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| Illustration 1 | g00635162 |
Typical example (1) Camshaft position sensor (2) Boost pressure sensor (3) Connector for the electronic unit injector P300/J300 (4) Inlet air temperature sensor (5) Ground point for the OEM (6) Engine Control Module (ECM) (7) Crankshaft position sensor (8) Fuel temperature sensor (9) Atmospheric pressure sensor (10) Engine oil pressure sensor (11) ECM connector that is for the engine (12) ECM connector that is for the OEM | |
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| Illustration 2 | g00635165 |
Typical example (13) Coolant temperature sensor | |
Engine Monitoring
Note: Refer to the Troubleshooting Guide for more information about the engine electronics.
The electronic control system includes Engine Monitoring. The system monitors engine oil pressure, coolant temperature, inlet manifold air temperature and coolant level. All truck engines are shipped from the factory with the following sensors: oil pressure sensor, coolant temperature sensor and inlet manifold air temperature. The OEM is responsible for providing and installing the coolant level sensor. The coolant level sensor is the only sensor that can be individually selected for Engine Monitoring. The ECM Customer Programmable Parameter enables the coolant level sensor. The default factory setting is "NO". The ECM Customer Programmable Parameters have four levels that are for Engine Monitoring:
- OFF
- Warning (Factory Default)
- Derate
- Shutdown
"Off Mode"
The ECM will ignore the oil pressure sensor and the coolant level sensor. Coolant Temperature is still used for Cold Mode. Inlet Manifold Air Temperature is used for operation in cold air regardless of the engine monitoring mode.
Warning Mode
Warning mode uses the following sensors: Oil Pressure, Coolant Temperature, Inlet Manifold Temperature and Optional Coolant Level Sensor. Table 1 indicates the diagnostic codes that are available. The table also shows the effect on engine performance when the diagnostic code is active. When a diagnostic code is active, the Check Engine Lamp will flash and the Warning Lamp will come on.
| PID-FMI | Description of the Fault Code | Warning Lamp | Derate |
| 100-01 | Low Oil Pressure Warning | SOLID | NONE |
| 100-11 | Very Low Oil Pressure Warning | SOLID | NONE |
| 105-00 | High Inlet Manifold Air Temperature | SOLID | NONE |
| 105-11 | Very High Inlet Manifold Air Temperature | SOLID | NONE |
| 110-00 | High Coolant Temperature Warning | SOLID | NONE |
| 110-11 | Very High Coolant Temperature | SOLID | NONE |
| 111-01 | Low Coolant Level Warning | SOLID | NONE |
| 111-11 | Very Low Coolant Level | SOLID | NONE |
"Derate" and "Shutdown" Modes
Derate mode and Shutdown mode allow the ECM to alter engine performance in order to avoid damage to the engine. The engine should return to normal conditions once the problem is corrected. When the engine is derated, the Check Engine Lamp and the Warning Lamp will flash. Refer to Table 2. In the Derate column, MPH indicates that the vehicle speed is derated. The maximum derate is 45 mph. HP indicates that the engine horsepower is limited. The maximum derate is 160 hp. RPM indicates that the engine speed is limited. The maximum derate is 1350 rpm. For the operating conditions that cause these codes, refer to the appropriate section for the sensor.
| PID-FMI | Description of the Fault Code | Warning Lamp | Derate |
| 100-01 | Low Oil Pressure Warning | SOLID | NONE |
| 100-11 | Very Low Oil Pressure Warning | FLASH | MPH, HP, RPM |
| 105-00 | High Inlet Manifold Air Temperature | SOLID | NONE |
| 105-11 | Very High Inlet Manifold Air Temperature | SOLID | NONE |
| 110-00 | High Coolant Temperature Warning | FLASH | MPH, HP |
| 110-11 | Very High Coolant Temperature | FLASH | MPH, HP |
| 111-01 | Low Coolant Level Warning | SOLID | NONE |
| 111-11 | Very Low Coolant Level | FLASH | MPH, HP |
Engine Monitoring Time to Shutdown
Table 3 indicates the active diagnostic codes that are capable of shutting down the engine when the ECM is programmed to Shutdown. The "Time To Shutdown" column indicates the amount of time of engine operation after a diagnostic code is activated. The engine must have been running for at least thirty seconds in order to activate this mode. The "Start/Restart Time" column indicates the amount of time for engine operation after start-up if the condition still exists. The "Start/Restart Time" follows a shutdown that is caused by the "Engine Monitoring" function. A "NO" indicates that the code will not cause a shutdown of the engine.
