2.0L - Dtcs B104D to P0461: 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.

Dual Variable Valve Timing (VVT) allows the Powertrain Control Module (PCM) to monitor and adjust the position of each camshaft, based on desired torque levels and engine operating conditions. The PCM controls two solenoid operated control valves, one for each camshaft, that are used to direct oil pressure to hydraulic actuators mounted between each camshaft and its driving sprocket. The oil pressure alters the angular position or phasing of each camshaft relative to crankshaft rotation. A sensor is used to monitor the position of each camshaft.

Dual Variable Valve Timing (VVT) allows the PCM to monitor and adjust the position of each camshaft, based on desired torque levels and engine operating conditions. The PCM controls two solenoid operated control valves, one for each camshaft, that are used to direct oil pressure to hydraulic actuators mounted between each camshaft and its driving sprocket. The oil pressure alters the angular position or phasing of each camshaft relative to crankshaft rotation. A sensor is used to monitor the position of each camshaft.

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 Air Temperature, Engine Coolant Temperature 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 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.

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 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 Powertrain Control Module (PCM) performs a continuous check of the O2 sensor heater circuit during operation. The heater circuit is momentarily disabled to allow a resistance measurement to be taken to calculate 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.

The Powertrain Control Module (PCM) performs a continuous check of the O2 sensor heater circuit during operation. The heater circuit is momentarily disabled to allow a resistance measurement to be taken to calculate 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.

The fuel feedback system will maintain a stoiciometric fuel/air mixture, 14.7:1, by modifying the injector pulse width according to the oxygen content of the exhaust gas. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoiciometric 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.

The fuel feedback system will maintain a stoiciometric fuel/air mixture, 14.7:1, by modifying the injector pulse width according to the oxygen content of the exhaust gas. The Powertrain Control Module (PCM) makes short term and long term fuel corrections to maintain stoiciometric 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.

The Powertrain Control Module (PCM) compares Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), and Ambient Air Temperature (AAT) under cold start conditions. Following a start to run delay time, the sensor values are compared. If the one sensor value is not within a specified range of the other two sensors, the value is determined to be irrational. Once the general temperature rationality is passed, the PCM determines that the general temperature sensor values are correct. The PCM compares the Engine Oil Temperature Sensor value to a threshold based on the other temp sensor values. If the difference is greater than a calibrated value, the diagnostic fails.

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.

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 catalyst monitor uses the signals from both the Upstream and Downstream O2 Sensors to detect aging of the catalyst. As a catalyst ages, it loses some of its oxygen storing capacity. As a result, part of the untreated exhaust gases can break through the catalyst and causes the Downstream O2 Sensor to deviate from its neutral (Stoichiometric) position. By observing the Downstream O2 Sensor signal, the degradation level of catalyst can be detected. In general, the higher the Downstream O2 Sensor state of change value, the more exhaust gas breakthrough and the lower the oxygen storage capacity of the catalytic converter.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor will be enabled under either a Small Leak test or it will run during a Large Leak test (This is when Small Leak test does not pass). During a Small Leak test, the monitor will first evaluate the delta pressure on 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. 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 Evap Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor is a two stage test and runs only after the Evap system passes the small leak test. Stage one is non-intrusive. The Powertrain Control Module (PCM) monitors the purge vapor ratio and the Evaporative System Integrity Monitor (ESIM) Switch closed ratio. If the purge vapor ratio is above a calculated value, the monitor passes. If the ESIM switch closed ratio is greater than calculated value when purge flow is greater than a minimum value, the monitor passes. Stage two is an intrusive test and runs only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is compared to a calibrated specification. If it is less than specified, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed, or the purge valve is not operational.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor will be enabled under either a Small Leak test or it will run during a Large Leak test (This is when Small Leak test does not pass). During a Small Leak test, the monitor will first evaluate the delta pressure on 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. 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. The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. The Powertrain Control Module (PCM) monitors the purge vapor ratio and the Evaporative System Integrity Monitor (ESIM) switch closed ratio. If the purge vapor ratio is above a calculated value, the monitor passes. If the ESIM switch closed ratio is greater than calculated value when purge flow is greater than a minimum value, the monitor passes. Stage two is an intrusive test and runs only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is compared to a calibrated specification. If it is less than specified, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed or the purge valve is not operational.

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. The Powertrain Control Module (PCM) monitors the purge vapor ratio and the Evaporative System Integrity Monitor (ESIM) switch closed ratio. If the purge vapor ratio is above a calculated value, the monitor passes. If the ESIM switch closed ratio is greater than calculated value when purge flow is greater than a minimum value, the monitor passes. Stage two is an intrusive test and runs only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is compared to a calibrated specification. If it is less than specified, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed or the purge valve is not operational.

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.

See also:
• STANDARD PROCEDURE