Alfa Romeo cars are mainly equipped with Bosch control systems, including: Bosch Motronic ML4.1, 1.7, 2.10.3 / 4, MP3 versions. 1, as well as Multec XM and Weber IAF 8F 6B. All Alfa systems control the primary circuit of the ignition system, the fuel injectors and the idling system from one unit.
Engine control systems have a self-diagnostic function that continuously analyzes the signals of the sensors and actuators of the engine and compares them with the reference values. If the diagnostic program detects a mismatch, one or more corresponding fault codes are recorded in the memory of the electronic control unit (BLU). Codes will not appear in cases where the defective item is not under the control of the ACM and when a bad situation is not provided for by its software.
In these systems, the electronic control unit generates 4-digit "flashing" codes for manual reading. When extracting these codes with the reader, the numbers displayed on its display can be completely different. Further codes are given, which are obtained both with the help of a flashing light bulb, and with the help of a reader. When diagnosing, use the appropriate column of the table, depending on the method of reading.
The Alfa-Romeo software does not generate digital trouble codes for systems other than Bosch Motronic ML4.1 and 1.7. The reader reproduces the fault on the screen without accessing the codes. Although the digital code is not available, a malfunction of the system program, if it appears, will be fixed and stored in memory.
The Alfa-Romeo system has a mode of limited controllability (a function known as "limp home" or "crash home"). This means that if some malfunctions occur (not all malfunctions cause this mode to be activated), the engine control system is guided not by the sensor reading, but by its reference value. This mode allows the car to reach the garage or service station for inspection and repair, albeit with less efficiency. After troubleshooting, the system returns to normal operation.
All Alfa-Romeo systems have the ability to adapt, in which the programmed parameter values for some sensors and actuators change during operation, taking into account engine wear for maximum control efficiency.
Models for the USA, in accordance with national requirements, are equipped with a warning light bulb "Check Engine" located in the instrument panel. With the same bulb, it is also possible to extract trouble codes that can lead to a deterioration in the exhaust composition. Models for the European market are not equipped with such an alarm system.
Two diagnostic connectors are located in the passenger compartment under the dashboard. The 3-pin connector is for connecting the code reader (see Figure 5.1), and the 4-pin connector for reading the "flashing" codes.
To read the code in any way intended 3-pin connector located generally under the dashboard on the passenger side next to the ECU.
The 3-pin connector is only for connecting the reader. It can be located in the engine compartment on the right wing or in the center console next to the ECU or under the dashboard on the driver's side or the passenger side next to the ECU.
In other ECU systems - "flashing" codes are not provided. It is necessary to use the code reader.
To check the actuators of other systems, a code reader is needed.
"Flashing" code |
Reader |
Malfunction |
00000000 |
— |
Horses passing codes |
1000 |
— |
End of transmission codes |
1211 |
037 |
Battery |
1212 |
052 |
Limit sensor throttle |
1213 |
053 |
Limit sensor throttle |
1214 |
045 |
Sensor or the temperature sensor circuit |
1215 |
043 |
With the regulator or his chain |
1216 |
012 |
Potentiometer throttle |
1221 |
007 |
Air flow sensor or with damper |
1222 |
004 |
The idling speed control valve or |
1223 |
010 |
Oxygen sensor or its circuit |
1224 |
028 |
Oxygen sensor or its circuit |
1225 |
044 |
Air temperature sensor or |
1226 |
100 |
Electronic control unit (LPG) |
1227 |
— |
Nozzles or their chain |
1228 |
— |
Nozzles or their chain |
1229 |
— |
Heater control system |
1231 |
031 |
Speedometer signal is automatic |
1232 |
032 |
Injector (1 and 3 for 4-cylinder |
1233 |
002 |
Nozzles (2 and 4 for 4-cylinder |
1234 |
013 |
Automatic transmission or |
1235 |
085 |
A/c or |
1236 |
021 |
Activation of the compressor of air conditioner |
1243 |
1003 |
The fuel pump relay or his chain |
1244 |
034 |
Purge valve carbon filter |
1245 |
023 |
The Executive mechanism of automatic |
1251 |
001 |
Electronic control unit (LPG) |
1252 |
009 |
Crank angle sensor |
1254 |
— |
Potentiometer throttle |
1255 |
— |
Camshaft position sensor |
1265 |
015 |
Diagnostic indicator lamp |
2111 |
— |
Knock sensor 1 circuit or its |
2112 |
— |
Knock sensor 2 circuit or its |
2113 |
— |
Electronic control unit (LPG) |
2116 |
— |
Electronic control unit (LPG) |
444 |
— |
LPG contains no fault codes |
The Alfa-Romeo software does not generate digital trouble codes for systems other than Bosch Motronic ML4.1 and 1.7. The code reader reproduces the fault on the screen without accessing the codes. Although the digital code is not available, a malfunction of the system program, if it appears, will be fixed and stored in memory.