2.4L - Dtcs B104D to P0501: Overview Dodge Dart PF

THEORY OF OPERATION

The Powertrain Control Module factors the Blend Door position and Blower Motor speed information into the coolant temperature modeling. This information is received as a raw voltage signal from the HVAC Module over the Can Bus.

The Powertrain Control Module factors the Blend Door position and Blower Motor speed information into the coolant temperature modeling. This information is received as a raw voltage signal from the HVAC Module over the Can Bus.

The Powertrain Control Module factors the Blend Door position and Blower Motor speed information into the coolant temperature modeling. This information is received as a raw voltage signal from the HVAC Module over the Can Bus.

The Powertrain Control Module factors the Blend Door position and Blower Motor speed information into the coolant temperature modeling. This information is received as a raw voltage signal from the HVAC Module over the Can Bus.

The Camshaft Position (CMP) Sensor circuits consist of an Powertrain Control Module (PCM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel attached to the camshaft. As each tooth rotates past the CMP Sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency output pulses per Camshaft revolution that represent an image of the camshaft tone wheel. The frequency of the CMP Sensor output depends on the velocity of the camshaft. The PCM decodes the tooth pattern to identify camshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CMP Sensor output information to determine the camshaft relative position to the Crankshaft, to control the CMP Actuator operation if equipped.

For the Wideband 02 Sensor to deliver accurate readings the sensing elements must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. The PCM monitors the O2 Sensor's heater for proper operation. If a malfunction occurs the circuit is turned off and a DTC will set.

For the Wideband 02 Sensor to deliver accurate readings the sensing elements must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. The PCM monitors the O2 Sensor's heater for proper operation. If a malfunction occurs the circuit is turned off and a DTC will set.

For the 02 Sensor to deliver accurate readings the sensing element must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. During operation the heater circuit is momentarily disabled to allow a resistance measurement to be taken to infer heater temperature. The current delivery to the heater is duty cycled to maintain a specific target temperature. The error from the target temperature is continuously monitored to assess heater performance. If a malfunction occurs the circuit is turned off and a DTC will set.

For the 02 Sensor to deliver accurate readings the sensing element must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. During operation the heater circuit is momentarily disabled to allow a resistance measurement to be taken to infer heater temperature. The current delivery to the heater is duty cycled to maintain a specific target temperature. The error from the target temperature is continuously monitored to assess heater performance. If a malfunction occurs the circuit is turned off and a DTC will set.

Ambient Air Temperature (AAT) Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. The AAT Sensor reading is a BUS message from the Body Control Module (BCM) to the Powertrain Control Module (PCM). Following a start to run delay time, the outputs of the ambient, engine coolant and intake air temperature sensors are compared. The AAT Sensor is a variable resistor that measures the ambient air temperature. The BCM supplies a 5-Volt reference and a ground to the sensors low reference signal circuit. When the ambient air temperature is low, the sensor resistance is high. When the ambient air temperature is high, the sensor resistance is low.

The Ambient Air Temperature (AAT) Sensor reading is a bussed message from the Body Control Module (BCM) to the Powertrain Control Module (PCM). The AAT Sensor is a variable resistor that functions as a typical two wire sensor. The BCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit. When the ambient air temperature is low, the sensor resistance is high. When the ambient air temperature is high, the sensor resistance is low.

If during normal operation the Ambient Air Temperature Sensor voltage goes above a calibrated maximum voltage threshold or below a calibrated minimum voltage threshold, the PCM will set a circuit fault. The PCM also does a plausibility check of the input signals of the Ambient Air, Engine Coolant and Intake Air Temperature Sensors under cold start conditions.

The Ambient Air Temperature (AAT) Sensor reading is a bussed message from the Body Control Module (BCM) to the Powertrain Control Module (PCM). The AAT Sensor is a variable resistor that functions as a typical two wire sensor. The BCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit. When the ambient air temperature is low, the sensor resistance is high. When the ambient air temperature is high, the sensor resistance is low.

If during normal operation the Ambient Air Temperature Sensor voltage goes above a calibrated maximum voltage threshold or below a calibrated minimum voltage threshold, the PCM will set a circuit fault. The PCM also does a plausibility check of the input signals of the Ambient Air, Engine Coolant and Intake Air Temperature Sensors under cold start conditions.

