Description
Several states require that a vehicle pass On-Board Diagnostic (OBD) system tests and the Inspection/Maintenance (I/M) emission inspection in order to renew license plates. This is accomplished by viewing the I/M system status display on a scan tool. Using a scan tool, the I/M system status can observed in order to verify that the vehicle meets the criteria that complies with local area requirements.
Purpose of this test is to satisfy enable criteria necessary to execute all Inspection/Maintenance (I/M) readiness diagnostics, and to complete the trips (drive cycles) for those particular diagnostics. When all diagnostic tests have been completed, I/M system status indicators are set to YES. Perform this test when more than one or all of the I/M system status indicators are set to NO.
Purpose of this test is to satisfy the enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for the Secondary Air Injection (AIR) system. Test may be used to set the I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Purpose of this test is to satisfy enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for the catalyst system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Purpose of this test is to satisfy enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for the Exhaust Gas Recirculation (EGR) system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Purpose of this test is to satisfy enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for the Evaporative Emission (EVAP) system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Purpose of this test is to satisfy enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for Heated Oxygen Sensor/Oxygen Sensor (HO2S/O2S) system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Purpose of this test is to satisfy enable criteria necessary to execute Inspection/Maintenance (I/M) readiness diagnostics for Heated Oxygen Sensor (HO2S) heater system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets conditions listed in enable criteria before performing procedure. Failure to meet any of the conditions listed may produce inaccurate test results. See ENABLE CRITERIA .
Data Link Connector (DLC) provides operating power for scan tool through terminal No. 16 (Orange wire) and ground through terminal No. 4 (Black wire). DLC provides class 2 serial data signal through terminal No. 2 (Purple wire) and ground through terminal No. 5 (Black/White wire). Scan tool will power up with ignition off.
Heated Oxygen Sensor (HO2S) bank 1 sensor 1 heater is used to reduce the time that it takes for HO2S to go active. HO2S bank 1 sensor 1 is powered directly from the ignition 1 circuit. The Powertrain Control Module (PCM) controls HO2S heater operation by grounding the control circuit via an internal solid state device called a driver. The driver for HO2S bank 1 sensor 1 heater control circuit has the ability to measure the amount of current drawn by HO2S heater. If PCM detects HO2S bank 1 sensor 1 heater control circuit current is outside of calibrated range, DTC P0030 will set.
Heated Oxygen Sensor (HO2S) bank 1 sensor 2 heater is used to reduce the time that it takes for HO2S to go active. HO2S bank 1 sensor 2 is powered directly from the ignition 1 circuit. The Powertrain Control Module (PCM) controls HO2S heater operation by grounding the control circuit via an internal solid state device called a driver. Primary function of the driver is to supply ground for HO2S bank 1 sensor 2 heater. If PCM detects HO2S bank 1 sensor 2 heater control circuit current is outside of calibrated range, DTC P0036 will set.
Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering engine. Powertrain Control Module (PCM) uses MAF sensor signal to provide correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit and a signal circuit. The PCM applies a voltage to MAF sensor on the signal circuit. MAF sensor uses the voltage to produce a frequency based on inlet airflow through the sensor bore. The PCM uses barometric pressure, air density, manifold pressure, throttle position, and engine RPM to calculate a predicted MAF sensor value. The PCM compares actual MAF sensor signal to the predicted MAF value to determine if signal is stuck based on a lack of variation, or is too low, or too high for a given operating condition. DTC P0101 will set if actual MAF sensor signal is not within a predetermined range of calculated MAF value.
Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering engine. Powertrain Control Module (PCM) uses MAF sensor signal to provide correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering engine indicates deceleration or idle. A large quantity of air entering engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, ground circuit and a signal circuit. The PCM applies a voltage to MAF sensor on the signal circuit. MAF sensor uses the voltage to produce a frequency based on inlet airflow through the sensor bore. The frequency will vary within a range of about 2000 Hz at idle to about 10,500 Hz at maximum engine load. DTC P0102 will set if PCM detects a frequency signal lower than the possible range of a normally operating MAF sensor.
Mass Airflow (MAF) sensor is an airflow meter that measures the amount of air entering engine. Powertrain Control Module (PCM) uses the MAF sensor signal to provide correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering engine indicates deceleration or idle. A large quantity of air entering engine indicates an acceleration or high load situation. MAF sensor has an ignition 1 voltage circuit, ground circuit and a signal circuit. The PCM applies a voltage to MAF sensor on the signal circuit. MAF sensor uses the voltage to produce a frequency based on inlet airflow through the sensor bore. The frequency will vary within a range of about 2000 Hz at idle to about 10,500 Hz at maximum engine load. DTC P0103 will set if PCM detects a frequency signal higher than the possible range of a normally operating MAF sensor.
Manifold Absolute Pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on engine load. Powertrain Control Module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during idle or deceleration. The PCM should detect a high signal voltage at a high MAP, such as with ignition on or at Wide Open Throttle (WOT). MAP sensor value is also used to determine the Barometric Pressure (BARO). This occurs when ignition is on. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range. DTC P0107 will set when MAP sensor voltage is less than .1 volt for at least 10 seconds.
Manifold Absolute Pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on engine load. Powertrain Control Module (PCM) supplies 5 volts to MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during idle or deceleration. The PCM should detect a high signal voltage at a high MAP, such as when ignition is on or at a Wide Open Throttle (WOT). MAP sensor value is also used to determine the Barometric Pressure (BARO). This occurs when ignition is on. The BARO reading may also be updated whenever engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range. DTC P0108 will set when PCM detects MAP sensor signal voltage is excessively high.
