed loop air/fuel metering system. The ECM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The ECM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The ECM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the amount reaches excessive levels because of a lean or rich condition.
If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The ECM sets DTC P0170 if no proportional fuel adaptation occurs for a defined time after the lambda controller has reached its minimum or maximum threshold.
Refer to DTC P0170 FUEL TRIM (BANK 1) .
Breaking lambda adaptation and lambda controller limits for a an extended period, which initially may have been caused by failures in the fuel or intake system, will involve emission rise, and therefore shall be diagnosed by fuel system monitoring. If same error code is set in the next driving cycle, the ECM illuminates the MIL. The lambda controller deviations, including adaptive terms, are used for fuel system monitoring. The time counter is increased if lambda controller deviations exceed a specific threshold and the ECM will then set DTC P0171 or P0172 respectively depending on the direction of the deviation. P0171 is set with positive deviation and P0172 is set with negative deviation.
Refer to DTC P0170 FUEL TRIM (BANK 1) .
Breaking lambda adaptation and lambda controller limits for a an extended period, which initially may have been caused by failures in the fuel or intake system, will involve emission rise, and therefore shall be diagnosed by fuel system monitoring. If same error code is set in the next driving cycle, the ECM illuminates the MIL. The lambda controller deviations, including adaptive terms, are used for fuel system monitoring. The time counter is increased if lambda controller deviations exceed a specific threshold and the ECM will then set DTC P0171 or P0172 respectively depending on the direction of the deviation. P0171 is set with positive deviation and P0172 is set with negative deviation.
The fluid of the CVVT is the engine oil and its density changes according to the engine oil temperature. At this time the Oil Temperature Sensor (OTS) helps compensation against the temperature differences. The Oil Temperature Sensor measures the engine oil temperature before the engine oil comes into the Oil-flow Control Valve (OCV). According to the measured temperature, the Engine Control Module (ECM) compensates the oil-flow control valve operation time.
The purpose of this diagnosis is to detect a stuck oil temperature signal or unplausibly low, high signal. For the stuck signal detection, the ECM sets DTC P0196 if the variation of the measured oil temperature is lower than the threshold. For the unplausibly high, low signal detection, the ECM compares measured engine oil temperature with calculated oil temperature or coolant temperature and sets DTC P0196 when one of following conditions is met.
- Measured oil temperature is unplausibly low when calculated oil temperature is high.
- Measured oil temperature is unplausibly high when coolant temperature is low without any relevant failure.
Refer to DTC P0196 ENGINE OIL TEMP. SENSOR RANGE / PERFORMANCE .
ECM sets DTC P0197 if the ECM detects signal voltage lower than the possible range of a properly operating OTS.
Refer to DTC P0196 ENGINE OIL TEMP. SENSOR RANGE / PERFORMANCE .
ECM sets DTC P0198 if the ECM detects signal voltage higher than the possible range of a properly operating OTS.
The ECM provides ground to one side of the coil in the fuel pump relay to control the fuel pump relay. The other side of the fuel pump relay coil is connected to fuel pump relay, which activates when the ignition switch is ON. The ECM monitors the control circuit between the fuel pump relay and the ECM. When the ignition switch is turned ON, the ECM energizes the fuel pump relay, which sends power to the fuel pump.
ECM sets DTC P0230 if the ECM detects the fuel pump relay control circuit is open, short to ground or battery.
Based on information from various sensors, the ECM measures the fuel injection amount. The fuel injector is a solenoid-operated valve and the fuel injection amount is controlled by length of time the fuel injector is held open. The ECM controls each injector by grounding the control circuit. When the ECM energizes the injector by grounding the control circuit, the circuit voltage should be low (theoretically 0V) and the fuel is injected. When the ECM de-energizes the injector by opening the control circuit, the fuel injector is closed and circuit voltage should momentarily peak.
ECM sets DTC P0261/P0264/P0267/P0270 if the ECM detects that injector (Cylinder #1/2/3/4) control circuit is shorted to ground.
Refer to DTC P0261 CYLINDER 1-INJECTOR CIRCUIT LOW; DTC P0264 CYLINDER 2-INJECTOR CIRCUIT LOW; DTC P0267 CYLINDER 3-INJECTOR CIRCUIT LOW; DTC P0270 CYLINDER 4-INJECTOR CIRCUIT LOW .