The Manifold Absolute Pressure (MAP) Sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP Sensor reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the intake manifold. The PCM uses this information to calculate fuel delivery. The MAP Sensor has a 5-Volt reference circuit, a low reference circuit and a signal circuit. The PCM supplies 5 volts to the MAP Sensor on a 5-Volt reference circuit and provides a ground on a low reference circuit. The MAP Sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes.

The Manifold Absolute Pressure (MAP) Sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP Sensor reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the intake manifold. The PCM uses this information to calculate fuel delivery. The MAP Sensor has a 5-Volt reference circuit, a low reference circuit and a signal circuit. The PCM supplies 5 volts to the MAP Sensor on a 5-Volt reference circuit and provides a ground on a low reference circuit. The MAP Sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes.

Intake Air Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant and intake air temperature sensors will be compared. If the engine coolant and ambient air temperature sensors agree and the intake air temperature does not agree, the intake air temperature sensor is declared as irrational. If declared irrational a second comparison will be done after a short drive cycle. The IAT Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit.

The Inlet Air Temperature (IAT) Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit. When the inlet air temperature is low, the sensor resistance is high. When the inlet air temperature is high, the sensor resistance is low.

The Inlet Air Temperature (IAT) Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit. When the inlet air temperature is low, the sensor resistance is high. When the inlet air temperature is high, the sensor resistance is low.

Coolant Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant and intake air temperature sensors will be compared. If the inlet air and ambient air temperature sensors agree and the coolant temperature does not agree, the coolant temperature sensor is declared as irrational. If declared irrational a second comparison will be done after a short drive cycle. The Coolant Temperature Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference and a ground to the sensors low reference signal circuit.

The Coolant Temperature Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference on the signal circuit, and a ground to the sensors low reference signal circuit.

The Coolant Temperature Sensor is a variable resistor that functions as a normal two wire 5 volt sensor. The PCM supplies a 5 volt reference on the signal circuit, and a ground to the sensors low reference signal circuit.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The wide-band O2 Sensor operates differently than traditional O2 Sensors. The wide-band O2 Sensor tip consists of two cells that provide different functions, a measurement chamber and a detection chamber with pumping capabilities. The oxygen pumping function is the ability to pump oxygen into or out of the measurement chamber depending on the level of oxygen in the measurement chamber. This function provides the wide-band sensing capabilities and is critical for proper oxygen measurement. The O2 Sensor Reference circuit provides a common bias supply to both the O2 Sensor Signal and the O2 Sensor Pump Cell Current circuits.

During normal operation, the O2 Sensor Reference voltage and O2 Sensor Signal voltage will be a fixed voltage value. The O2 Sensor Current Pump voltage will switch from between 0.45 volts above and below the fixed O2 Sensor Return voltage, allowing current to flow in either direction through the pump. This correlates with the pumping of oxygen into and out of the measurement chamber. On a properly operating vehicle, this happens very quickly and the voltage reading should maintain a steady 0.45 volts when taking a voltage measurement between the O2 Sensor Signal circuit and the O2 Sensor Reference circuit of the O2 Sensor with the engine running and the O2 Sensor operating in closed loop.

When the exhaust stream has a lean air/fuel ratio (high oxygen content) the pumping element voltage will move toward +0.45 volts pumping oxygen out of the measurement chamber. When the exhaust stream has a rich air/fuel ratio (relatively low oxygen content) the pumping element voltage will move toward -0.45 volts pumping oxygen into the measurement chamber.

For the Wideband 02 Sensor to deliver accurate readings the sensing elements must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. The PCM monitors the O2 Sensor's heater for proper operation. If a malfunction occurs the circuit is turned off and a DTC will set.

The Oxygen Sensors (O2 Sensor) are used for fuel control and catalyst monitoring. Each O2 Sensor measures the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 Sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 Sensor heats the sensor to bring it to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 Sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 Sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 Sensor voltage to determine the air-to-fuel ratio. An O2 Sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 Sensor voltage that decreases toward 0 mV indicates a lean fuel mixture. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoichiometric fuel/air ratio for best catalytic converter efficiency. Short term fuel correction is based on upstream O2 Sensor output and is designed for quick engine response. The long term fuel correction compensated for variations in the engine specifications, sensor tolerances and component aging and is designed to correct rich and lean conditions over a longer period of time.