| PID-FMI | Description of the Fault Code | Time To Shutdown | Start and Restart Time |
| 100-01 | Low Oil Pressure Warning | NO | NO |
| 100-11 | Very Low Oil Pressure Warning | 30 sec | 18 sec |
| 105-00 | High Inlet Manifold Air Temperature | NO | NO |
| 105-11 | Very High Inlet Manifold Air Temperature | NO | NO |
| 110-00 | High Coolant Temperature Warning | NO | NO |
| 110-11 | Very High Coolant Temperature | 20 sec | 60 sec |
| 111-01 | Low Coolant Level Warning | NO | NO |
| 111-11 | Very Low Coolant Level | 30 sec | 80 sec |
Flash Codes and Diagnostic Codes
| Flash Code | Code | Description of Code | Reference |
|---|---|---|---|
| 00 |
0052-11 | Air Inlet Shutoff Shutdown | Troubleshooting, "Air Inlet Shutoff Circuit - Test" |
| 00 |
0084-14 | Quick Stop Occurrence | Troubleshooting, "Event Codes - Test" |
| 00 |
0166-11 | Rated Engine Power Derate | |
| 00 |
0171-03 | Outside Air Temp Sensor Open Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 00 |
0171-04 | Outside Air Temp Sensor Short Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 00 |
0171-11 | No Ambient Air Temperature Data | Troubleshooting, "Idle Shutdown Timer and PTO Shutdown Timer - Test" |
| 00 |
0224-11 | Theft Deterrent Active | Troubleshooting, "Event Codes - Test" |
| 00 |
0224-14 | Engine Cranking with Theft Deterrent Active | Troubleshooting, "Event Codes - Test" |
| 00 |
0246-11 | Brake Switch # 1 | Troubleshooting, "Cruise Control Circuit, Service Brake Pedal Position Switch No. 1 Circuit, and Clutch Pedal Position Switch Circuit - Test" |
| 00 |
0247-11 | Brake Switch # 2 | Troubleshooting, "PTO Switch Circuit - Test" |
| 01 |
0071-00 | Idle Shutdown Override | Troubleshooting, "Idle Shutdown Timer and PTO Shutdown Timer - Test" |
| 12 |
0111-02 | Coolant Level Sensor Fault | Troubleshooting, "Coolant Level Sensor Circuit - Test" |
| 12 |
0111-03 | Coolant Level Sensor Open Circuit | Troubleshooting, "Coolant Level Sensor Circuit - Test" |
| 12 |
0111-04 | Coolant Level Sensor Short Circuit | Troubleshooting, "Coolant Level Sensor Circuit - Test" |
| 13 |
0174-03 | Fuel Temperature Sensor Open Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 13 |
0174-04 | Fuel Temperature Sensor Short Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 14 |
0121-05 | Retarder Solenoid Low/High Open Circuit | Troubleshooting, "Retarder (Compression Brake) Solenoid Circuit - Test" |
| 14 |
0121-06 | Retarder Solenoid Low/High Short Circuit | Troubleshooting, "Retarder (Compression Brake) Solenoid Circuit - Test" |
| 14 |
0122-05 | Retarder Solenoid Med/High Open Circuit | Troubleshooting, "Retarder (Compression Brake) Solenoid Circuit - Test" |
| 14 |
0122-06 | Retarder Solenoid Med/High Short Circuit | Troubleshooting, "Retarder (Compression Brake) Solenoid Circuit - Test" |
| 16 |
0173-00 | High Exhaust Gas Temperature Derate | Troubleshooting, "Wastegate Solenoid - Test" |
| 16 |
0173-11 | High Exhaust Gas Temperature Derate | Troubleshooting, "Wastegate Solenoid - Test" |
| 21 |
0041-03 | 8 Volt Supply Above Normal | Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - Test" Troubleshooting, "Remote PTO Accelerator Position Sensor Circuit - Test" |
| 21 |
0041-04 | 8 Volt Supply Below Normal | Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - Test" Troubleshooting, "Remote PTO Accelerator Position Sensor Circuit - Test" |
| 21 |
0232-03 | 5 Volt Supply Above Normal | Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test" |
| 21 |