ECM sets DTC P0262/P0265/P0268/P0271 if the ECM detects that injector (Cylinder #1/2/3/4) control circuit is open or shorted to battery voltage.
The Misfire monitor diagnostic is based on crankshaft rotation velocity variation. The ECM determines crankshaft rotational velocity using the crankshaft position sensor and camshaft position sensor. When a cylinder misfires the crankshaft slows down momentarily. By monitoring the crankshaft and camshaft position sensor signals, the ECM can calculate when a misfire occurs. For a non-catalyst damaging misfire, the diagnostic will be required to report a misfire present within 1000-3200 engine revolutions. For catalyst damaging misfire, the diagnostic will respond to monitor 200 engine revolutions. Rough roads may cause false misfire detection. The rough road(acceleration)sensor consists of a piezoelectric vibration pick up which detects vertical acceleration of the vehicle. The sensor signal is used by the ECM to determine the degree of vertical movement of the car, for example, on a bumpy road. Since this may also cause uneven engine running, the ECM uses the signal to distinguish the phenomenon from actual misfiring.
The ECM must monitor the engine for misfiring possibly caused by ignition coil defects or injector fails. If misfiring is detected, the ECM will identify the cylinder(s) that has(have) misfired and then calculate misfiring rate for a given duration. The DTC for Misfire (P0301 to 0304) is set as soon as the misfiring rate exceeds the limit which may result in damage to the catalyst or increase emissions. The ECM stores the individual DTC for a cylinder which has more than a 10% total misfire rate. With a more than two cylinder misfire detection, the ECM sets P0300.
A Misfire induces a decrease in the engine speed and causes a variation in the segment period. Therefore, misfiring detection is based on the observation of this variation of the segment period.
Because of the tolerance in mechanical machining and assembling process of the target wheel, the duration of each segment are not always same but differ from segment to segment on the same engine. And this irregular segment duration can disturb misfiring detection which is based on the difference of engine rotational speed between the firing and the misfiring cylinder. The ECM compares segment duration of 4 cylinders during fuel cut-off and deceleration period. With this comparison ECM perform segment adaptation to adapt the difference of each segment duration.
The ECM sets DTC P0315 if any of segment adaptation value is on the limit.
The knock sensor is attached to the cylinder block and senses engine knocking. The sensor contains a piezoelectric element that converts vibration (or noise) into voltage signal and sends this signal to ECM. With input signals from camshaft position and crankshaft position sensor, ECM can identify which cylinder is knocking. ECM filters vibrations and determines if the vibrations are knocking signal. The Engine Control Module (ECM) uses this signal to suppress knocking by retarding ignition timing. The ECM will set a code (Malfunction Indicator Lamp will Not turn on) if during two driving cycles the Knock sensor's output voltage falls below minimum threshold. This code indicates an unexpected vibration is being read by the Knock sensor or ECM under normal engine operation.
The ECM monitors the range of the analog input signal from knock sensor to check sensor failure that is short circuit or open circuit. If the difference between knock signal and noise level is smaller than the threshold during defined time period, the DTC P0325 is set. In case the noise level is higher than the upper threshold or lower than the lower threshold, the DTC P0325 is set too.
The Crankshaft Position Sensor (CKPS) is a hall effect type sensor that generates voltage using a sensor and a target wheel mounted on the crankshaft; there are 58 slots in the target wheel where one is longer than the others. When the slot in the wheel aligns with the sensor, the sensor voltage outputs low. When the metal (tooth) in the wheel aligns with the sensor, the sensor voltage outputs high. During one crankshaft rotation there are 58 rectangular signals and one longer signal. The ECM calculates engine RPM by using the sensor' s signal and controls the injection duration and the ignition timing. Using the signal differences caused by the longer slot, the ECM identifies which cylinder is at top dead center.
The ECM sets DTC P0335 when the number of crankshaft teeth during one revolution is incorrect or crankshaft signal is missing while camshaft signal is detected.
The Camshaft Position Sensor (CMPS) is a sensor that detects the compression TDC of the NO. 1 cylinder.
The CMPS consists of a hall type sensor and a target on the end of the intake camshaft.
When the target triggers the sensor, the sensor voltage is 5V. If not, the sensor voltage is OV. These CMPS signal is sent to the ECM and the ECM uses the CMPS signal for synchronizing the firing of sequential fuel injectors.
