The electronic diesel engine management system makes it possible to reduce fuel consumption and emissions of toxic components in the exhaust gas, to improve the quality of regulation (accuracy, smoothness and speed) and the stability of idle speed, and to reduce the harshness of the diesel engine's working process.
The electronic diesel engine management system consists of sensors and switches, an electronic control unit and actuators that act directly on the engine systems.
The equipment of the engine management system with sensors and actuators depends on the emission standard to which the engine corresponds (for example, Euro 3 or Euro 4), the vehicle's specification and the vehicle's purpose.
Information about the engine's operating mode and condition is supplied to the management system by the sensors, which convert the monitored (measured) engine parameters into electrical signals suitable for processing and transmission in the electronic management system.
The sensor signals are supplied to the electronic control unit, which, having processed the received information according to specified algorithms, issues control signals to the actuators on the basis of the driver's requests and the stored programme.
The control algorithms implemented by the microprocessor of the electronic control unit produce, at each engine operating mode, the optimal (best) combination — in terms of fuel consumption and emission standards — of fuel injection parameters (cyclic delivery and injection advance angle) and air charge parameters (boost pressure and exhaust gas recirculation rate).
The electronic control unit performs operations such as control of the cyclic fuel delivery, the fuel pressure in the accumulator, the injection advance angle, the idle speed, the cruise control function and the elements of the exhaust emission reduction subsystems.
To simplify fault-finding, a self-diagnosis function is built into the electronic control unit; it monitors numerous operating parameters of both the engine itself and all elements of the management system and, when a fault is determined, informs the driver by illuminating fault indicators on the instrument panel.
Self-diagnosis system
To enable the diagnostic mode, the ignition key must be set to position “I” and the check switch must be turned on.
In this mode the red and yellow indicators illuminate; in the absence of faults they remain inactive. If an active fault is present, the red indicator begins to flash.
The diagnostic system monitors four engine parameters: coolant level, coolant temperature, oil pressure and intake manifold air temperature, and derates the engine if one or more of the said parameters goes outside the permissible range.
The engine protection system may apply the derating function to the torque, the engine speed and a possible engine shutdown in a progressive order.
The ECU stores in memory data on the time of occurrence of events, the operating duration and the extreme values of pressure and temperature when it detects abnormal operating conditions.
Detailed information on the data list is displayed by means of programming tools.
The diagnostic check switch is intended to turn the diagnostic mode carried out on board the bus on and off. When the diagnostic mode is turned on, the stop lamp (STOP) and the warning lamp (engine) will display all active fault codes.
The diagnostic and idle increment increase/decrease switch at low speed is a dual-function, two-position switch without a detent; after the diagnostic mode is turned on, it allows movement through the fault code list. This switch is also used when adjusting the idle speed at low speed. The default step length is 25 rpm in the mode of positive and negative increments to the idle speed at low speed.
Four indicator lamps are used in the system: the stop lamp, the warning lamp, the service lamp and the start-wait lamp.
When the key switch is set to position “1” (“switching on the electrical equipment instruments”), the indicator lamps illuminate and, after approximately two seconds, go out one after another — in this way it is confirmed that the lamps are in working order and are connected correctly.
In the event of high coolant temperature, high intake manifold air temperature, low oil pressure or low coolant level, the indicator illuminates and, after some time, begins to flash. This flashing mode warns that the condition that has arisen has persisted for some time and that the subsequent pressure or temperature condition has deteriorated and the engine is close to a shutdown condition (the ECU may shut down the engine).
The warning indicator (engine) warns of a detected fault and signals the start of code display during on-board diagnostics. Illumination of the lamp reports an engine fault, while the vehicle remains operational (the situation is not an emergency). The vehicle must be serviced to eliminate the fault.
The stop indicator (STOP) signals a fault in one of the main systems. During on-board diagnostics, flashing of this lamp corresponds to the fault codes identified by the ECU. Illumination of the lamp warns of a serious fault. In this case the bus engine must be switched off as soon as possible, as far as safety requirements permit.
The service indicator (KEY) serves to notify the need for servicing and to warn the driver that the condition of the fluids in the engine is outside the permissible limits.
The start-wait indicator (START) warns the driver that, to ensure a proper start, cold-start aids for the engine must be used.
Display of fault codes
To display the fault codes, the engine must be stopped, the ignition switch must be set to position “I” and the diagnostic mode must be turned on with the diagnostic check switch.
If there are no active faults, the stop and warning lamps remain on but do not flash. But if active fault codes are present, the ECU begins to display the fault codes.
Before the display of a fault code begins, the warning lamp is switched on; after it goes out, the ECU displays (by flashing) the digit of the active fault code with the stop lamp (short pauses indicate the end of a digit).
Switching the warning lamp on again indicates the start of the display (flashing) of the next digit of the active fault code with the stop lamp (the function of separating the following fault code from the preceding one).
