California Career and Technical Education Standards

• T.C.C1.2 Practice the safe handling and storage of chemicals and hazardous wastes in acco...
• T.C.C1.3 Understand the way in which waste gasses, emissions, and other environmentally d...
• T.C.C1.5 Use appropriate personal protective equipment and safety practices.
• T.C.C7.7 Perform necessary procedures to maintain, diagnose, service and repair vehicle e...

California Academic Content Standards (Reinforced)

• ELA.9-10.R.CAGT.2.5 Extend ideas presented in primary or secondary sources through original analysis...3
• ELA.9-10.R.CAGT.2.6 Demonstrate use of sophisticated learning tools by following technical direction...2

• Live Engine - Hooks / Set

  Show students the following animation of an engine systems operation.

  • engine Movie.wmv [ Watch Video ] [ Download Original Video ]
• ECM or PCM - Lecture

  Have students follow along using the textbook ( Thomson Delmar Learning, "Automotive Technology: A Systems Approach," 4th edition ), pages 838-840.

  Start by explaining the ECM (Electronic Control Module) or  PCM (Power Control Module). The computer is where all the strategies for the engine control systems are made; it is the center of operations. For example:

  • Air /Fuel ratios are held as closely to 14.7 parts of air to 1 part of fuel, for maximum efficiency
  • Emission control devices, such as EGR valve, carbon cannister, and air pump, are operated at predetermined times to increase efficiency
  • The engine is operated as efficiently as possible when cold, so the engine is warmed up as fast as possible to minimize emissions
  • Ignition timing is advanced as much as possible under all conditions
  • Timing and air/fuel ratios are precisely controlled under all operating conditions
  • Control loop operation enables the engine to make rapid changes to match changes in engine temperature, load, and speed

  The ECM/PCM can do this because it has inputs sensors and output sensors to do the work.

  The location of the computer is different for each manufacture, you need to look up its location. See fig. 33-3.

  • ECM-PCM 006.jpg [ View Image ] [ Download Original ] Fig. 33-3
• The Major Primary Input Sensors - Lecture

  Have students follow along using the textbook ( Thomson Delmar Learning, "Automotive Technology: A Systems Approach," 4th edition ), pages 830-837.

  Start by explaining that there are 10 primery input sensors, and they are:

  Engine coolant Temperature (ECT) Sensor: This sensor inputs to the pcm at what temperature the engine is at, by reading the temperature of the coolant, and you can find this sensor around the thermostat housing. See fig.  33-4.                                                                     

  Barometric  Pressure (BARO) and Manifold Absolute Pressure (MAP) Sensors: This sensor monitors engine vacuum for the ECM/PCM to adjust air/fuel mixture and timing at different altitudes and engine load conditions, and you can find this sensor on the intake manifold or around the engine with a vacuum hose going to it from the intake manifold. See fig. 33-8.

  Engine Position Sensors: This sensor inputs to the computer the speed of the engine and when the piston in each cylinder is at Top Dead center (TDC).   The input is critical for adjusting the timing and the fuel injection delivery. and you can find this sensor in front of the engine near the crankshaft pully. See fig. 33-5.

  Engine Speed Sensor: Similar to the engine position sensor, the information from this sensor may be used by the ecm/pcm computer for determining Ignition timing (Advance), fuel delivery, emission control, torque converter clutch operation, and engine idle speed. You can find this sensor anywhere close to the crankshaft. See fig. 33-5.

  Intake Air Temperature (IAT) Sensor: This sensor is a thermistor. Its resistance decreases as intake air temperature increases and increases when the intake air temperature decreases. The ecm/pcm uses this input to help calculate fuel delivery. Cold air is denser; therefore, a richer air/fuel mixture is required, and warmer air leaner air/fuel mixture. You can find this sensor on the intake air duct before the Mass Air Flow Sensor (MAF). See fig. 33-6.

  Knock Sensor (KS): The knock sensor sends a signal to the ecm/pcm if a detonation is occurring in the cylinders. In turn, the computer retards the timing to avoid the knock. You can find this sensor on the engine block near the middle cylinders. See fig. 33-7.

  Mass Air Flow (MAF) Sensor: This sensor measures the flow of air entering the engine. This measurement of airflow is a reflection of engine load (throttle opening and air volume), This measurement of  air entering the engine determines the 14.7 parts of air to 1 part of fuel ratio. There are three types of (MAF) sensors:  the vane-type, heated resister-type, and the hot wire -type. You can find this sensor on the intake air duct after the intake Air Temperature (IAT) Sensor  and before the throttle plate. See fig. 33-6.

  Oxygen Sensor (O2S):   The oxygen sensor, or lambda sensor, as it is referred to on many import vehicles, is the key sensor in calculating and maintaining a balanced air/fuel mixture under all load conditions. There is one (O2S) or as much as six (O2S) found on the latest vehicles, there are two types and they are, single wire (O2S) and four wire (HOS). You can find this sensor on the exhaust manifold, exhaust pipe, and before and after the catalytic converter. See fig. 33-9.

  Throttle Position Sensor (TPS): All engines with electronic fuel injection and engines with carburator feed back systems use a (TPS) to inform the ecm/pcm of how fast the throttle is opening and at what position it's at.  For example, closed or idle, cruise speed, or wide open throttle.  It cross references this information with other sensors to verify the drivers intentions. You can find this sensor on the throttle body opposite of the throttle cam. See fig. 33-10.