Intake Air Temperature (IAT) sensor is a thermistor that measures temperature of air entering the engine. IAT sensor is located in air intake passage of engine air induction system. The Powertrain Control Module (PCM) supplies 5 volts to the IAT sensor signal circuit through a pull-up resistor. When intake air is cold, the PCM detects a high voltage on the IAT sensor signal circuit. As the intake air warms, the PCM detects a lower voltage on the IAT sensor signal circuit. The IAT sensor is a thermistor that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC P0112 will set if PCM detects an excessively low IAT sensor signal voltage (high temperature indicated).
Intake Air Temperature (IAT) sensor is a thermistor that measures temperature of air entering the engine. IAT sensor is located in air intake passage of engine air induction system. The Powertrain Control Module (PCM) supplies 5 volts to the IAT sensor signal circuit through a pull-up resistor. When intake air is cold, the PCM detects a high voltage on the IAT sensor signal circuit. As the intake air warms, the PCM detects a lower voltage on the IAT sensor signal circuit. The IAT sensor is a thermistor that varies resistance based on temperature. As temperature of sensor increases, resistance decreases. High temperature will result in a low signal voltage. DTC P0113 will set if PCM detects an excessively high IAT sensor signal voltage (low temperature indicated).
Engine Coolant Temperature (ECT) sensor is a thermistor that measures temperature of engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the ECT sensor signal circuit through a pull-up resistor. When engine coolant temperature is cold, ECT sensor resistance is high. When engine coolant temperature increases, ECT sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT sensor signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT sensor signal circuit. DTC P0117 will set if PCM detects an excessively low signal voltage.
Engine Coolant Temperature (ECT) sensor is a thermistor that measures temperature of the engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the ECT sensor signal circuit through a pull-up resistor. When engine coolant temperature is cold, ECT sensor resistance is high. When engine coolant temperature increases, ECT sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT sensor signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT sensor signal circuit. DTC P0118 will set if PCM detects an excessively high signal voltage
Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from closed throttle position to Wide Open Throttle (WOT) position provides PCM with a signal voltage from less than one volt to more than 4 volts through the TP sensor signal circuit. When conditions for running this DTC are met, the PCM will use the Manifold Absolute Pressure (MAP) sensor to determine if the predicted operating range of the TP Sensor is correct. A skewed MAP sensor may cause DTC P0121 to set and should be tested for proper operation if TP sensor is determined to be operating properly and this DTC continues to set.
Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from closed throttle position to Wide Open Throttle (WOT) position provides PCM with a signal voltage from less than one volt to more than 4 volts through the TP sensor signal circuit. DTC P0122 will set if PCM detects an excessively low signal voltage.
Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from closed throttle position to Wide Open Throttle (WOT) position provides the PCM with a signal voltage from less than one volt to more than 4 volts through TP sensor signal circuit. DTC P0123 will set if PCM detects an excessively high signal voltage.
Engine Coolant Temperature (ECT) sensor monitors temperature of coolant. This input is used by the Powertrain Control Module (PCM) for engine control and as an enabling criteria for some diagnostics. If engine coolant temperature does not increase normally or does not reach regulating temperature of thermostat, diagnostics that use the ECT as an enabling criteria may not run when expected. DTC P0125 will set if an excessive amount of time passes before engine coolant temperature reaches closed loop operating temperature.
Heated Oxygen Sensor (HO2S) is used to detect oxygen content in the exhaust. The Powertrain Control Module (PCM) supplies HO2S with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The HO2S varies voltage based on oxygen content in the exhaust. When exhaust stream is lean (more oxygen), HO2S produces a low voltage signal. When exhaust stream is rich (less oxygen), HO2S produces a high voltage signal. The PCM monitors HO2S signal during closed loop. To correct for rich or lean conditions, PCM adjusts injector pulse width. DTC P0130 will set if HO2S bank 1 sensor 1 signal voltage remains within a calibrated range for about 16 seconds during 120 second monitoring period.
Heated Oxygen Sensor (HO2S) is used to detect oxygen content in the exhaust. The Powertrain Control Module (PCM) supplies HO2S with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The HO2S varies voltage based on oxygen content in the exhaust. When exhaust stream is lean (more oxygen), HO2S produces a low voltage signal. When exhaust stream is rich (less oxygen), HO2S produces a high voltage signal. The PCM monitors HO2S signal during closed loop. To correct for rich or lean conditions, PCM adjusts injector pulse width. DTC P0131 will set if HO2S bank 1 sensor 1 signal voltage remains less than 175 millivolts for about 50 seconds during normal closed loop fuel control. DTC will also set if HO2S bank 1 sensor 1 signal voltage remains at less than 600 millivolts during power enrichment fuel control.
Heated Oxygen Sensor (HO2S) is used to detect oxygen content in the exhaust. The Powertrain Control Module (PCM) supplies HO2S with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The HO2S varies voltage based on oxygen content in the exhaust. When exhaust stream is lean (more oxygen), HO2S produces a low voltage signal. When exhaust stream is rich (less oxygen), HO2S produces a high voltage signal. The PCM monitors the HO2S signal during closed loop. To correct for rich or lean conditions, PCM adjusts injector pulse width. DTC P0132 will set if HO2S bank 1 sensor 1 signal voltage remains more than 975 millivolts for about 50 seconds during normal closed loop fuel control. DTC will also set if HO2S bank 1 sensor 1 signal voltage remains at more than 200 millivolts during deceleration fuel control.
The Powertrain Control Module (PCM) continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitoring period, the PCM counts the number of rich to lean and lean to rich transitions and adds the amount of time it took to complete all transitions. With this information, an average time for each transition can be determined. If the average response time is too slow, a DTC P0133 will set. A lean to rich transition is indicated when HO2S voltage changes from less than 300 millivolts to more than 600 millivolts. A rich to lean transition is indicated when the HO2S voltage changes from more than 600 millivolts to less than 300 millivolts. An HO2S that responds too slowly is likely to be malfunctioning and should be replaced. DTC will set if HO2S bank 1 sensor 1 lean-to-rich or rich-to-lean average transition response time during the sample period is more than 220 milliseconds.