For an aged O2 Sensor, the response rate to the air/fuel change is slower than when it was new. The O2 Sensor tends to move less with the same air/fuel changes in a given time frame. Therefore by observing the activity of voltage readings from the upstream O2 Sensor, the quality of the O2 Sensor can be detected.

The Oxygen Sensors (O2 Sensor) are used for fuel control and catalyst monitoring. Each O2 Sensor measures the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 Sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 Sensor heats the sensor to bring it to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 Sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 Sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 Sensor voltage to determine the air-to-fuel ratio. An O2 Sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 Sensor voltage that decreases toward 0 mV indicates a lean fuel mixture. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoichiometric fuel/air ratio for best catalytic converter efficiency. Short term fuel correction is based on upstream O2 Sensor output and is designed for quick engine response. The long term fuel correction compensated for variations in the engine specifications, sensor tolerances and component aging and is designed to correct rich and lean conditions over a longer period of time.

For an aged O2 Sensor, the response rate to the air/fuel change is slower than when it was new. The O2 Sensor tends to move less with the same air/fuel changes in a given time frame. Therefore by observing the activity of voltage readings from the upstream O2 Sensor, the quality of the O2 Sensor can be detected.

The Oxygen Sensors (O2 Sensor) are used for fuel control and catalyst monitoring. Each O2 Sensor measures the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 Sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 Sensor heats the sensor to bring it to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 Sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 Sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 Sensor voltage to determine the air-to-fuel ratio. An O2 Sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 Sensor voltage that decreases toward 0 mV indicates a lean fuel mixture. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoichiometric fuel/air ratio for best catalytic converter efficiency. Short term fuel correction is based on upstream O2 Sensor output and is designed for quick engine response. The long term fuel correction compensated for variations in the engine specifications, sensor tolerances and component aging and is designed to correct rich and lean conditions over a longer period of time.

For an aged O2 Sensor, the response rate to the air/fuel change is slower than when it was new. The O2 Sensor tends to move less with the same air/fuel changes in a given time frame. Therefore by observing the activity of voltage readings from the upstream O2 Sensor, the quality of the O2 Sensor can be detected.

The Oxygen Sensors (O2 Sensor) are used for fuel control and catalyst monitoring. Each O2 Sensor measures the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 Sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 Sensor heats the sensor to bring it to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 Sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 Sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 Sensor voltage to determine the air-to-fuel ratio. An O2 Sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 Sensor voltage that decreases toward 0 mV indicates a lean fuel mixture. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoichiometric fuel/air ratio for best catalytic converter efficiency. Short term fuel correction is based on upstream O2 Sensor output and is designed for quick engine response. The long term fuel correction compensated for variations in the engine specifications, sensor tolerances and component aging and is designed to correct rich and lean conditions over a longer period of time.

For an aged O2 Sensor, the response rate to the air/fuel change is slower than when it was new. The O2 Sensor tends to move less with the same air/fuel changes in a given time frame. Therefore by observing the activity of voltage readings from the upstream O2 Sensor, the quality of the O2 Sensor can be detected.

For the 02 Sensor to deliver accurate readings the sensing element must be heated. A Positive Temperature Coefficient (PTC) element inside the O2 Sensor heats up as current passes through it. This allows the system to enter Closed Loop quickly. The Powertrain Control Module (PCM) turns on this circuit based on Engine Coolant Temperature (ECT) and engine loads. During operation the heater circuit is momentarily disabled to allow a resistance measurement to be taken to infer heater temperature. The current delivery to the heater is duty cycled to maintain a specific target temperature. The error from the target temperature is continuously monitored to assess heater performance. If a malfunction occurs the circuit is turned off and a DTC will set.

The wide-band O2 Sensor operates differently than traditional O2 Sensors. The wide-band O2 Sensor tip consists of two cells that provide different functions, a measurement chamber and a detection chamber with pumping capabilities. The oxygen pumping function is the ability to pump oxygen into or out of the measurement chamber depending on the level of oxygen in the measurement chamber. This function provides the wide-band sensing capabilities and is critical for proper oxygen measurement. The O2 Sensor Reference circuit provides a common bias supply to both the O2 Sensor Signal and the O2 Sensor Pump Cell Current circuits.