The ECU continues to display the fault code until the user uses the diagnostic switch to change the fault code to the next or previous one.
The management system uses three- and four-digit fault codes. The diagnostic mode remains active until the diagnostic switch is turned off or until the engine is started.
External diagnostic tools
External diagnostic tools include:
- INSITE: a Windows-based computer service tool for Cummins electronic engines. Intended to assist in detecting and eliminating engine faults.
- Generic scanners: the module supports generic scanners via the public data transmission channels J1587 and J1939 for CES 14601.
INSITE enables the user to reproduce both active and inactive fault codes on the display and to erase only inactive fault codes from the ECU. INSITE also provides engine monitoring and offers special diagnostic test tools.
The data transmission channel is activated when the ignition key is set to position “I”, regardless of whether the engine is running or not. The data transmission channel is used with the tools offered by the Cummins company.
Diagnostic fault codes
| Code | Conditions for the code to appear | Result | Possible fault location |
|---|---|---|---|
| 111 | Internal ECU error | The engine may not start | Electronic control unit |
| 115 | Crankshaft and camshaft position sensors — no signal from either, data differ from the specified values, intermittent or incorrect. The ECU identifies the primary and backup position sensor signals as being connected the wrong way round. | The engine may not start | Crankshaft and camshaft sensor wiring crossed |
| 122 | Short circuit to supply in the boost pressure sensor circuit | Reduction in engine power |
|
| 123 | Short circuit to the low-voltage circuit or open circuit in the boost pressure sensor circuit | Reduction in engine power |
|
| 131 | Short circuit to supply in the accelerator pedal position sensor circuit (channel No. 1) | Some reduction in engine power. “Limp-home” mode |
|
| 132 | Short circuit to the low-voltage circuit in the accelerator pedal position sensor circuit (channel No. 1) | Some reduction in engine power. “Limp-home” mode |
|
| 133 | Short circuit to supply in the remote accelerator position sensor circuit | The remote accelerator pedal does not work. The pedal opening degree is set to 0 % |
|
| 134 | Short circuit to the low-voltage circuit in the remote accelerator position sensor circuit | The remote accelerator pedal does not work. The pedal opening degree is set to 0 % |
|
| 135 | Short circuit to supply in the emergency oil pressure sensor circuit | No effect on operation. No engine protection by oil pressure |
|
| 141 | Short circuit to the low-voltage circuit in the emergency oil pressure sensor circuit | No effect on operation. No engine protection by oil pressure |
|
| 143 | Oil pressure below normal | Reduction in engine power | Oil pressure |
| 144 | Short circuit to supply in the coolant temperature sensor circuit | White smoke possible. The fan remains on if it is controlled by the ECU. No engine protection by coolant temperature |
|
| 145 | Short circuit to the low-voltage circuit in the coolant temperature sensor circuit | White smoke possible. The fan remains on if it is controlled by the ECU. No engine protection by coolant temperature | Coolant temperature |
| 146 | Coolant temperature above normal | Reduction in power. Engine shutdown possible if protective shutdown is permitted | Coolant temperature |
| 151 | The engine coolant temperature signal indicates that the engine coolant temperature exceeds the critical engine protection limit | Progressive reduction in power depending on the time the warning signal is on. If protective shutdown is permitted, the engine will be shut down 30 s after the “STOP” indicator begins to flash | Coolant temperature |
| 153 | Short circuit to supply in the intake manifold air temperature sensor circuit | White smoke possible. The fan remains on if it is controlled by the ECU. No engine protection by intake manifold air temperature |
|
| 154 | Short circuit to the low-voltage circuit in the intake manifold air temperature sensor circuit | White smoke possible. The fan remains on if it is controlled by the ECU. No engine protection by intake manifold air temperature |
|
| 155 | The intake manifold air temperature sensor signal indicates that the air temperature exceeds the critical engine protection limit | Progressive reduction in power depending on the time the warning signal is on. If protective shutdown is permitted, the engine will be shut down 30 s after the “STOP” indicator begins to flash |
|
| 175 | Short circuit to supply in the throttle actuator electric motor circuit | The throttle actuator electric motor does not work |
|
| 176 | Short circuit to the low-voltage circuit in the throttle actuator electric motor circuit | The throttle actuator electric motor does not work |
|
| 177 | Throttle actuator electric motor blocked in the open position | The throttle actuator electric motor does not work |
|
| 187 | Short circuit to the low-voltage circuit in sensor supply circuit No. 2 | Reduction in power |
|
| 191 | Short circuit to earth when the air conditioning is switched on | The air conditioning does not switch on | Wiring and connectors |
| 195 | Short circuit to supply in the coolant level sensor circuit | No effect on operation |
|
| 196 | Short circuit to the low-voltage circuit in the coolant level sensor circuit | No effect on operation |