The Powertrain Control Module (PCM) supplies a bias voltage of about 450 millivolts between the Heated Oxygen Sensor (HO2S) high signal circuit and the HO2S low reference circuit. When measured with a 10 megohm digital voltmeter, this voltage may be as low as 350 millivolts. The HO2S high signal varies from about 800 millivolts when the exhaust is rich, to about 50 millivolts when the exhaust is lean. If HO2S bank 1 sensor 1 voltage remains at or near 450 millivolts bias for an extended period of time, DTC P0134 will set.
Heated Oxygen Sensors (HO2S) are used to minimize the amount of time required to enter closed loop fuel control operation and to allow accurate catalyst monitoring. The HO2S bank 1 sensor 1 heater is supplied power directly from ignition 1 circuit. The HO2S bank 1 sensor 1 heater control circuit or heater ground is connected to the Powertrain Control Module (PCM). The PCM controls HO2S heater operation by grounding the control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. The driver for the HO2S bank 1 sensor 1 heater control circuit has the ability to measure the amount of current drawn by the controlled device. DTC P0135 will set if PCM detects HO2S bank 1 sensor 1 voltage remains within 150 millivolts of bias voltage (about 450 millivolts) for more than a predetermined amount of time.
Powertrain Control Module (PCM) uses a 3-way catalytic converter to control hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx) emissions. The catalyst within the converter promotes a chemical reaction that oxidizes HC and CO present in the exhaust gas. After undergoing oxidation, the HC and CO are converted into harmless water vapor and carbon dioxide. The catalyst also reduces NOx emissions by converting the NOx into nitrogen. The PCM uses the heated oxygen sensors to monitor this process. HO2S bank 1 sensor 1 produces an output signal that indicates how much oxygen is present in the exhaust gas entering the 3-way catalytic converter. HO2S bank 1 sensor 2 produces an output signal that indicates the oxygen storage capacity of the catalyst. The oxygen storage capacity of the catalyst is a measure of the catalyst's ability to convert exhaust gases efficiently. If the catalyst is operating efficiently, the HO2S bank 1 sensor 1 signal will be more active than the HO2S bank 1 sensor 2 signal. DTC P0137 will set if HO2S bank 1 sensor 2 signal voltage remains less than 175 millivolts during normal closed loop operation or if signal voltage remains less than 600 millivolts during power enrichment mode fuel control operation for about 50 seconds.
Powertrain Control Module (PCM) supplies a bias voltage of about 450 millivolts between Heated Oxygen Sensor (HO2S) signal circuit and HO2S low reference circuit. When measured with a 10 megohm digital voltmeter, voltage may be as low as 350 millivolts. The HO2S sensor signal varies from about 800 millivolts when exhaust is rich, to about 50 millivolts when exhaust is lean. PCM constantly monitors HO2S signal during closed loop operation. The PCM then compensates for a rich or lean condition by decreasing or increasing the injector pulse width as necessary. DTC P0138 will set if HO2S bank 1 sensor 2 signal voltage remains more than 999 millivolts for about 50 seconds during normal closed loop fuel control or more than 200 millivolts during deceleration fuel mode operation.
The Powertrain Control Module (PCM) supplies a bias voltage of about 450 millivolts between the Heated Oxygen Sensor (HO2S) high signal circuit and the HO2S low reference circuit. When measured with a 10-megohm digital voltmeter, this voltage may be as low as 350 millivolts. The HO2S high signal varies from about 800 millivolts when the exhaust is rich, to about 50 millivolts when the exhaust is lean. If HO2S bank 1 sensor 2 voltage remains at or near 450 millivolts bias for an extended period of time, DTC P0140 will set
Heated Oxygen Sensors (HO2S) are used to minimize the amount of time required to enter closed loop fuel control operation and to allow accurate catalyst monitoring. The HO2S bank 1 sensor 2 heater is supplied power directly from ignition 1 circuit. The HO2S bank 1 sensor 2 heater control circuit or heater ground is connected to the Powertrain Control Module (PCM). The PCM controls HO2S heater operation by grounding the control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. The driver for the HO2S bank 1 sensor 2 heater control circuit has the ability to measure the amount of current drawn by the controlled device. DTC P0141 will set if PCM determines that too much time was required for sensor to become active.
Powertrain Control Module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during open loop and closed loop. During open loop the PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During closed loop the PCM adds oxygen sensor inputs to calculate short term and long term fuel trim (fuel delivery adjustments). If oxygen sensors indicate a lean condition, fuel trim values will be more than zero percent. If oxygen sensors indicate a rich condition, fuel trim values will be less than zero percent. Short term fuel trim values change rapidly in response to Heated Oxygen Sensor (HO2S) voltage signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. DTC P0171 will set if PCM detects an excessively lean condition.
Powertrain Control Module (PCM) controls air/fuel metering system in order to provide best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during open loop and closed loop. During open loop the PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During closed loop the PCM adds oxygen sensor inputs to calculate short term and long term fuel trim (fuel delivery adjustments). If oxygen sensors indicate a lean condition, fuel trim values will be more than zero percent. If oxygen sensors indicate a rich condition, fuel trim values will be less than zero percent. Short term fuel trim values change rapidly in response to Heated Oxygen Sensor (HO2S) voltage signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. Fuel trim diagnostic will conduct a test to determine if a rich condition actually exists or if excessive vapor from EVAP canister is causing a rich condition. DTC P0172 will set if PCM detects an excessively rich condition.
Powertrain Control Module (PCM) enables appropriate fuel injector on intake stroke for each cylinder. Ignition voltage is supplied to fuel injectors. The PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The PCM monitors driver state. DTC P0201-P0206 will set if PCM detects an incorrect voltage on fuel injector control circuit.