During normal operation, the O2 Sensor Reference voltage and O2 Sensor Signal voltage will be a fixed voltage value. The O2 Sensor Current Pump voltage will switch from between 0.45 volts above and below the fixed O2 Sensor Return voltage, allowing current to flow in either direction through the pump. This correlates with the pumping of oxygen into and out of the measurement chamber. On a properly operating vehicle, this happens very quickly and the voltage reading should maintain a steady 0.45 volts when taking a voltage measurement between the O2 Sensor Signal circuit and the O2 Sensor Reference circuit of the O2 Sensor with the engine running and the O2 Sensor operating in closed loop.

When the exhaust stream has a lean air/fuel ratio (high oxygen content) the pumping element voltage will move toward +0.45 volts pumping oxygen out of the measurement chamber. When the exhaust stream has a rich air/fuel ratio (relatively low oxygen content) the pumping element voltage will move toward -0.45 volts pumping oxygen into the measurement chamber.

The wide-band O2 Sensor operates differently than traditional O2 Sensors. The wide-band O2 Sensor tip consists of two cells that provide different functions, a measurement chamber and a detection chamber with pumping capabilities. The oxygen pumping function is the ability to pump oxygen into or out of the measurement chamber depending on the level of oxygen in the measurement chamber. This function provides the wide-band sensing capabilities and is critical for proper oxygen measurement. The O2 Sensor Reference circuit provides a common bias supply to both the O2 Sensor Signal and the O2 Sensor Pump Cell Current circuits.

During normal operation, the O2 Sensor Reference voltage and O2 Sensor Signal voltage will be a fixed voltage value. The O2 Sensor Current Pump voltage will switch from between 0.45 volts above and below the fixed O2 Sensor Return voltage, allowing current to flow in either direction through the pump. This correlates with the pumping of oxygen into and out of the measurement chamber. On a properly operating vehicle, this happens very quickly and the voltage reading should maintain a steady 0.45 volts when taking a voltage measurement between the O2 Sensor Signal circuit and the O2 Sensor Reference circuit of the O2 Sensor with the engine running and the O2 Sensor operating in closed loop.

When the exhaust stream has a lean air/fuel ratio (high oxygen content) the pumping element voltage will move toward +0.45 volts pumping oxygen out of the measurement chamber. When the exhaust stream has a rich air/fuel ratio (relatively low oxygen content) the pumping element voltage will move toward -0.45 volts pumping oxygen into the measurement chamber.

The Engine Oil Temperature (EOT) Sensor is a variable resistor that measures the temperature of the engine oil. It operates as a typical two wire sensor. The Powertrain Control Module (PCM) supplies the sensor with a 5-Volt reference and a sensor ground circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.

The Engine Oil Temperature (EOT) Sensor is a variable resistor that measures the temperature of the engine oil. It operates as a typical two wire sensor. The Powertrain Control Module (PCM) supplies the sensor with a 5-Volt reference and a sensor ground circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.

The Engine Oil Temperature (EOT) Sensor is a variable resistor that measures the temperature of the engine oil. It operates as a typical two wire sensor. The Powertrain Control Module (PCM) supplies the sensor with a 5-Volt reference and a sensor ground circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.

The electronic Fuel Injector is supplied power via the Fused Automatic Shut Down (ASD) Relay Output circuit. The Powertrain Control Module (PCM) provides a pulse width modulated (PWM) signal to the injector's solenoid coil to inject pressurized fuel just upstream of each cylinder's intake valve. Each injector receives a unique pulse width based on that cylinder's fuel requirements. The PCM determines this fuel requirement by monitoring engine operating parameters via various sensors and then calculating the appropriate amount of fuel to be injected. The optimum amount of injected fuel depends on conditions such as engine and ambient temperatures, engine speed and workload, and exhaust gas composition.

The electronic Fuel Injector is supplied power via the Fused Automatic Shut Down (ASD) Relay Output circuit. The Powertrain Control Module (PCM) provides a pulse width modulated (PWM) signal to the injector's solenoid coil to inject pressurized fuel just upstream of each cylinder's intake valve. Each injector receives a unique pulse width based on that cylinder's fuel requirements. The PCM determines this fuel requirement by monitoring engine operating parameters via various sensors and then calculating the appropriate amount of fuel to be injected. The optimum amount of injected fuel depends on conditions such as engine and ambient temperatures, engine speed and workload, and exhaust gas composition.