The ECM monitors the camshaft sensor signal transition position which must change only once per crankshaft revolution. If no camshaft signal is detected while crankshaft signal is detected, the ECM sets DTC P0340.
The ECM uses dual oxygen sensors to monitor the efficiency of the manifold catalytic converter (warm-up catalytic converter). By monitoring the oxygen storage capacity of a catalyst, its efficiency can be indirectly calculated. The upstream (front) HO2S is used to detect the amount of oxygen in the exhaust gas before it enters the catalytic converter. A low voltage indicates high oxygen contents (lean air mixture). A high voltage indicates low oxygen contents (rich air mixture). When the catalyst efficiency drops, no chemical reaction takes place. This means the concentration of oxygen will be the same at the rear as it is at the front. The output voltage of the rear HO2S copies the voltage of the front HO2S.To monitor the system, the lean-to-rich switches of the front HO2S to the rear HO2S is counted. The ratio of rear switches to front switches is used to determine whether the catalyst is operating properly. An effective catalyst will have fewer rear switches than front switches, that is, a ratio closer to zero.
The ECM calculates oscillation size of rear HO2S signal which represents catalyst conversion properties. This oscillation size will determine if catalyst conversion is low due to aging or poisoning from leaded fuel or misfiring. The ECM sets P0420 if the average of calculated oscillation size of rear HO2S signal during predetermined duration is higher than the predetermined threshold.
Scheme 36
The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustion. This valve is actuated by the purge control signal from the ECM and controls fuel vapor from the canister to the intake manifold.
During "test of vapour generation" a new value from the tank pressure sensor is measured and compared with the start pressure at beginning of "test of vapour generation".
The ECM sets DTC P0441 if the pressure signal decrease occurs and the difference is below the predetermined threshold. If same error code is set in the next driving cycle, the ECM illuminates the MIL.
Due to the increasing ambient temperature of the fuel and the return of unused hot fuel from the engine, fuel vapors are generated in the tank. In order to control the release of these vapors to the atmosphere, the evaporative emissions control system is used. The evaporative emission control system reduces hydrocarbon (HC) emissions by trapping fuel tank vapors until they can be burned in the combustion process. Evaporating fuel is stored in a charcoal canister until it can be flushed into the intake manifold. The evaporative emission control system is made up of a fuel tank that can be completely sealed from outside air, a Fuel Tank Pressure Sensor (FTPS), a Canister Close Valve (CCV) that seals the canister from the outside air, a canister filled with activated charcoal granules, a Purge Control Solenoid Valve (PCSV). The evaporative emission system can be checked for leaks by sealing the system off from the outside air, creating a vacuum, and monitoring if the system can hold that vacuum sufficiently for a set amount of time. If it cannot, a leak exists somewhere in the system.
The ECM closes the Canister Close Valve (CCV) at the charcoal canister to seal off the evaporative emission system and then opens purge control valve (PCSV) to generate a vacuum in the fuel tank. After vacuum generation, the ECM measures pressure differential curve in the fuel tank and sets DTC P0442 or P0456 if the vacuum generated within a monitoring period increases above a defined threshold.
If same error code is set in the next driving cycle, the ECM illuminates the MIL.
The evaporative emission control system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustion. This valve is actuated by the purge control signal from the ECM and controls fuel vapor flow from the canister to the intake manifold.
ECM sets DTC P0444 if the ECM detects that the PCSV control circuit is open.
Refer to DTC P0444 EVAP. EMISSION SYSTEM-PURGE CTRL. VALVE CIRCUIT OPEN .
ECM sets DTC P0445 if the ECM detects that the PCSV control circuit is shorted to ground or shorted to battery voltage.
The evaporative emissions system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The Canister Closing Valve (CCV) closes off the air inlet into the canister for leak detection of the evaporative emission system. The CCV also prevents fuel vapors from escaping from the canister. When the engine purges the HC vapors from the canister, the clean air comes into the canister through the canister air-filter and the CCV.
ECM sets DTC P0447 if the ECM detects that the CCV control line is open.
Refer to DTC P0447 EVAP. EMISSION SYSTEM-VENT CONTROL CIRCUIT OPEN .
ECM sets DTC P0448 if the ECM detects that the CCV control line is short to ground or short to battery line.