Powertrain Control Module (PCM) provides ignition voltage to coil side of fuel pump relay. When ignition is first turned on, PCM energizes fuel pump relay, which applies power to fuel pump. The PCM enables fuel pump relay as long as engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, PCM de-energizes fuel pump relay after 2 seconds. The PCM monitors voltage on fuel pump relay control circuit. DTC P0230 will set if PCM detects an incorrect voltage on fuel injector control circuit.
Crankshaft Position (CKP) sensor sends pulses to Powertrain Control Module (PCM) when the reluctor teeth rotate past the sensor. PCM uses the pulses to synchronize ignition and fuel injection operation. The PCM also measure interval between each pulse to determine if an excess change in crankshaft speed has occurred. A misfire causes an unwanted change in crankshaft speed. A certain amount of crankshaft acceleration or deceleration is expected between each firing stroke. If crankshaft speed changes are more than an expected amount, PCM will interpret this as a misfire. If 2 percent or more of all cylinder firing events are misfires, emission levels may exceed mandated standards. PCM monitors blocks of 200 engine revolutions and counts the number of misfires in each block. DTC P0300 will set if PCM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emission levels to exceed mandated standard.
Powertrain Control Module (PCM) uses a knock sensor to detect engine detonation, or spark knock. Knock sensor produces an AC signal at all engine speeds and loads. The PCM makes adjustments to spark timing based on the amplitude and frequency of knock sensor signal. The PCM uses the knock sensor to calculate amount of normal engine noise (a noise channel) for a wide range of engine speeds and loads. The PCM compares actual knock sensor signal to learned noise channel. DTC P0325 will set if PCM detects a malfunction in the integrated knock sensor diagnostic circuity that will not allow proper diagnosis of knock sensor system.
Powertrain Control Module (PCM) uses a knock sensor to detect engine detonation, or spark knock. Knock sensor produces an AC signal at all engine speeds and loads. The PCM makes adjustments to spark timing based on the amplitude and frequency of knock sensor signal. The PCM uses knock sensor signal to calculate the average voltage. Then, PCM assigns a voltage value. The PCM checks knock sensor and related wiring by comparing the actual knock signal to the assigned voltage range. A normal knock sensor signal should stay outside the assigned voltage range. DTC P0327 will set if PCM detects a knock sensor signal of less than .4 volt.
The Crankshaft Position (CKP) sensor is actually 2 sensors within a single housing. There are separate power, ground (reference low) and signal circuits connecting both sensors to the Powertrain Control Module (PCM). The PCM supplies 12 volts to the CKP sensor. The PCM can use 3 different modes of decoding crankshaft position. During normal operation, the PCM performs an angle based calculation using both signals to determine crankshaft position. The dual sensor allows the engine to run even if one signal is lost. If either signal is lost, the PCM switches to a time based method of calculating crankshaft position. If the system is operating in Time A mode, the PCM is using only the signal from sensor A. Time B indicates that the sensor B signal is being used. If the lost signal is restored, the PCM will continue to operate in Time A or B mode for the remainder of the current key cycle. The PCM will automatically revert back to the Angle mode on the next start-up if the fault is not present.
Powertrain Control Module (PCM) uses Camshaft Position (CMP) sensor high resolution signal to determine position of valve train in relation to engine cylinders. The PCM uses CMP high resolution signal to sequence the ignition system and fuel injectors. The PCM supplies a 12-volt reference and a low reference to the CMP sensor. The CMP sensor returns a signal pulse in response to the reluctor track, located on camshaft sprocket. If during operation, the PCM detects a loss of CMP sensor high resolution signal, DTC P0340 will set.
Powertrain Control Module (PCM) tests Exhaust Gas Recirculation (EGR) system during deceleration by momentarily commanding EGR valve open while monitoring Manifold Absolute Pressure (MAP) sensor signal. When EGR valve is opened, the PCM should see a proportional increase in MAP. If expected increase in MAP is not seen, PCM notes amount of error that was detected and adjusts an internal failure counter toward a failure threshold level. When failure counter exceeds failure threshold level, PCM will set DTC P0401.
Powertrain Control Module (PCM) monitors Exhaust Gas Recirculation (EGR) valve pintle position input to ensure valve responds properly to PCM commands. The linear EGR valve is controlled by using an ignition positive driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the EGR solenoid high control circuit or EGR low control circuit. If an electrical malfunction occurs, the driver signals the PCM to set DTC P0403.
Powertrain Control Module (PCM) monitors Exhaust Gas Recirculation (EGR) valve pintle position input to ensure valve responds properly to PCM commands. The PCM compares EGR position sensor with desired EGR position when valve is commanded open. If difference between EGR position sensor and desired EGR position is more than 20 percent, DTC P0404 will set.
Powertrain Control Module (PCM) monitors Exhaust Gas Recirculation (EGR) valve pintle position input to ensure valve responds properly to commands from PCM, and to detect a fault if EGR valve position signal circuit is open or shorted. If PCM detects an excessively low EGR valve position signal voltage, DTC P0405 will set.
Powertrain Control Module (PCM) activates the Secondary Air Injection (AIR) system by grounding both the AIR pump relay and the AIR vacuum control solenoid control circuits. This energizes AIR pump and AIR solenoid. Vacuum is then applied, opening the shutoff valves. AIR pump then forces filtered fresh air into the exhaust stream to accelerate catalyst operation. The PCM will run up to 3 diagnostic tests using the pre-catalyst HO2S voltage and short term fuel trim to diagnose the system. AIR system can be diagnosed during normal secondary air injection operation or the PCM can activate the system specifically for diagnostic purposes. If AIR system is operating properly, the Heated Oxygen Sensor (HO2S) voltage will decrease and the short term fuel trim will increase when system is activated.