0232-04 | 5 Volt Supply Below Normal | Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test" |
| 24 |
0100-03 | Oil Pressure Sensor Open Circuit | Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test" |
| 24 |
0100-04 | Oil Pressure Sensor Short Circuit | Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test" |
| 25 |
0102-00 | Boost Pressure Reading Stuck High | Troubleshooting, "Wastegate Solenoid - Test" |
| 25 |
0102-01 | Boost Pressure Reading Stuck Low | Troubleshooting, "Wastegate Solenoid - Test" |
| 25 |
0102-02 | Erratic Boost Pressure | Troubleshooting, "Wastegate Solenoid - Test" |
| 25 |
0102-03 | Boost Pressure Sensor Open Circuit | Troubleshooting, "Wastegate Solenoid - Test" |
| 25 |
0102-04 | Boost Pressure Sensor Short Circuit | Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test" |
| 25 |
0102-07 | Excessive Boost Pressure | Troubleshooting, "Wastegate Solenoid - Test" |
| 26 |
0108-03 | Atmospheric Pr Sensor Open Circuit | Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test" |
| 26 |
0108-04 | Atmospheric Pr Sensor Short Circuit | Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test" |
| 27 |
0110-03 | Coolant Temp Sensor Open Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 27 |
0110-04 | Coolant Temp Sensor Short Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 28 |
0091-13 | Throttle Sensor Calibration | Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - Test" |
| 29 |
0030-08 | Invalid PTO Throttle Signal | Troubleshooting, "Remote PTO Accelerator Position Sensor Circuit - Test" |
| 29 |
0030-13 | PTO Throttle Sensor Calibration | Troubleshooting, "Remote PTO Accelerator Position Sensor Circuit - Test" |
| 31 |
0084-01 | Loss of Vehicle Speed Signal | Troubleshooting, "Vehicle Speed Circuit - Test" |
| 32 |
0091-08 | Invalid Throttle Signal | Troubleshooting, "Accelerator Pedal (Throttle) Position Sensor Circuit - Test" |
| 33 |
0032-03 | Turbo Wastegate Solenoid Output Open Circuit | Troubleshooting, "Wastegate Solenoid - Test" |
| 33 |
0032-04 | Turbo Wastegate Solenoid Output Short Circuit | Troubleshooting, "Wastegate Solenoid - Test" |
| 33 |
0032-06 | Turbo Wastegate Solenoid Short to +Batt | Troubleshooting, "Wastegate Solenoid - Test" |
| 34 |
0064-12 | Loss of Engine Cam Sensor RPM Signal | Troubleshooting, "Engine Speed/Timing Circuit - Test" |
| 34 |
0190-12 | Loss of Engine Crank Sensor RPM Signal | Troubleshooting, "Engine Speed/Timing Circuit - Test" |
| 35 |
0190-00 | Engine Overspeed Warning | Troubleshooting, "Event Codes - Test" |
| 36 |
0084-02 | Invalid Vehicle Speed Signal | Troubleshooting, "Vehicle Speed Circuit - Test" |
| 36 |
0084-08 | Vehicle Speed Out of Range | Troubleshooting, "Vehicle Speed Circuit - Test" |
| 36 |
0084-10 | Vehicle Speed Rate of Change | Troubleshooting, "Vehicle Speed Circuit - Test" |
| 38 |
0105-03 | Inlet Manifold Temp Sensor Open Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 38 |
0105-04 | Inlet Manifold Temp Sensor Short Circuit | Troubleshooting, "Engine Temperature Sensor Open or Short Circuit - Test" |
| 41 |
0084-00 | Vehicle Overspeed Warning | Troubleshooting, "Event Codes - Test" |
| 42 |
0022-11 | Camshaft Sensor to Crank Sensor Calibration | Troubleshooting, "Engine Speed/Timing Circuit - Test" |
| 42 |
0022-13 | Check Timing Sensor Calibration | Troubleshooting, "Engine Speed/Timing Sensor - Calibrate" |
| 46 |
0100-01 | Low Oil Pressure Warning | Troubleshooting, "Event Codes - Test" |
| 46 |
0100-11 | Very Low Oil Pressure | Troubleshooting, "Event Codes - Test" |
| 47 |