|
| 197 | Low coolant level detected | No effect on operation | Coolant level |
| 212 | Short circuit to supply in the engine oil temperature sensor circuit | No engine protection by engine oil temperature |
|
| 213 | Short circuit to the low-voltage circuit in the engine oil temperature sensor circuit | No engine protection by engine oil temperature |
|
| 214 | The engine oil temperature sensor signal indicates that the oil temperature exceeds the critical engine protection limit | Progressive reduction in power depending on the time of the warning signal. If protective shutdown is permitted, the engine will be shut down 30 s after the “STOP” indicator begins to flash | Engine oil temperature |
| 221 | Short circuit to supply in the atmospheric pressure sensor circuit | Reduction in power |
|
| 227 | Short circuit to supply in sensor supply circuit 2 | Reduction in power | Short circuit to supply |
| 234 | The crankshaft speed sensor signal indicates that the engine speed exceeds the critical engine protection limit | Fuel supply cut off until the engine speed falls to a normal value |
|
| 238 | Short circuit to the low-voltage circuit in sensor supply circuit No. 3 | Difficult starting and uneven running possible | Short circuit to earth |
| 239 | Short circuit to supply in sensor supply circuit No. 3 | Reduction in power | Short circuit to supply |
| 241 | No vehicle speed sensor signal | The engine speed does not exceed the maximum value. Engine speed calculated without the speed sensor. The cruise control, protective downshift engagement and speed limiter systems will not work | Vehicle speed sensor |
| 242 | Signal intermittent or distorted | The engine speed does not exceed the maximum value. Engine speed calculated without the speed sensor. The cruise control, protective downshift engagement and speed limiter systems will not work | Vehicle speed sensor |
| 245 | Short circuit to the low-voltage circuit in the fan electric motor circuit | The fan will remain on continuously or will not work | Short circuit to earth |
| 249 | Short circuit to supply in the outside air temperature sensor circuit | No effect on operation |
|
| 252 | Intermittent signal from the engine oil level sensor | The engine oil level sensor does not work |
|
| 253 | A very low oil level value has been received from the engine oil level sensor | Reduction in power possible. Oil pressure reduction possible, serious engine damage possible |
|
| 254 | Short circuit to the low-voltage circuit in the fuel shut-off solenoid valve circuit | The fuel shut-off solenoid valve is closed, the engine is stopped |
|
| 255 | Short circuit to supply or open circuit in the fuel shut-off solenoid valve circuit | The fuel shut-off solenoid valve may fail to open when the ignition is switched on or fail to close when it is switched off |
|
| 256 | Short circuit to the low-voltage circuit in the outside air temperature sensor circuit | No effect on operation |
|
| 257 | Fuel shut-off solenoid valve blocked in the open position or leaking | Reduction in power, the engine may run briefly when the key is turned to the “OFF” position |
|
| 269 | Attempt to start the engine without authorisation from the anti-theft system | The engine will not start | Immobiliser not deactivated |
| 271 | Short circuit to the low-voltage circuit in the fuel supply control solenoid valve circuit | The engine will run poorly at idle. Reduction in engine power. The fuel pressure will be higher than specified | Short circuit to earth |
| 272 | Short circuit to supply or open circuit in the fuel supply control solenoid valve circuit | The engine will not run or will run poorly | Short circuit to supply |
| 281 | Pumping imbalance between the high-pressure pump plungers | The engine will not start or reduction in power possible | High-pressure fuel pump |
| 285 | The electronic control unit receives the signal from the Multiplex bus too late or does not receive it at all | One or more devices connected to the Multiplex bus are not working properly | Multiplex bus SAE J1939 |
| 286 | The electronic control unit receives only part of the necessary information from the devices connected to the Multiplex bus | At least one device connected to the Multiplex bus is not working properly | Multiplex bus SAE J1939 |
| 287 | The electronic control unit has identified a fault with the accelerator pedal | The engine runs only at idle or does not run at full output | Multiplex bus SAE J1939 |
| 288 | The electronic control unit has identified a fault with the remote accelerator pedal | The engine does not respond to the remote pedal. The engine runs only at idle. Only the cab accelerator pedal can be used | Multiplex bus SAE J1939 |
| 291 | The anti-theft system cannot work properly | The engine may not start |
|
| 295 | The electronic control unit has recorded an error in the atmospheric pressure sensor signal | Reduction in power |
|
| 311, 313, 315, 319, 321, 322, 324, 331, 332, 334, 343, 346, 351, 352, 356, 357, 358, 386, 415, 418, 425, 427, 428, 429, 435, 436, 441, 442, 449, 451, 452, 465, 466, 471, 477, 478, 491, 492, 498, 499, 545, 553, 554, 555, 556, 559, 584, 585, 596, 597, 598, 649 (fault codes 311–649 are presented in the full version of the table) |
*The continuation of the fault code table is presented in the full version of the document* | ||
Note: The continuation of the Cummins ISF3.8 fault code table is presented in the article — Continuation of the fault code table.