Ignition voltage is supplied directly to the AIR solenoid. Powertrain Control Module (PCM) supplies the ground path to the AIR solenoid control circuit via an internal solid state device called a driver. Each drive has a fault line which is monitored by the PCM. When PCM commands AIR solenoid on, voltage on the control circuit should be about zero volts. When PCM commands AIR solenoid off, voltage on the control circuit should be battery voltage. If fault detection circuit senses a voltage other than when is expected, DTC P0412 will set.
Ignition voltage is supplied directly to the AIR solenoid. Powertrain Control Module (PCM) supplies the ground path to the AIR solenoid control circuit via an internal solid state device called a driver. Each drive has a fault line which is monitored by the PCM. When PCM commands AIR solenoid on, voltage on the control circuit should be about zero volts. When PCM commands AIR solenoid off, voltage on the control circuit should be battery voltage. If fault detection circuit senses a voltage other than when is expected, DTC P0418 will set.
The catalyst with the catalytic converter promotes a chemical reaction with oxidizes Hydrocarbons (HC) and Carbon Monoxide (CO) that is present in the exhaust gas. This reaction converts the compounds into harmless water vapor and in carbon dioxide. The catalyst will also convert the Oxides of Nitrogen (NOx) into nitrogen. Powertrain Control Module (PCM) monitors this process via the signal from Heated Oxygen Sensor (HO2S) bank 1 sensor 1. HO2S bank 1 sensor 1 produces an output signal which indicates oxygen storage capacity or the catalyst. Oxygen storage capacity is one method of determining the catalyst's ability to convert exhaust emissions effectively. If catalyst is functioning correctly, HO2S bank 1 sensor 2 will be less active than HO2S bank 1 sensor 1 signal. If PCM detects excess HO2S bank 1 sensor 2 signal activity for an extended period of time, DTC P0420 will set.
Evaporative Emission (EVAP) large leak test applies vacuum to EVAP system and monitors vacuum decay. The Powertrain Control Module (PCM) monitors Fuel Tank Pressure (FTP) sensor signal to determine vacuum decay rate. At an appropriate time, the PCM turns EVAP canister purge valve on (open) and EVAP canister vent valve on (closed). This allows engine to draw a vacuum on EVAP system. At a calibrated time, or vacuum level, the PCM turns purge valve off (closed), sealing the system, and monitors FTP sensor input to determine EVAP system vacuum. If system is unable to achieve calibrated vacuum level, or if vacuum level decreases too rapidly, DTC P0440 will set.
This DTC tests Evaporative Emission (EVAP) system for a small leak. Powertrain Control Module (PCM) monitors Fuel Tank Pressure (FTP) sensor signal to determine vacuum decay rate. At an appropriate time, PCM turns EVAP canister purge valve and EVAP canister vent valve on. This allows engine to draw a vacuum on EVAP system. At a calibrated time, or vacuum level, PCM turns EVAP canister purge valve off, sealing the system, and monitors FTP sensor input to determine EVAP system vacuum decay. If PCM detects a leak larger than calibrated amount, DTC P0442 will set.
Powertrain Control Module (PCM) uses Output Driver Modules (ODM) to control many functions of the engine and transaxle. The ODMs supply the ground path for the PCM controlled device when the PCM commands the device on. Each ODM is able to control several outputs. Unlike Quad Driver Modules (QDM) used in earlier model years, the ODMs are able to diagnose each output circuit. The PCM monitors the ODMs for circuit conditions that are incorrect for commanded state of the ODM. If PCM detects an improper circuit condition in the ODM that controls EVAP purge solenoid valve, DTC P0443 will set.
This DTC tests Evaporative Emission (EVAP) system for a restricted or blocked EVAP vent path. Powertrain Control Module (PCM) commands EVAP canister purge valve and EVAP canister vent valve on. This allows a vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the PCM commands EVAP canister purge valve and EVAP canister vent valve off. The PCM monitors Fuel Tank Pressure (FTP) sensor for a decrease in vacuum. If vacuum does not decrease to near zero in. H2O in a calibrated time, DTC P0446 will set.
An ignition voltage is supplied directly to Evaporative Emission (EVAP) canister vent valve. Powertrain Control Module (PCM) controls EVAP vent valve by grounding control circuit via an internal switch called a driver. Primary function of the driver is to supply ground for the controlled component. The PCM monitors driver status. If PCM detects an incorrect voltage for commanded state of the driver, DTC P0449 will set.
Fuel Tank Pressure (FTP) sensor measures pressure or vacuum in the fuel tank. The Powertrain Control Module (PCM) supplies a 5-volt reference and a low reference circuit to FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If PCM detects FTP sensor signal voltage goes to less than calibrated value, DTC P0452 will set.
Fuel Tank Pressure (FTP) sensor measures pressure or vacuum in fuel tank. The Powertrain Control Module (PCM) supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If PCM detects FTP sensor signal voltage goes to more than calibrated value, DTC P0453 will set.
Idle Air Control (IAC) valve is located on throttle body. IAC valve consists of a movable pintle, driven by a gear attached to an electric motor called a stepper motor. The IAC valve motor is a 2 phase bi-polar permanent magnet stepper motor that is capable of highly accurate rotation, or movement, every time polarity of a winding is changed. Polarity can be seen when observing a test light connected between ground or B+ and an IAC valve circuit while the Powertrain Control Module (PCM) is attempting to change engine RPM (test light will flash on or off each time polarity is changed). The PCM does not use a physical sensor to determine IAC pintle position, but uses a predicted number of counts, one count represents one change in polarity which equals one step of the stepper motor. The PCM counts the steps it has commanded to determine IAC pintle position. The PCM uses IAC valve to control engine idle speed. It does this by changing pintle position in the idle air passage of the throttle body. This varies airflow around throttle plate when throttle is closed. To determine desired position of IAC pintle at idle or during deceleration, the PCM refers to the following inputs: engine RPM, battery voltage, air temperature, engine coolant temperature, throttle position sensor angle, engine load, and vehicle speed. When ignition is turned off after an ignition cycle, the PCM will first seat the IAC pintle in the air by-pass bore, and then retract it a predetermined amount of counts to allow proper amount of air to by-pass throttle plate for engine start-up. This procedure is known as an IAC reset.