0071-01 | Idle Shutdown Occurrence | Troubleshooting, " PTO Shutdown Timer - Test" |
| 47 |
0071-14 | PTO Shutdown Timer Occurrence | Troubleshooting, "Idle Shutdown Timer and PTO Shutdown Timer - Test" |
| 51 |
0168-02 | Intermittent Battery | Troubleshooting, "Ignition Key Switch Circuit and Battery Supply Circuit - Test" |
| 55 |
N/A | No Diagnostic Code Detected | Troubleshooting, "Event Codes - Test" |
| 56 |
0253-02 | Check Customer or System Parameters | Troubleshooting, "ECM Memory - Test" |
| 56 |
0253-11 | Check Transmission Customer Parameters | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 58 |
0231-02 | J1939 Required Data Not Received | Troubleshooting, "Powertrain Data Link Circuit - Test" |
| 58 |
0231-12 | J1939 Device Not Responding | Troubleshooting, "Powertrain Data Link Circuit - Test" |
| 58 |
0249-11 | J1922 Data Link Fault | Troubleshooting, "Powertrain Data Link Circuit - Test" |
| 59 |
0252-11 | Incorrect Engine Software | Troubleshooting, "ECM Memory - Test" |
| 61 |
0110-00 | High Coolant Temperature Warning | Troubleshooting, "Event Codes - Test" |
| 61 |
0110-11 | Very High Coolant Temperature | Troubleshooting, "Event Codes - Test" |
| 62 |
0111-01 | Low Coolant Level Warning | Troubleshooting, "Event Codes - Test" |
| 62 |
0111-11 | Very Low Coolant Level | Troubleshooting, "Event Codes - Test" |
| 62 |
0111-14 | Early Hour Low Coolant Level | Troubleshooting, "Event Codes - Test" |
| 64 |
0105-00 | High Inlet Manifold Temp Warning | Troubleshooting, "Event Codes - Test" |
| 64 |
0105-11 | Very High Inlet Manifold Temp | Troubleshooting, "Event Codes - Test" |
| 65 |
0174-00 | High Fuel Temperature Warning | Troubleshooting, "Event Codes - Test" |
| 66 |
0054-05 | Output # 6 Open Circuit | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 66 |
0054-06 | Output # 6 Short Circuit | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 67 |
0055-05 | Output # 7 Open Circuit | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 67 |
0055-06 | Output # 7 Short Circuit | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 68 |
0191-07 | Transmission Not Responding | Troubleshooting, "Eaton Top 2 Transmission Circuit - Test" |
| 71 |
0043-02 | Ignition Key Switch Fault | Troubleshooting, "Ignition Key Switch Circuit and Battery Supply Circuit - Test" |
| 72 |
0001-11 | Cylinder 1 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
| 72 |
0002-11 | Cylinder 2 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
| 73 |
0003-11 | Cylinder 3 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
| 73 |
0004-11 | Cylinder 4 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
| 74 |
0005-11 | Cylinder 5 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
| 74 |
0006-11 | Cylinder 6 Fault | Troubleshooting, "Injector Solenoid Circuit - Test" |
Electronic Control System Operation
The fuel delivery and injection timing are electronically controlled. In comparison to engines that are controlled mechanically, the electronic control system provides increased control of timing and increased control to the air to fuel ratio. Injection timing is achieved by precise control of injector firing time, and engine power is controlled by adjusting the firing duration. The ECM energizes the fuel injection solenoid in order to start the injection of fuel. The ECM will de-energize the fuel injection solenoid in order to stop the injection of fuel. Refer to the Systems Operation, "Fuel System" for a complete explanation of the fuel injection process.