The electronic Fuel Injector is supplied power via the Fused Automatic Shut Down (ASD) Relay Output circuit. The Powertrain Control Module (PCM) provides a pulse width modulated (PWM) signal to the injector's solenoid coil to inject pressurized fuel just upstream of each cylinder's intake valve. Each injector receives a unique pulse width based on that cylinder's fuel requirements. The PCM determines this fuel requirement by monitoring engine operating parameters via various sensors and then calculating the appropriate amount of fuel to be injected. The optimum amount of injected fuel depends on conditions such as engine and ambient temperatures, engine speed and workload, and exhaust gas composition.

The electronic Fuel Injector is supplied power via the Fused Automatic Shut Down (ASD) Relay Output circuit. The Powertrain Control Module (PCM) provides a pulse width modulated (PWM) signal to the injector's solenoid coil to inject pressurized fuel just upstream of each cylinder's intake valve. Each injector receives a unique pulse width based on that cylinder's fuel requirements. The PCM determines this fuel requirement by monitoring engine operating parameters via various sensors and then calculating the appropriate amount of fuel to be injected. The optimum amount of injected fuel depends on conditions such as engine and ambient temperatures, engine speed and workload, and exhaust gas composition.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. The TPS Sensors 1 and 2 are located within the throttle body assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides the processors with a signal voltage proportional to throttle blade movement. The processors share and monitor data to verify that the indicated TPS calculation is correct.

The Engine Oil Temperature (EOT) Sensor is a variable resistor that measures the temperature of the engine oil. It operates as a typical two wire sensor. The Powertrain Control Module (PCM) supplies the sensor with a 5-Volt reference and a sensor ground circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, lack of spark or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.

Knock is the spontaneous auto-ignition of the remaining fuel/air mixture in the engine combustion chamber that occurs after normal combustion has started. It can occur under extreme vehicle operating conditions such as high engine temperature, high MAP, low humidity and heavy loads to the engine. Knock is caused by excessive spark advance for the given engine operating conditions. Severe, continuous knock may be caused by carbon deposits, bad gasoline and/or low octane fuel. Avoiding light audible knock is important for customer satisfaction while preventing excessive knock is important to protect engine components. The output voltage from the knock circuit represents the strength of the engine knock and is read by the engine controller. The knock system output voltage is not zero due to engine background noise, even when knock is not present. When the engine is operated under high load conditions where knock is possible, the knock voltage is tested to decide if it exceeds the knock voltage threshold. Knock has occurred when the knock voltage is at or above this knock threshold. When knock is detected a calibrated short term knock spark retard to be subtracted from the spark advance is calculated. The amount of retarded spark advance is based off a calibrated severity of the knock event. This retarded spark advance is used in the next ignition event to prevent further knock events. If knock continues, an additional amount of short term spark advance retard is added. When knock stops, short term knock spark retard is eliminated, the long term knock spark retard is reduced by a calibrated amount to recover some previously retarded spark advance. This decreases spark retard to improve engine performance.

The Crankshaft Position (CKP) Sensor circuits consist of a Powertrain Control Module (PCM) supplied 5-Volt reference circuit, low reference circuit and an output signal circuit. The CKP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel on the crankshaft. Each tooth on the tone wheel is spaced with missing teeth for the reference gap. The CKP Sensor produces an ON/OFF DC voltage of varying frequency, reference output pulses per crankshaft revolution. The frequency of the CKP Sensor output depends on the velocity of the crankshaft. The CKP Sensor sends a digital signal, which represents an image of the crankshaft tone wheel, to the PCM as each tooth on the wheel rotates past the CKP Sensor. The PCM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft tone wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CKP Sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire and to control the CMP actuator if equipped.

The Crankshaft Position (CKP) Sensor circuits consist of a Powertrain Control Module (PCM) supplied 5-Volt reference circuit, low reference circuit and an output signal circuit. The CKP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel on the crankshaft. Each tooth on the tone wheel is spaced with missing teeth for the reference gap. The CKP Sensor produces an ON/OFF DC voltage of varying frequency, reference output pulses per crankshaft revolution. The frequency of the CKP Sensor output depends on the velocity of the crankshaft. The CKP Sensor sends a digital signal, which represents an image of the crankshaft tone wheel, to the PCM as each tooth on the wheel rotates past the CKP Sensor. The PCM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft tone wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CKP Sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire and to control the CMP actuator if equipped.