Powertrain Control Module (PCM) monitors system voltage to make sure that voltage stays within the proper range. Damage to components and incorrect data input can occur when voltage is out of range. PCM monitors system voltage over an extended length of time. If PCM detects a system voltage out of an expected range for the calibrated length of time, DTC P0560 will set.
Powertrain Control Module (PCM) monitors system voltage to make sure that voltage stays within the proper range. Damage to components and incorrect data input can occur when voltage is out of range. PCM monitors system voltage over an extended length of time. If PCM detects an excessively low system voltage, DTC P0562 will set.
Powertrain Control Module (PCM) monitors system voltage to make sure that voltage stays within the proper range. Damage to components and incorrect data input can occur when voltage is out of range. PCM monitors system voltage over an extended length of time. If PCM detects an excessively high system voltage, DTC P0563 will set.
Powertrain Control Module (PCM) uses an Electrically Erasable Programmable Read Only Memory (EEPROM). The EEPROM contains program information and calibrations required for powertrain diagnostics operation. Unlike Programmable Read Only Memory (PROM) used in past applications, the EEPROM is not replaceable. When PCM is replaced or a calibration update is required, PCM must be programmed. DTC P0601 will set if PCM detects a problem with internal programming.
Powertrain Control Module (PCM) uses an Electrically Erasable Programmable Read Only Memory (EEPROM) to store software and calibration information. EEPROM is not replaceable, PCM must be replaced. Replacement PCM does not contain final program information. Replacement PCM must be programed. If replacement PCM is not programmed, DTC P0602 will set.
Ignition voltage is supplied directly to the Malfunction Indicator Light (MIL). The Powertrain Control Module (PCM) controls the MIL by grounding the control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground circuit. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, voltage of the control circuit should be near zero volts. When the PCM is commanding a component off, voltage potential of the circuit should be near battery voltage. If the fault detection circuit senses a voltage other than what is expected, DTC P0650 will set.
Manifold Absolute Pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on engine load. Powertrain Control Module (PCM) supplies 5 volts to MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during idle or deceleration. The PCM should detect a high signal voltage at a high MAP, such as when ignition is on or at a Wide Open Throttle (WOT). MAP sensor value is also used to determine the Barometric Pressure (BARO). This occurs when ignition is on. The BARO reading may also be updated whenever engine is operated at WOT. The PCM monitors MAP sensor signal for voltage outside of the normal range. DTC P1106 will set when PCM detects MAP sensor signal voltage is intermittently high.
Manifold Absolute Pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on engine load. Powertrain Control Module (PCM) supplies 5 volts to MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during idle or deceleration. The PCM should detect a high signal voltage at a high MAP, such as when ignition is on or at a Wide Open Throttle (WOT). MAP sensor value is also used to determine the Barometric Pressure (BARO). This occurs when ignition is on. The BARO reading may also be updated whenever engine is operated at WOT. The PCM monitors MAP sensor signal for voltage outside of the normal range. DTC P1107 will set when PCM detects MAP sensor signal voltage is intermittently low.
Intake Air Temperature (IAT) sensor contains a semiconductor device which changes resistance based on temperature. The IAT sensor is located in the air intake passage of the engine air induction system. IAT sensor has a signal circuit and a ground circuit. The Powertrain Control Module (PCM) applies about 5 volts on the signal circuit to the IAT sensor. The PCM monitors changes in this voltage caused by changes in resistance of sensor to determine intake air temperature. When intake air is cold, sensor resistance is high, and PCM signal voltage is only pulled down a small amount through the sensor to ground. Therefore, the PCM will sense a high signal voltage or a low temperature. When intake air is warm, sensor resistance is low, and signal voltage is pulled down a greater amount. Therefore the PCM will sense a low signal voltage or a high temperature. If PCM detects an excessively high IAT signal voltage intermittently, (a low temperature indication), DTC P1111 will set.
Intake Air Temperature (IAT) sensor contains a semiconductor device which changes resistance based on temperature. The IAT sensor is located in the air intake passage of the engine air induction system. IAT sensor has a signal circuit and a ground circuit. The Powertrain Control Module (PCM) applies about 5 volts on the signal circuit to the IAT sensor. The PCM monitors changes in this voltage caused by changes in resistance of sensor to determine intake air temperature. When intake air is cold, sensor resistance is high, and PCM signal voltage is only pulled down a small amount through the sensor to ground. Therefore, the PCM will sense a high signal voltage or a low temperature. When intake air is warm, sensor resistance is low, and signal voltage is pulled down a greater amount. Therefore the PCM will sense a low signal voltage or a high temperature. If PCM detects an excessively low IAT signal voltage intermittently, (a high temperature indication), DTC P1112 will set.
Engine Coolant Temperature (ECT) sensor is a thermistor that measures temperature of engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the ECT sensor signal circuit through a pull-up resistor. When engine coolant temperature is cold, ECT sensor resistance is high. When engine coolant temperature increases, ECT sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT sensor signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT sensor signal circuit. DTC P1114 will set if PCM detects an excessively low signal voltage (high temperature indication).
Engine Coolant Temperature (ECT) sensor is a thermistor that measures temperature of engine coolant. The Powertrain Control Module (PCM) supplies 5 volts to the ECT sensor signal circuit through a pull-up resistor. When engine coolant temperature is cold, ECT sensor resistance is high. When engine coolant temperature increases, ECT sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT sensor signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT sensor signal circuit. DTC P1115 will set if PCM detects an excessively high signal voltage (low temperature indication).
Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from closed throttle position to Wide Open Throttle (WOT) position provides the PCM with a signal voltage from less than one volt to more than 4 volts through TP sensor signal circuit. DTC P1121 will set if PCM detects an intermittent excessively high signal voltage.
Throttle Position (TP) sensor is used by the Powertrain Control Module (PCM) to determine throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM provides TP sensor with a 5-volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from closed throttle position to Wide Open Throttle (WOT) position provides the PCM with a signal voltage from less than one volt to more than 4 volts through TP sensor signal circuit. DTC P1122 will set if PCM detects an intermittent excessively low signal voltage.
Powertrain Control Module (PCM) continuously monitors Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitor period, PCM counts the number of times HO2S transitions from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. PCM then divides rich to lean average by the lean to rich average to obtain a ratio. If the HO2S transition time ratio is not within range, DTC P1133 will set, indicating oxygen sensor is not responding as expected to changes in exhaust oxygen content.
Heated Oxygen Sensor (HO2S) is used to detect oxygen content in the exhaust. The Powertrain Control Module (PCM) supplies HO2S with a signal circuit and a ground circuit. The PCM supplies a bias voltage between the circuits. The HO2S varies voltage based on oxygen content in the exhaust. When exhaust stream is lean (more oxygen), HO2S produces a low voltage signal. When exhaust stream is rich (less oxygen), HO2S produces a high voltage signal. The PCM monitors HO2S activity to determine a time ratio for lean-to-rich switches, and for rich-to-lean switches. The PCM counts number of lean-to-rich and rich-to-lean switches for 100 seconds. The PCM records time required to complete all transitions. With this information, PCM determines an average transition time for lean-to-rich switches and for rich-to-lean switches.
Powertrain Control Module (PCM) has the ability to disable 4 injectors during an engine over temperature (overheating) condition. Engine is considered over temperature whenever ECT reaches 268°F (131°C). This protection mode allows PCM to alternate between groups of cylinders, thereby reducing coolant temperature. This is accomplished by disabling the fuel injectors. DTC P1258 will set to show that an overheating condition was or is observed by the PCM and that the protection mode has been engaged.
Crankshaft Position (CKP) system variation learning feature is used to calculate the reference period errors that are caused by slight tolerance variations in crankshaft, and in CKP sensors. Calculated error allows the Powertrain Control Module (PCM) to accurately compensate for reference period variations. This procedure enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load conditions. PCM stores CKP system variation values after a learn procedure has been performed. DTC P1336 indicates CKP system variation values have not been stored in the PCM, and CKP system variation learn procedure must be performed. CKP system variation learn procedure must be performed any time the following service procedures are performed, regardless if DTC P1336 is set or not
- PCM replacement.
- PCM reprogrammed.
- Engine replacement.
- Crankshaft replacement.
- CKP sensor replacement.
- Any engine repairs which disturbs crankshaft to crankshaft position sensor relationship.
DTC will set if PCM has not successfully learned crankshaft position system variation.
Vehicle is equipped with 2 separate ignition module assemblies. One assembly for each bank of cylinders. Each assembly contains an Ignition Control Module (ICM) and 3 ignition coils. Each ICM consists of an ignition 1 voltage circuit, ground circuit, IC timing low reference circuit and IC control circuits for cylinders No. 1-6. Each ignition coil connects directly to its spark plug via a short boot. The IC circuits transmit timing pulses from the Powertrain Control Module (PCM) to the ICMs, which triggers the coils to fire the plugs in the correct sequence. The PCM monitors each IC circuit for improper voltage levels. DTC P1351-P1366 will set if PCM detects an incorrect voltage potential on the ignition control circuit.
Powertrain Control Module (PCM) uses dual Crankshaft Position (CKP "A" and CKP "B") sensors to determine crankshaft position. Both CKP sensors are located within one housing. PCM supplies an ignition voltage and a ground for each sensor. During engine rotation, a slotted ring, machined into the crankshaft, causes CKP sensors to return a series of on and off pulses to the PCM. The PCM uses these pulses to decode position of crankshaft. The PCM uses 2 basic methods of decoding engine position: angle based and time based (using either CKP "A" or CKP "B" sensor input). During normal operation, the PCM uses the angle based method. In order to operate in this mode, PCM must receive signal pulses from both CKP sensors. The PCM uses the signal pulses to determine an initial crankshaft position, and to generate 24X reference and 4X reference signals. Once initial crankshaft position is determined, the PCM continuously monitors both sensors for valid signal inputs. As long as both signal inputs remain, the PCM will continue to use the angle based mode. When either CKP signal is lost, the PCM will compare the 24X reference signal to the Camshaft Position (CMP) sensor signal. If PCM detects a valid CMP signal, and the 24X reference to CMP signal correlation is correct, the PCM determines that CKP sensor "A" is at fault. However, if the 24X reference to CMP correlation is incorrect, the PCM determines that CKP sensor "B" is at fault. If, while in angle-based mode PCM detects an intermittent loss of either CKP signal, DTC P1372.
Rough roads cause torque on the tires that is transmitted to the powertrain. This condition slows down the crankshaft, giving the appearance of a misfire. Electronic Brake and Traction Control Module (EBTCM) determines rough road surfaces using input from wheel speed sensors. EBTCM then sends rough road data to the Powertrain Control Module (PCM) via class 2 serial data. PCM uses rough road data to enhance misfire diagnostics. This data allows PCM to distinguish crankshaft speed variations causes by rough road surfaces from variations caused by true misfires. If EBTCM is unable to identify rough road conditions when PCM detects a misfire condition, DTC P1380 will set.