The engine uses the following types of electronic components: input, control and output.
An input component is one that sends an electrical signal to the ECM. The signal that is sent varies in either voltage or in frequency when there is a change in some specific system of the vehicle. An example would be the engine speed/timing sensor or the coolant temperature sensor. The electronic control module sees the input sensor signal as information about the condition, environment, or operation of the vehicle.
An electronic control system component receives the input signals. Electronic circuits that are inside the ECM evaluate the signals. The ECM then supplies electrical energy to the output components of the system, which are in response to predetermined combinations of input signal values.
An output component is one that is operated by the ECM. An output component receives electrical energy from the ECM. The electrical energy is used to perform one of the following functions:
- Perform work. An example would be moving a solenoid plunger. An output component takes an active part in regulating or operating the vehicle.
- An output component can give information or a warning. An example would be a light or an alarm to the operator of the vehicle or other person.
Output components provide the ability to electronically control the engine operation in order to improve the following items: performance, fuel consumption rate and reduced emissions levels. A brief description of the sensors that are used in the electronic control system follows:
Atmospheric Pressure Sensor
The atmospheric pressure sensor is an absolute pressure sensor that measures crankcase pressure. Both the boost pressure and the oil pressure are communicated to the service tools and over the data link. The two pressures are calculated by subtracting the reading for the atmospheric pressure sensor. The atmospheric pressure sensor measures pressure from 0 (0) to 116 kPa (17 psi). The atmospheric pressure sensor is supplied with + 5 VDC by the ECM.
Boost Pressure Sensor
The boost pressure sensor is an absolute pressure sensor that measures inlet manifold pressure. The difference between the inlet manifold pressure measurement and the pressure that is measured by the atmospheric pressure sensor is called the boost pressure. The information is communicated to the service tools and over the data link. The boost pressure sensor measures pressure from 20 kPa (3 psi) to 472 kPa (68 psi). The boost pressure sensor is supplied with + 5 VDC by the ECM.
Coolant Level Sensor
The coolant level sensor is installed by the vehicle OEM. The coolant level sensor is an optional sensor. The coolant level sensor is selected through the ECM Customer Programmable Parameter. The ECM Customer Programmable Parameters can be protected by Customer Passwords.
Coolant Temperature Sensor
The engine coolant temperature is measured by an electronic sensor that is mounted on the water temperature regulator housing. The coolant temperature signal is used to adjust the engine fueling and the engine timing for improved cold start and white smoke reduction. The ECM supplies the coolant temperature sensor with 5.0 ± .5 VDC. The sensor output voltage is + 0.5 to + 4.5 VDC. The sensor output voltage depends on the engine coolant temperature. Coolant temperature is used to indicate the Cold Mode operation and coolant temperature is used for Engine Monitoring.
Coolant Temperature Engine Monitoring Operation
The Check Engine Lamp will flash if Engine Monitoring is programmed to derate the engine. The Check Engine Lamp will flash if Engine Monitoring is programmed to shut down the engine. The Warning Lamp will then flash when the associated diagnostic code is active. When the Warning Lamp flashes, the engine is in Derate Mode.
