SELF-DIAGNOSTICS FEATURE
DME/Motronic control unit has a self-diagnostic feature with internal memory. Self-diagnostic feature detects malfunctions in control unit or emission-related components and stores fault codes.
DME/Motronic control unit provides a substitute value if a failure occurs in engine (coolant) temperature sensor, intake air temperature sensor, airflow meter or exhaust gas oxygen sensor. These substitute values are canceled when normal engine operation is resumed. To aid in trouble shooting, stored fault codes and sensor values can be monitored via control unit when components are actuated.
In addition to control of relevant systems, DME/Motronic control unit can supply or receive data for diagnostic procedures. Data can be read out or entered with BMW MoDIC (hand-held scan tester) or BMW Service Tester (Sun 2013 Engine Analyzer) and applicable BMW diagnostic software.
Data exchange between control unit and BMW diagnostic software occurs via Diagnostic Initiation Line (RxD) and Diagnostic Data Line (TxD) in engine diagnostic (connector) socket. (Scheme 6)
After installing diagnostic software in BMW Service Tester, general overview of DME/Motronic control unit appears on display screen. Self-diagnostic procedure is initiated by selecting relevant control unit; corresponding diagnostic program functions are automatically assigned from diagnostic software.
Note. To avoid faults during vehicle operation, RxD line is connected to battery voltage and TxD line to ground when diagnostic (connector) socket cover is closed.
Scheme 6
READ STATUS Diagnostic Function
This function permits technician to read statuses and current input/output values being received/sent out by DME/Motronic control unit. This display must be compared with actual status of vehicle. If a signal is found to be defective or if status detected by control unit deviates from actual status of vehicle, trouble shooting must be carried out at associated input or output (voltage, resistance, etc.).
DRIVE COMPONENTS Diagnostic Function
This function allows technician to drive (actuate) component without DME/Motronic control unit switch-on condition being set. Actual statuses of inputs at control unit are ignored. With this function, proper operation of components can be checked with components installed.
READ DEFECT CODE MEMORY Diagnostic Function
Contents of DME/Motronic control unit defect code memory and operating conditions under which defect occurred can be accessed via this function. More extensive trouble shooting is then carried out in accordance with instructions provided in diagnostic program or diagnostic procedure.
Note. On 325i, 325is, and 525i (DME 3.1), fault codes (except Codes 26 and 200) are stored after engine has started. If several codes have been stored, they appear in chronological order.
QUICK TEST Function
QUICK TEST permits checking of defect codes on all control units with a self-diagnostic feature. Ignition switch must be turned to ON position before QUICK TEST is started. QUICK TEST is started from general overview of DME/Motronic control unit screen and is indicated by "QUICK TEST ACTIVE" in last (screen) line.
Control units are read out in same sequence as control unit overview. Progression of QUICK TEST is indicated to technician by flashing relevant line of control unit overview. Continuation to second page of control unit overview takes place automatically.
When BMW diagnostic software finds a control unit, corresponding line of DME/Motronic control unit overview is marked by an asterisk (*). If a defect code is stored in control unit, line is highlighted. QUICK TEST can be canceled at any time by pressing any key on BMW Service Tester. Completion of QUICK TEST is indicated by "QUICK TEST COMPLETED" in last (screen) line.
Reading Diagnostic (Flash) Codes
- With ignition switch in RUN position and after depressing accelerator pedal 5 times to WOT, CHECK ENGINE light comes on for 5 seconds to indicate self-diagnostic feature is preparing to output diagnostic codes. (Scheme 7)
- CHECK ENGINE light then turns off for 0.5 second (awaiting synchronization signal), comes on for 2.5 seconds (light check) and again turns off for 2.5 seconds (wait for readout). Last 2.5 second pause tells technician to wait for diagnostic code readout.