Refer to DTC P0447 EVAP. EMISSION SYSTEM-VENT CONTROL CIRCUIT OPEN .
The ECM measures pressure in the fuel tank by means of tank pressure sensor during all engine operating states except engine stop and start. The DTC P0449 is set if pressure is lower than predetermined threshold.
If same error code is set in the next driving cycle, the ECM illuminates the MIL.
The evaporative emission control system prevents hydrocarbon vapors from escaping from the fuel tank into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The Fuel Tank Pressure Sensor (FTPS) is an integral part of the evaporative monitoring system. The ECM monitors the FTPS signal to detect vacuum decay and excess vacuum. The FTPS measures the difference between the air pressure inside the fuel tank and outside air pressure to check the purge control solenoid valve operation and for leak detection in the evaporative emission control system by monitoring pressure and vacuum levels in the fuel tank during the purge control solenoid valve operating cycles.
The ECM monitors pressure in the fuel tank by means of Fuel Tank Pressure Sensor (FTPS) during purge control valve opening or closing phase. This monitoring will determine if pressure sensor signal is stuck. The ECM sets DTC P0451 if pressure variation is smaller than the predetermined threshold.
If same error code is set in the next driving cycle, the ECM illuminates the MIL.
Refer to DTC P0451 EVAP. EMISSION SYSTEM-PRESSURE SENSOR RANGE/PERFORMANCE .
ECM sets DTC P0452 if the ECM detects signal voltage lower than the possible range of a properly operating FTPS.
Refer to DTC P0451 EVAP. EMISSION SYSTEM-PRESSURE SENSOR RANGE/PERFORMANCE .
ECM sets DTC P0453 if the ECM detects signal voltage higher than the possible range of a properly operating FTPS.
Refer to DTC P0451 EVAP. EMISSION SYSTEM-PRESSURE SENSOR RANGE/PERFORMANCE .
The ECM monitors pressure stability in the fuel tank by means of Fuel Tank Pressure Sensor (FTPS) for predetermined duration just before start the leakage monitoring to detect noise signal of pressure sensor. The ECM sets DTC P0454 if the pressure fluctuation is bigger than predetermined threshold.
If same error code is set in the next driving cycle, the ECM illuminates the MIL.
Due to the increasing ambient temperature of the fuel and the return of unused hot fuel from the engine, fuel vapors are generated in the tank. In order to control the release of these vapors to the atmosphere, the evaporative emissions control system is used. The evaporative emission control system reduces hydrocarbon (HC) emissions by trapping fuel tank vapors until they can be burned in the combustion process. Evaporating fuel is stored in a charcoal canister until it can be flushed into the intake manifold. The evaporative emission control system is made up of a fuel tank that can be completely sealed from outside air, a Fuel Tank Pressure Sensor (FTPS), a Canister Close Valve (CCV) that seals the canister from the outside air, a canister filled with activated charcoal granules, a Purge Control Solenoid Valve (PCSV). The evaporative emission system can be checked for leaks by sealing the system off from the outside air, creating a vacuum, and monitoring if the system can hold that vacuum sufficiently for a set amount of time. If it cannot, a leak exists somewhere in the system.
The ECM closes the Canister Close Valve (CCV) at the charcoal canister to seal off the evaporative emission system and then opens purge control valve (PCSV) to generate a vacuum in the fuel tank. This vacuum generation phase will determine if there is a large leak like tank cap open or canister shut off valve (CCV) stuck open. The ECM sets DTC P0455 if the pressure in the fuel tank does not drop as low as predetermined threshold during predetermined maximum vacuum generation period.
If the same error code is set in the next driving cycle, the ECM illuminates the MIL.
The Wheel Speed Sensor (WSS) generates a waveform with a frequency proportional to the speed of the vehicle. The signal generated by the WSS informs the ECM not only if the vehicle speed is low or high but also if the vehicle is or is not moving. The ECM uses this signal to control the fuel injection, ignition timing, transaxle shift scheduling and torque converter clutch scheduling. The WSS signal is also used to detect rough road conditions.
The ECM evaluates engine speed and mass air flow if there is no vehicle speed signal. This evaluation of both values will detect open circuit or short circuit errors on the wheel speed sensor. The ECM sets DTC P0501 if there is no vehicle speed signal from wheel speed sensor while both engine speed and mass air flow are higher than predetermined threshold during the predetermined time.