The Camshaft Position (CMP) Sensor circuits consist of an Powertrain Control Module (PCM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel attached to the camshaft. As each tooth rotates past the CMP Sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency output pulses per Camshaft revolution that represent an image of the camshaft tone wheel. The frequency of the CMP Sensor output depends on the velocity of the camshaft. The PCM decodes the tooth pattern to identify camshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CMP Sensor output information to determine the camshaft relative position to the Crankshaft, to control the CMP Actuator operation if equipped.

The Camshaft Position (CMP) Sensor circuits consist of an Powertrain Control Module (PCM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel attached to the camshaft. As each tooth rotates past the CMP Sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency output pulses per Camshaft revolution that represent an image of the camshaft tone wheel. The frequency of the CMP Sensor output depends on the velocity of the camshaft. The PCM decodes the tooth pattern to identify camshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CMP Sensor output information to determine the camshaft relative position to the Crankshaft, to control the CMP Actuator operation if equipped.

The State of Change (SOC) catalyst monitor uses the signals from both the upstream and downstream O2 Sensors to detect aging of the catalyst. Based on the fact that when a catalyst ages, it loses some of its Oxygen Storage Capacity (OSC). As a result, part of the untreated exhaust gases can breakthrough the catalyst and causes the downstream O2 Sensor to deviate from its neutral (Stoichiometric) position. By observing the activities in the downstream O2 Sensor signal, located in the exhaust path behind the Catalytic Converter, the degradation level of catalyst can be detected. In general, the higher the downstream O2 Sensor SOC value, the more exhaust gas breakthrough and the lower the Oxygen Storage Capacity of the Catalytic Converter. The Downstream O2 Sensor response monitor is intended to diagnose a Downstream O2 Sensor that is not moving or stuck in a voltage window and to insure accurate information for catalyst monitor diagnosis.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. At key off, the Powertrain Control Module (PCM) monitors the Evaporative System Integrity Monitor (ESIM) Switch. As the fuel and air in the Fuel Tank cools, a vacuum will occur naturally inside the tank. One inch of vacuum will cause the switch to close. If the PCM sees the switch close before the counter reaches a calibrated amount, the monitor passes.

The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. With the engine running, the monitor will first evaluate the delta pressure change of the Fuel Tank Pressure (FTP) Sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. The intrusive test runs only if stage one does not pass. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.

Fuel level is recorded when the ignition key is turned off and is compared to the fuel level when the ignition key is turned back on. The Powertrain Control Module (PCM) recognizes an increase in fuel level and will fail the Medium leak test because the fuel cap is broken or not installed properly. GAS CAP will be displayed to inform the owner that the cap is off or loose.

The Fuel Level Sensor information is a bussed message to the Powertrain Control Module (PCM) from the Body Control Module (BCM). The fuel level rationality will set a fault for a fuel level reading that does not change over an accumulated mileage threshold to keep stuck high or stuck low fuel levels from disabling OBD monitors. If the vehicle is fitted with a saddle tank fuel system this feature includes diagnostics for both of the sending units and diagnostics for a siphon tube that has become disconnected or plugged. The power up test looks to see a large enough fuel level voltage change from the last key-off to the following engine run. The engine run test looks to see a fuel level voltage change over an accumulated mileage.

Vehicles fitted with saddle fuel tank configurations have two Fuel Level Sensors. The primary side of the tank has the filler tube inlet near the bottom and contains the Fuel Pump Module. During fuel tank fills, fuel must overflow the primary side to reach the secondary side of the tank. As fuel is consumed, a siphon tube is used to draw fuel from the secondary side to the primary side. Because the siphon tube flow rate exceeds the fuel consumption rate, the secondary side of the tank will be empty before fuel is depleted from the primary side. Fuel Level Sensor 1 is located on the primary side of the tank. Fuel Level Sensor 2 is located on the secondary side of the tank.