- Next CHECK ENGINE light on/off periods represent diagnostic codes stored. CHECK ENGINE light will be on or off for 0.5 second with a 2.5 second pause between each code digit and a 2.5 second pause between each code. (Scheme 7)
Scheme 7
| Code | Component Malfunction | Diagnosis |
|---|---|---|
| 1211 | Digital Motor Electronics (DME) Control Unit | Code indicates failure of DME. Erase stored codes. Start and run vehicle for 30 seconds. Turn ignition off for 30 seconds. If code reoccurs, replace DME. |
| 1212 | Oxygen Sensor No. 2 | Code indicates oxygen sensor signal is out of range or not present at an engine temperature of 158°F (70°C) or more. Check wiring and sensor. Sensor voltage should be 0.02-0.85 volt. |
| 1213 | Oxygen Sensor Control No. 2 | Code indicates DME has detected excessive variation in air-fuel (rich/lean) mixture for greater than 10 seconds. Possible causes include no fuel, inadequate fuel pressure, injector defective, temperature sensor defective, secondary air leak, EVAP system defective, airflow meter defective or engine mechanical problem. |
| 1215 | Mass Airflow Sensor | Code indicates an open or short to voltage or ground at mass airflow sensor or wiring. Check airflow sensor wiring and connections. |
| 1216 | Throttle Position Sensor | Code indicates an open or short to voltage or ground at throttle position sensor or wiring. Check throttle position sensor wiring and connections. |
| 1218 | Output Stage (Bank 1) | Code indicates an open or short to voltage at output amplifier stage (bank 1). Code may be caused by idle speed actuator, EVAP, control valve, CHECK ENGINE light, injectors, ignition coil(s), oxygen sensor heater relay, or EKP relay. Delete code after checking for other faults. Erase code. If code reoccurs, erase code again and reset DME by disconnecting its connector for at least 5 minutes. If code reoccurs and no other problems are present, replace DME. |
| 1219 | Output Stage (Bank 2) | Code indicates an open or short to voltage at output amplifier stage (bank 2). Code may be caused by idle speed actuator, EVAP, control valve, CHECK ENGINE light, injectors, ignition coil(s), oxygen sensor heater relay, or EKP relay. Delete code after checking for other faults. Erase code. If code reoccurs, erase code again and reset DME by disconnecting its connector for at least 5 minutes. If code reoccurs and no other problems are present, replace DME. |
| 1221 | Oxygen Sensor 1 | Code indicates oxygen sensor signal is out of range or not present at an engine temperature of 158°F (70°C) or more. Check wiring and sensor. Sensor voltage should be 0.02-0.85 volt. |
| 1222 | Lambda Control 1 | Code indicates DME has detected excessive variation in air-fuel (rich/lean) mixture for greater than 10 seconds. Possible causes include no fuel, inadequate fuel pressure, injector defective, temperature sensor defective, secondary air leak, EVAP system defective, airflow meter defective or engine mechanical problem. |
| 1223 | Coolant Temperature Sensor | Code indicates an open or short to voltage or ground at coolant temperature sensor or wiring. Check sensor wiring and connections. Sensor value should be 8.3-10.6 k/Ohms at 14°F (-10°C), 2.2-2.7 k/Ohms at 68°F (20°C), and 2.9-3.6 k/Ohms at 140°F (60°C). |
| 1224 | Intake Air Temperature Sensor | Code indicates an open or short to voltage or ground at intake air temperature sensor or wiring. Check sensor wiring and connections. Sensor value should be 2.2-2.7 k/Ohms at 68°F (20°C), and 7.6-9.0 k/Ohms at 122°F (50°C). |
| 1225 | Knock Sensor No. 1 | Code indicates an open or short to voltage or ground at knock sensor No. 1 or its wiring. Check sensor, sensor wiring and connections. Check fuel octane and possible carbon in cylinders. |