When the TP sensor's signal indicates closed throttle position and the engine is idling, the ECM adjusts the idle speed control actuator so that the engine runs at the correct idling speed, regardless of coolant temperature, load and etc. When the additional load applied in the engine, the air flow through the idle speed control actuator is increased momentarily to raise the idling speed.
The ECM monitors engine speed deviation from the target idle engine speed when the vehicle is stopped and the idle speed valve opening is stable. The ECM sets DTC P0506 if the difference to the target idle engine speed is lower than the predetermined threshold.
Refer to DTC P0506 IDLE AIR CONTROL SYSTEM-RPM LOWER THAN EXPECTED .
The ECM monitors engine speed deviation from the target idle engine speed when the vehicle is stopped and the idle speed valve opening is stable. The ECM sets DTC P0507 if the difference to the target idle engine speed is higher than the predetermined threshold.
The ECM provides ground to one side of the coil of the main relay and the other side is connected to the battery. The ECM monitors battery voltage and the voltage after the main relay.
The ECM measures the voltage from ignition key and from main relay respectively and compares two voltages. This comparison will watch if the Main Relay has switched and remains on after ignition Key-On and if it has switched off after the ignition Key-Off. The ECM sets DTC P0560 if the voltage after Main Relay is lower than a predetermined threshold after ignition key-on or higher than a predetermined threshold after ignition key-off.
Refer to DTC P0560 SYSTEM VOLTAGE .
The sets DTC P0562 if the ECM detects system voltage lower than the possible range of battery voltage.
The sets DTC P0563 if the ECM detects system voltage higher than the possible range of battery voltage.
A communication line exists between the Engine Control Module(ECM) and the Transaxle Control Module(TCM). The communication is through a Control Area Network(CAN). Without CAN communication, an independent pin and wiring is needed to receive a sensor information from a ECM. The more information to be communicated, the more wirings is required. In case of CAN communication type, all the information need to be communicated among control modules such as ECM and ABS control module use CAN lines.
The ECM determines CAN communication error and sets DTC P0600 if communication with other engine control devices (e.g. ABS) via CAN is impossible or ECM detects that communication time via CAN exceeds threshold value.
A malfunction is detected by using a checksum technique for verifying data. The digital data is composed of zeros and ones. A checksum is the total of all ones in a string of data. By comparing the checksum value with a stored value, a malfunction can be detected.
The ECM monitors RAM areas and communication connections between micro controller and output drivers and sets DTC P0605 if failure is detected.
The ECM monitors ROM areas and sets DTC P0630 if there is no Vehicle Identification Number(VIN) information.
The Malfunction Indicator Lamp (MIL), which is located in the instrument cluster, comes on to notify the driver that there may be a problem with the vehicle and that service is needed. Immediately after the ignition switch turns on, the malfunction indicator lamp is lit to indicate that the MIL operates normally and goes off after starting.
ECM sets DTC P0650 if the ECM detects that the MIL control line is open or short circuit to ground or battery line.
The TCM can request activation of the MIL lamp via a communication line to the ECM. This is only a request from TCM to ECM to turn the MIL on. The fault code is stored in the TCM. Select Transaxle system on the Scantool and monitor DTC related automatic transaxle system.
DO ALL REPAIRS associated malfunction with A/T.
The Idle Speed Control Actuator (ISCA) is installed on the intake manifold and controls the intake airflow that is bypassed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the ISCA valve is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA valve consists of an opening coil, a closing coil, and a permanent magnet. Based on information from various sensors, the ECM controls both coils by grounding their control circuits. According to the control signals from the ECM, the valve rotor rotates to control the by pass airflow into the engine.
[P1505] ECM sets DTC P1505 if the ECM detects that the ISCA(OPEN) control circuit is open or short to ground.
[P1507] ECM sets DTC P1507 if the ECM detects that the ISCA(CLOSE) control circuit is open or short to ground.
Refer to DTC P1505 IDLE CHARGE ACTUATOR SIGNAL LOW OF COIL #1; DTC P1507 IDLE CHARGE ACTUATOR SIGNAL LOW OF COIL #2 .
[P1506] ECM sets DTC P1506 if the ECM detects that the ISCA(OPEN) control circuit is short to battery.
[P1508] ECM sets DTC P1508 if the ECM detects that the ISCA(CLOSE) control circuit is short to battery.