The Fuel Level Sensor information is a bussed message to the Powertrain Control Module (PCM) from the Body Control Module (BCM). The fuel level rationality will set a fault for a fuel level reading that does not change over an accumulated mileage threshold to keep stuck high or stuck low fuel levels from disabling OBD monitors. If the vehicle is fitted with a saddle tank fuel system this feature includes diagnostics for both of the sending units and diagnostics for a siphon tube that has become disconnected or plugged. The power up test looks to see a large enough fuel level voltage change from the last key-off to the following engine run. The engine run test looks to see a fuel level voltage change over an accumulated mileage.

Vehicles fitted with saddle fuel tank configurations have two Fuel Level Sensors. The primary side of the tank has the filler tube inlet near the bottom and contains the Fuel Pump Module. During fuel tank fills, fuel must overflow the primary side to reach the secondary side of the tank. As fuel is consumed, a siphon tube is used to draw fuel from the secondary side to the primary side. Because the siphon tube flow rate exceeds the fuel consumption rate, the secondary side of the tank will be empty before fuel is depleted from the primary side. Fuel Level Sensor 1 is located on the primary side of the tank. Fuel Level Sensor 2 is located on the secondary side of the tank.

The Fuel Level Sensor information is a bussed message to the Powertrain Control Module (PCM) from the Body Control Module (BCM). The fuel level rationality will set a fault for a fuel level reading that does not change over an accumulated mileage threshold to keep stuck high or stuck low fuel levels from disabling OBD monitors. If the vehicle is fitted with a saddle tank fuel system this feature includes diagnostics for both of the sending units and diagnostics for a siphon tube that has become disconnected or plugged. The power up test looks to see a large enough fuel level voltage change from the last key-off to the following engine run. The engine run test looks to see a fuel level voltage change over an accumulated mileage.

Vehicles fitted with saddle fuel tank configurations have two Fuel Level Sensors. The primary side of the tank has the filler tube inlet near the bottom and contains the Fuel Pump Module. During fuel tank fills, fuel must overflow the primary side to reach the secondary side of the tank. As fuel is consumed, a siphon tube is used to draw fuel from the secondary side to the primary side. Because the siphon tube flow rate exceeds the fuel consumption rate, the secondary side of the tank will be empty before fuel is depleted from the primary side. Fuel Level Sensor 1 is located on the primary side of the tank. Fuel Level Sensor 2 is located on the secondary side of the tank.

The Radiator Fan Module is a smart device which controls the PCM Radiator Fan speed. The Radiator Fan Module receives a continuous wake-up signal from the Radiator Fan Relay output. The Powertrain Control Module (PCM) controls the Radiator Fan Relay via a LSD to close the relay an turn on the wake-up signal. The PCM communicates with the Radiator Fan Module through a Pulse-Width Modulated (PWM) signal. The PCM communicates the desired fan speed using the PWM circuit. The PWM Radiator Fan can be operated between 10% duty cycle (Low speed) and 92% duty cycle (High speed). The Radiator Fan Module relays internal fault messages to the PCM using the same PWM circuit.

If the wake-up signal between the Radiator Fan Relay and the Radiator Fan Module is lost after Radiator Fan Module is initialized, the fan defaults to high speed.

The Radiator Fan Module is a smart device which controls the PCM Radiator Fan speed. The Radiator Fan Module receives a continuous wake-up signal from the Radiator Fan Relay output. The Powertrain Control Module (PCM) controls the Radiator Fan Relay via a LSD to close the relay an turn on the wake-up signal. The PCM communicates with the Radiator Fan Module through a Pulse-Width Modulated (PWM) signal. The PCM communicates the desired fan speed using the PWM circuit. The PWM Radiator Fan can be operated between 10% duty cycle (Low speed) and 92% duty cycle (High speed). The Radiator Fan Module relays internal fault messages to the PCM using the same PWM circuit.

If the wake-up signal between the Radiator Fan Relay and the Radiator Fan Module is lost after Radiator Fan Module is initialized, the fan defaults to high speed.

The vehicle speed sensor rationality is a continuous test that monitors the vehicle speed sensor for lack of activity. The rationality will not run if a limp-in exists for MAP, Throttle Position, Crankshaft Sensor, Camshaft Sensor, and Engine Coolant Temperature. If vehicle speed sensor is below a minimum threshold for a period of time after the vehicle is operated at a sufficient load, a failure will be indicated.

See also:
• STANDARD PROCEDURE
• BODY CONTROL MODULE (BCM) - DIAGNOSTIC CODE INDEX