| 1226 | Knock Sensor No. 2 | Code indicates an open or short to voltage or ground at knock sensor No. 2 or its wiring. Check sensor, sensor wiring and connections. Check fuel octane and possible carbon in cylinders. |
| 1227 | Knock Sensor No. 3 | Code indicates an open or short to voltage or ground at knock sensor No. 3 or its wiring. Check sensor, sensor wiring and connections. Check fuel octane and possible carbon in cylinders. |
| 1228 | Knock Sensor No. 4 | Code indicates an open or short to voltage or ground at knock sensor No. 3 or its wiring. Check sensor, sensor wiring and connections. Check fuel octane and possible carbon in cylinders. |
| 1231 | Battery Voltage Or DME Main Relay | Check charging system and/or battery. |
| 1232 | Idle Throttle Valve Switch | Code indicates an open or short to voltage or ground at idle throttle valve switch or wiring. Check idle throttle valve switch wiring and connections. |
| 1233 | Full Load Throttle Valve Switch | Code indicates an open or short to voltage or ground at full load throttle valve switch or wiring. Check throttle position sensor wiring and connections. |
| 1234 | Vehicle Speed Sensor | Code indicates an open or short to voltage or ground in speed sensor wiring to DME, or speedometer malfunction. |
| 1237 | A/C Compressor Cut-Off | Code indicates an open or short to voltage or ground in A/C cut-out relay wiring or defective relay. |
| 1241 | Air Mass Sensor (HFM) | Observe load signal with scan tool. The nominal value is 1.8-2.2 ms when the battery is charged, air conditioning switched off and gear selector lever in position P or N. If the nominal value is not achieved, check voltage supply of air mass sensor, wires and connector. If voltage supply, wires and connector are okay, check air mass sensor. |
| 1242 | A/C Compressor | Code indicates an open or short to voltage or ground in A/C compressor signal wire to DME. Check A/C belt and refrigerant charge. |
| 1243 | Crankshaft Position Sensor | Code indicates an open or short to voltage or ground in crankshaft position sensor wiring, or defective sensor. |
| 1244 | Camshaft Position Sensor | Code indicates an open or short to voltage or ground in camshaft position sensor wiring, or defective sensor or coil(s). |
| 1245 | EGS | Code indicates a short to ground in wiring between EGS and DME. |
| 1247 | Ignition Secondary Monitor | Diagnosis is not available. |
| 1251 | Injector No. 1 (Group 1) | Check injector wiring. Check injector for proper operation and spray. |
| 1252 | Injector No. 2 (Group 2) | Check injector wiring. Check injector for proper operation and spray. |
| 1253 | Injector No. 3 | Check injector wiring. Check injector for proper operation and spray. |
| 1254 | Injector No. 4 | Check injector wiring. Check injector for proper operation and spray. |
| 1255 | Injector No. 5 | Check injector wiring. Check injector for proper operation and spray. |
| 1256 | Injector No. 6 | Check injector wiring. Check injector for proper operation and spray. |
| 1257 | Injector No. 7 | Check injector wiring. Check injector for proper operation and spray. |
| 1258 | Injector No. 8 | Check injector wiring. Check injector for proper operation and spray. |
| 1261 | Fuel Pump Relay | Code indicates an open or short to voltage or ground in fuel pump relay pin No. 3 |
| 1262 | Idle Speed Actuator | Code indicates an open or short to voltage or ground in wiring to idle actuator from DME, or output stage of DME is defective. |
| 1263 | Purge Valve | Code indicates an open or short to voltage or ground in wiring to EVAP control valve, or output stage of DME is defective. |
| 1264 | Lambda Heater | Code indicates an open or short to voltage or ground in wiring to DME, lambda sensor heater, heater relay or air pump relay. |
| 1265 | CHECK ENGINE Light | Code indicates an open or short to voltage or ground in CHECK ENGINE light wiring, or bulb is defective. |