Fuel Temperature Sensor
The fuel temperature is monitored in order to adjust the fuel rate. The temperature of the fuel is also monitored in order to correct the power output of the engine. The power of the engine is adjusted in order to provide constant power when fuel temperatures exceed 30°C (86°F). The maximum correction of the power occurs when the fuel temperature reaches 70°C (158°F). Fuel temperature that exceeds 90°C (194°F) for ten minutes causes a diagnostic code to be logged.
Inlet Manifold Temperature Sensor
Inlet manifold temperature is used for the cooling fan driver and Engine Monitoring. The inlet manifold temperature sensor is used in order to warn the driver of an excessive inlet manifold air temperature. When Engine Monitoring has been programmed to derate the engine, the inlet manifold temperature sensor will not cause the following events: derate and shutdown.
Before a diagnostic code is logged into the ECM, the inlet manifold air temperature must exceed the temperatures that are indicated for thirty seconds. A diagnostic code for the High Inlet Manifold Temperature is triggered at 91°C (195°F). A diagnostic code for the Very High Inlet Manifold Temperature is triggered at 110°C (230°F). Unlike the diagnostic codes that are associated with Engine Monitoring, the codes that are associated with the inlet manifold air temperature are still available when Engine Monitoring is "OFF". The Warning Lamp is also turned on if Engine Monitoring is programmed to Warning, Derate, or Shutdown.
Oil Pressure Sensor
The oil pressure sensor is an absolute pressure sensor that measures oil pressure in the oil gallery. The oil pressure is communicated over the data link and the oil pressure is displayed by the electronic service tool. The ECM uses the sensor input only if the parameter for Engine Monitoring is programmed to Warning, Derate, or Shutdown. The oil pressure sensor measures pressure from 0 kPa (0 psi) to 1135 kPa (165 psi). The sensor is supplied by the ECM with 5 VDC.
Retarder Enable for the Compression Brake
If the engine is equipped with a compression brake, the operation of the compression brake is provided through the RETARDER enable output. The RETARDER enable status is determined by the ECM. In order to determine the RETARDER enable status, the following items are monitored by the ECM: dash switch for the compression brake, clutch switch, accelerator pedal position, cruise control switch and engine speed (rpm). Operation of the compression brake will be restricted under improper engine operating conditions. The following conditions must be met in order to enable the compression brake:
- The engine speed (rpm) is above 1000 rpm.
- The accelerator pedal not pressed.
- The clutch pedal is not depressed.
- The cruise control switch is "OFF".
- The switch for the compression brake is energized.
Camshaft Position Sensor and Crankshaft Position Sensor
The camshaft position sensor and the crankshaft position sensor are used to determine both engine speed and fuel injection timing. The camshaft position sensor senses motion of the camshaft. The crankshaft position sensor senses motion of the crankshaft.
Accelerator Pedal Position Sensor
The accelerator pedal position sensor is an electronic sensor that is connected to the accelerator pedal. The accelerator pedal position sensor sends a Pulse Width Modulated Signal to the ECM.
Vehicle Speed Sensor
The vehicle speed sensor is an electromagnetic pickup that measures vehicle speed. The sensor measures vehicle speed from the rotation of the gear teeth that are in the drive train of the vehicle.
Check Engine Lamp (Diagnostic Lamp)
The Check Engine Lamp is sometimes referred to as the Diagnostic Lamp. The Check Engine Lamp is located on the dashboard of the vehicle. The Check Engine Lamp can be used as a diagnostic lamp in order to communicate any problems with the operation of the electronic control system.
Note: The Check Engine Lamp and the Warning Lamp are different. For more information about terminology for electronic components, refer to Systems Operation, "Glossary of Electronic Control Terms".
When a diagnostic fault is detected by the ECM, the Check Engine Lamp will turn ON. When a diagnostic fault is detected by the ECM, the Check Engine Lamp will blink at five second intervals. The Check Engine Lamp should be ON and the Check Engine Lamp should be flashing Diagnostic Code 55 whenever the START switch is turned ON but the engine is not running. This condition will test whether the lamp is operating correctly.