Rough roads cause torque on the tires that is transmitted to the powertrain. This condition slows down the crankshaft, giving the appearance of a misfire. Electronic Brake and Traction Control Module (EBTCM) determines rough road surfaces using input from wheel speed sensors. EBTCM then sends rough road data to the Powertrain Control Module (PCM) via class 2 serial data. PCM uses rough road data to enhance misfire diagnostics. This data allows PCM to distinguish crankshaft speed variations causes by rough road surfaces from variations caused by true misfires. If a loss of communication occurs that causes PCM not to receive rough road information when a misfire condition is requesting Malfunction Indicator Light (MIL) on, DTC P1381 will set.
The Powertrain Control Module (PCM) monitors Exhaust Gas Recirculation (EGR) valve pintle position input to ensure valve responds properly to PCM commands. When ignition is turned on, the PCM learns the EGR learned minimum position. PCM compares this position to EGR position sensor when EGR valve is commanded closed. If EGR position sensor indicates EGR valve is still open when PCM is commanding EGR valve closed, DTC P1404 will set.
This DTC tests for undesired intake manifold vacuum flow to Evaporative Emission (EVAP) system. The Powertrain Control Module (PCM) seals the EVAP system by commanding EVAP canister purge valve off and EVAP canister vent valve on. The PCM monitors Fuel Tank Pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, DTC P1441 will set.
Dash Integration Module (DIM) monitors the A/C low side refrigerant temperature via the A/C refrigerant low temperature sensor. When the refrigerant is cold, the sensor resistance and signal voltage are high. When the refrigerant is warm, the sensor resistance and signal voltage are low. The DIM will not request A/C compressor clutch engagement when the refrigerant temperature is low enough to cause the A/C evaporator core to freeze.
Engine Coolant Temperature (ECT) sensor is a thermistor. The Powertrain Control Module (PCM) determines the temperature of the engine coolant based on voltage from the ECT sensor. When ECT sensor is cold, resistance and voltage are high. When ECT sensor is warm, resistance and voltage are low. The PCM sends the coolant temperature data to the Dash Integration Module (DIM) over the Class 2 communication line. The DIM will not request A/C compressor clutch engagement if engine coolant temperature is too high. If PCM determines that a fault is present in the ECT sensor signal circuit it will set DTC P0117 or P0118 and substitute a default coolant temperature value. This value is then sent from the PCM to the DIM over the Class 2 communication line.
Powertrain Control Module (PCM) monitors the high side refrigerant pressure via the A/C refrigerant pressure sensor. The PCM applies a 5-volt reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the A/C refrigerant pressure input to the PCM to vary. When pressure is high, signal voltage is high. When pressure is low, signal voltage is low. When the pressure is high the PCM commands the cooling fans on. When the pressure is too high or low the PCM will not allow the A/C compressor clutch to engage. When the DTC P1540 is set, the PCM does not allow the A/C compressor clutch to engage. This is done to protect the compressor. The PCM sends the A/C pressure data to the Dash Integration Module (DIM) over the class 2 communication line. DTC will set if A/C pressure is too high.
This test functions on the assumption that a sudden decrease in non-drive wheel speed must be caused by a brake application. Non-drive wheel speed and brakelight switch status are supplied to the PCM through the serial data from the Electronic Brake and Traction Control Module (EBTCM). If there is a 6 MPH or greater decrease of non-drive wheel speed in .4 second and a transition of the Torque Converter Clutch (TCC) or extended travel contacts of the TCC brake switch occurs without a transition of the stoplight switch, DTC P1575 will set.
Powertrain Control Module (PCM) uses 5-volt reference "A" circuit as a sensor feed to the Throttle Position (TP) sensor, Manifold Absolute Pressure (MAP) sensor, Engine Oil Pressure (EOP) sensor and Exhaust Gas Recirculation (EGR) position sensor. The PCM monitors voltage on the 5-volt reference "A" circuit. If the voltage is out of tolerance, DTC P1635 will set.
Powertrain Control Module (PCM) uses the 5-volt reference "B" circuit as a sensor feed to the A/C pressure sensor and Fuel Tank Pressure (FTP) sensor. The PCM monitors voltage on the 5-volt reference "B" circuit. If the voltage is out of tolerance, DTC P1639 will set.
Output Driver Modules (ODM) are chips that are inside the Powertrain Control Module (PCM). ODMs provide grounded outputs that control devices. Each output has an internal feedback circuit that connects to the PCM microprocessor. ODM 1 determines if voltage or current may cause damage to the PCM. The PCM monitors voltage through ignition 1 input. Any incorrect current that is on a circuit to ODM will cause the ODM to report DTC P1640.
Output Driver Modules (ODM) are chips that are inside the Powertrain Control Module (PCM). ODMs provide grounded outputs that control devices. Each output has an internal feedback circuit that connects to the PCM microprocessor. ODM 2 determines if voltage or current may cause damage to the PCM. The PCM monitors voltage through battery input. Any incorrect current that is on a circuit to ODM, will cause the ODM to report DTC P1650.
Output Driver Modules (ODM) are chips that are inside the Powertrain Control Module (PCM). ODMs provide grounded outputs that control devices. Each output has an internal feedback circuit that connects to the PCM microprocessor. ODM 3 determines if voltage or current may cause damage to the PCM. The PCM monitors voltage through ignition 1 input. Any incorrect current that is on a circuit to ODM will cause the ODM to report DTC P1660.
Output Driver Modules (ODM) are chips that are inside the Powertrain Control Module (PCM). ODMs provide grounded outputs that control devices. Each output has an internal feedback circuit that connects to the PCM microprocessor. ODM 4 determines if voltage or current may cause damage to the PCM. The PCM monitors voltage through ignition 1 input. Any incorrect current that is on a circuit to ODM will cause the ODM to report DTC P1670.