| 1266 | VANOS | Code indicates an open or short to voltage or ground in wiring to VANOS relay or defective relay. |
| 1267 | Air Pump Relay | Code indicates an open or short to voltage in wiring between DME and air pump relay, or defective air pump relay. |
| 1271 | Ignition Coil No. 1 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1272 | Ignition Coil No. 2 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1273 | Ignition Coil No. 3 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1274 | Ignition Coil No. 4 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1275 | Ignition Coil No. 5 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1276 | Ignition Coil No. 6 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1277 | Ignition Coil No. 7 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1278 | Ignition Coil No. 8 | Code indicates an open or short to voltage in ignition final stage wiring. |
| 1281 | DME Memory | Code indicates a problem in DME memory. Check for a low battery voltage problem and repair as necessary. Erase code and reconnect DME. If code reoccurs, replace DME. |
| 1282 | Code Memory | Code indicates an incorrect code has been set in memory. Erase code and disconnect a monitored component. If code reoccurs, replace DME. |
| 1283 | Injector Output Stage | Code indicates an intermittent open or short circuit to voltage at an injector, injector wiring or defective DME injector stage. |
| 1286 | Knock Sensor Test Pulse | Code indicates an internal pulse was not detected in DME. Check knock sensor wiring and knock sensors. |
| 1444 | No Fault | — |
DIAGNOSTIC (FLASH) CODES
TROUBLE CODE DEFINITION
| Fault Codes | Affected Circuit | Probable Cause |
|---|---|---|
| 0 | Undefined Defect | (1) Undefined Defect Code Has Been Stored In Defect Code Memory |
| 1 | Fuel Pump Relay | Shorted/Open Relay Or Circuit To DME Control Unit Pin No. 1 |
| 2 | Idle Speed Actuator (Close) | (2) Shorted/Open Actuator Or Circuit To DME Control Unit Pin No. 2 |
| 3 | Fuel Injector (No. 1) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 3 |
| 4 | Fuel Injector (No. 3) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 4 |
| 5 | Fuel Injector (No. 2) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 5 |
| 6 | Fuel Injectors (Output Signal) | (4) Shorted/Open Injector Or Circuit To DME Control Unit |
| 8 | CHECK ENGINE Light | Shorted/Open Indicator Light Or Its Circuit Wiring |
| 12 | Throttle Potentiometer (TPS) | Shorted/Open Circuit In Sensor Or Its Circuit Wiring |
| 16 | Camshaft (Pulse) Sensor | (5) Camshaft (Pulse) Sensor Signal Interrupted Or Faulty |
| 18 | Output Stage (Signal) | (1) Shorted Circuit To Ground/Battery Voltage At DME Control Unit Pin No. 18 |
| 19 | Output Stage (Signal) | (1) Shorted Circuit To Ground/Battery Voltage At DME Control Unit Pin No. 19 |
| 23 | Ignition Coil (Cylinder No. 2) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 2 (Pin No. 23) |
| 24 | Ignition Coil (Cylinder No. 3) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 3 (Pin No. 24) |
| 25 | Ignition Coil (Cylinder No. 1) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 1 (Pin No. 25) |
| 26 | DME Power Supply (B+) | Voltage Input Less Than Battery Voltage (Engine Off) |
| 29 | Idle Speed Actuator (Open) | (2) Shorted Actuator/Circuit To DME Control Unit Pin No. 29, Output Signal Faulty |
| 31 | Fuel Injector (No. 5) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 31 |
| 32 | Fuel Injector (No. 6) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 32 |
| 33 | Fuel Injector (No. 4) | (3) (4) Shorted/Open Injector Or Circuit To DME Control Unit Pin No. 33 |
| 34 | Output Stage (Signal) | (6) Shorted/Open Component Or Circuit To DME Control Unit |
| 36 | Fuel Tank Vent (Evaporation) Control | Shorted/Open Fuel Evaporation Control Valve Or Circuit To DME Control Unit |