If the Check Engine Lamp comes ON and the Check Engine Lamp stays ON after the initial start-up, the system has detected a fault. The Check Engine Lamp or service tools can be used to identify the diagnostic code.
The dash mounted Cruise Control Switches are used to interrogate the ECM for system status. With the Cruise Control Switch in the OFF position, move the SET/RESUME switch to the RESUME position. The Check Engine Lamp will begin to flash in order to indicate a two digit diagnostic code while the SET/RESUME switch is held in the RESUME position. The sequence of flashes represents the system diagnostic message. The first sequence of flashes adds up to the first digit of the diagnostic code. After a one second pause, a second sequence of flashes will occur. The second sequence of flashes represent the second digit of the diagnostic code. If necessary, additional diagnostic codes will follow after a three second pause. Additional diagnostic codes will be displayed in the same manner.
The Check Engine Lamp is also used to monitor the Idle Shutdown Timer. The Check Engine Lamp will start to flash at a rapid rate 90 seconds before the programmed idle time is reached. If the clutch pedal indicates a change in position or the service brake pedal indicates a change in position during the final 90 seconds, the idle shutdown timer will be disabled. The idle shutdown timer will then need to be reset.
Engine Control Module
The ECM power supply provides electrical power to all engine mounted sensors and actuators. Reverse voltage polarity protection and resistance to vehicle power system voltage swings or surges have been designed into the ECM. The ECM also monitors all input from the sensors. The ECM also provides the correct outputs in order to ensure desired engine operation.
The ECM contains memory in order to store customer specified parameters. The ECM also identifies a selected factory engine rating. The memory also contains a personality module identification code in order to prevent unauthorized tampering. The memory also contains an identification code in order to prevent switching of engine ratings and other pertinent manufacturing information.
The wiring harness provides communication or signal paths to the various sensors. A boost pressure sensor, the Data Link Connector, and the engine/vehicle connectors are examples. The ECM performs many functions. The ECM contains all of the engine performance information. The ECM contains all of the information for the emission certification. Several examples are listed: engine timing, air/fuel ratio and rated fuel position control maps.
Note: The list that follows contains a portion of the customer specified parameters: Engine Power Rating, Vehicle Identification Number, "PTO Vehicle Speed Limit", PTO Engine RPM Limit (PTO RPM), Low Gear Limit, Intermediate Gear Limit, Engine RPM At Vehicle Speed Limit (ENG RPM At VSL), Geardown Protection, Top Engine Limit (TEL), Vehicle Speed Limit (VSL), High Gear Turn On Speed, Low Cruise Control Set Limit (LCC), High Cruise Control Set Limit, Retarder Coast/Latch and Idle Shutdown Timer. The customer specified parameters may be secured by customer passwords. An ECM may have all of the programmed parameters or any combination of the programmed parameters. For a brief explanation of each of the customer specified parameters, refer to the Troubleshooting Guide.
The ECM is programmed to run diagnostic tests in order to separate a fault to a specific circuit. Once a fault is detected, the fault can be displayed in several ways on the dash mounted Check Engine Lamp. Several examples of the displays are listed: flashing coded display (representing a diagnostic fault code) on the dash mounted Check Engine Lamp and diagnostic codes can be read by the use of an electronic service tool. The ECM will log most of the diagnostic codes that are generated during engine operation. The logged codes or the active codes can be read by an electronic service tool.
Cooling Fan Relay Driver
The ECM provides a cooling fan disable signal. If the ECM output is high, the fan is off. The cooling fan disable signal is for "ON/OFF" control of the cooling system fan. The "ON/OFF" control is based on the following items: coolant temperature, engine brake operation, engine speed and inlet manifold air temperature. The "ON/OFF" control is also based on the OEM installed air conditioning high pressure switch. All other control of the cooling fan is the responsibility of the OEM.
In order to prevent unnecessary cycling of the cooling fan due to reduced voltage levels during engine cranking, the ECM turns the fan "OFF". Because an electrical open circuit is the most likely failure mode, Caterpillar recommends a normally open relay for this circuit.