  Vehicle Speed Sensor (VSS) : This sensor informs the ECM/PCM the vehicle's speed in miles per hour. This input controls when the torque converter clutch in the transmission locks up and also is used to control the cruise control, EGR flow, and canister purge (EVAP). You can find this sensor on the transmission close to the output shaft. See fig. 33-11.

  • ECM-PCM 001.jpg [ View Image ] [ Download Original ] Throttle Position Sensor Fig. 33-10
  • ECM-PCM 002.jpg [ View Image ] [ Download Original ] Coolant Temperature Sensor Fig. 33-4
  • ECM-PCM 003.jpg [ View Image ] [ Download Original ] Knock Sansor Fig. 33-7
  • ECM-PCM 004.jpg [ View Image ] [ Download Original ] ECM/PCM Computer
  • ECM-PCM 005.jpg [ View Image ] [ Download Original ] O2 Sensor Fig. 33-9
  • ECM/PCM 006.jpg [ View Image ] [ Download Original ] O2 Sensor Fig. 33-9
  • ECM/PCM 007.jpg [ View Image ] [ Download Original ] Vehicle Speed Sensor Fig. 33-11
  • ECM/PCM 008.jpg [ View Image ] [ Download Original ] Engine Speed and Position sensor Fig. 33-5
  • ECM/PCM 009.jpg [ View Image ] [ Download Original ] Manifold Absolute Sensor Fig. 33-8
  • ECM/PCM 0010.jpg [ View Image ] [ Download Original ] Manifold Absolute Sensor Fig. 33-8
• The Major Outputs and Actuators - Lecture

  Have students follow along using the textbook ( Thomson Delmar Learning, "Automotive Technology: A Systems Approach," 4th edition ), pages 838-840.

  Start by explaining that once the ECM/PCM has determined what adjustment or action needs to be made in any of the engine controlled systems, for example, Fuel delivery, Air injection, Evaporation Control, EGR Flow, Idle Speed, and Ignition Timing. Then the ECM/PCM computer commands actions as needed:

  Fuel Injectors: These electronic solenoids valves deliver the correct fuel amount to the intake port, in an atomized spray, for the engine conditions at that precise time. You can find the fuel injectors on the intake manifold before the cylinder head. See fig. 34-1.

  Idle Air Control (IAC) Idle Speed: These Actuators are small electric motors, that open the throttle on (Carburated) or open an air passage on (Fuel Injection) to increase idle speed. You can find the (IAC) on or close to the throttle body. See Fig. 34-2.

  Ignition module: This module is a small electronic on and off switching device that is triggered by a signal from the ECM/PCM, to adjust the timing and spark duration according to engine conditions. The ignition module may be a seperate unit or may  be part of the ECM/PCM computer. You can find the ignition module on a distributor, DIS coil pack, or as part of the ECM/PCM. See Fig. 34-3.

  EGR Flow Solenoids: The EGR flow on early vehicles is controlled by an electronic vacuum valve solenoid. This solenoid valve supplies manifold vacuum to the EGR valve when EGR is required or vent vacuum when EGR is not required. You can find this solenoid close to the EGR valve. On late vehicles the EGR valve its self is an electronic actuator (electric steper motor). See figures 34-4 and 34-5.

  Evaporative Emission (EVAP) Canister Purge Valve: This Valve is controlled by a purge solenoid. The valve controls when stored fuel vapors in the charcoal canister are drawn into the engine and burned. The ECM/PCM computer only activates this purge solenoid to open the valve when the engine is warm and above idle speed. You can find this purge solenoid in most cases close to the charcoal canister. See figures 34-6.

  Air Management Solenoids (AIS) : Secondary air Bypass and diverter solenoids control the flow of air from the air injection pump (AIR) to either the exhaust manifold when cold (open loop) or the catalytic converter when warm (close loop). You can find this solenoids close to the air injection pump. See fig. 34-7.

  • ECM-PCM outputs 001.jpg [ View Image ] [ Download Original ] Fuel Injectors Fig. 34-1
  • ECM-PCM outputs 002.jpg [ View Image ] [ Download Original ] Idle Air Control Fig. 34-2
  • ECM-PCM outputs 003.jpg [ View Image ] [ Download Original ] EGR Actuator Fig. 34-5
  • ECM-PCM outputs 004.jpg [ View Image ] [ Download Original ] Ignition Modules Fig. 34-3
  • ECM-PCM outputs 005.jpg [ View Image ] [ Download Original ] EGR Solenoid Fig. 34-4
  • ECM-PCM outputs 006.jpg [ View Image ] [ Download Original ] Canister Purge Valve Fig. 34-6
  • ECM-PCM outputs 006.jpg [ View Image ] [ Download Original ] Air Management Solenoid Fig. 34-7
• Input and Output Sensors Identification - Group Work

  Break the class into groups of two, and give them the list of parts covered in the lectures.  Have them go out to different vehicles and identify each part and location.

  Make your list for the vehicles you have in the shop.
• Clean up - Closure

  Have all studants pick up and sweep up if needed, wipe down vehicles worked on, put away any tools used and put away books.