| 37 | Oxygen Sensor Heater | Shorted/Open Oxygen Sensor/Heating Element Circuit To DME Control Unit |
| 41 | Air Mass (Sensor) Meter | Shorted/Open Air Mass Sensor Or Its Circuit Wiring |
| 46 | Output Stage (Signal) | (1) Shorted Circuit To Ground/Battery Voltage At Dme Control Unit Pin No. 46 |
| 48 | A/C Compressor Shutoff | (1) (7) A/C Compressor Not Switched Off At Speed Less Than 5 MPH |
| 50 | Ignition Coil (Cylinder No. 4) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 4 (Pin No. 50) |
| 51 | Ignition Coil (Cylinder No. 6) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 6 (Pin No. 51) |
| 52 | Ignition Coil (Cylinder No. 5) | (1) Open Circuit In Ignition Output Signal For Cylinder No. 5 (Pin No. 52) |
| 54 | DME Power Supply | Voltage To DME Control Unit Drops Below 10 Volts Or Exceeds 14 Volts |
| 55 | Ignition Output Stage (Signal) | (1) Open Circuit, Defect Could Not Be Assigned To Any Specific Cylinder |
| 64 | Ignition Timing Intervention | (8) Short To Ground In Circuit To DME Control Unit Pin No. 64 |
| 67 | Crankshaft (Speed/ Position) Sensor | (1) No Sensor Signal, Ignition And Fuel Injection Are Turned Off |
| 70 | Oxygen Sensor | Shorted/Open Circuit On Oxygen Sensor Or Its Circuit Wiring |
| 73 | Vehicle Speed Sensor | (9) Faulty Vehicle Speed Sensor Signal |
| 77 | Intake Air Temp. Sensor | Shorted/Open Circuit In Sensor Or Its Circuit Wiring |
| 78 | Engine (Coolant) Temp. Sensor | Shorted/Open Circuit On Sensor Or Its Circuit Wiring |
| 81 | Anti-Theft (DWA) Signal | Anti-Theft System Is Detected As Being On After Engine Has Started |
| 85 | A/C Compressor | A/C Compressor Is Detected As Being On And A/C Switch Signal Is Not Received |
| 100 | Output Stage (Signal) | (1) Shorted Circuit To Ground/Battery Voltage At DME Control Unit Pin No. 100 |
| 200 | DME Control Unit | Code Is Set When An Internal Defect Is Found In RAM Or ROM/EPROM |
| 201 | Defect (Fault) Code Memory | Code Is Set If Illogical Data Are Stored In Defect Code Memory |
| 202 | Emission Control | Emission Controls Out Of Range, No Air/Fuel Mixture Related Problem Is Detected |
| (1) Fault codes applicable to 325 models only. (2) Fault Code 29 is also stored when connection to idle actuator or power supply is interrupted. Fault Codes 2 and 29 are also stored when engine operation is interrupted without ignition being switched off. Defect is then detected at an engine speed less than 600 RPM. (3) Fault Code 6 may also be stored as pin No. 6 is connected to all injectors. (4) Fault Code 6 can be ignored if a code for a specific injector is stored. (5) Simultaneous activation of ALL ignition coils takes place when camshaft sensor signal is interrupted. (6) Components/circuits affected are: idle speed actuator, oxygen sensor heater relay, fuel evaporation control, fuel pump relay, CHECK ENGINE light. Fault Code 34 can be ignored if a code for a specific injector is stored. (7) Fault described occurs when circuit is shorted to ground. When circuit is shorted to battery voltage, A/C compressor never operates (engages). (8) Fault code is set when wiring from control unit pin No. 64 to electronic transmission control (EGS) unit has a short to ground for at least 2.5 seconds. Ignition timing is adjusted in retard direction only once, after which this signal is ignored. (9) Code is set when engine speed is greater than 4500 RPM at high loads for a minimum of 10 seconds. | ||
| (1) | Fault codes applicable to 325 models only. |
| (2) | Fault Code 29 is also stored when connection to idle actuator or power supply is interrupted. Fault Codes 2 and 29 are also stored when engine operation is interrupted without ignition being switched off. Defect is then detected at an engine speed less than 600 RPM. |
| (3) | Fault Code 6 may also be stored as pin No. 6 is connected to all injectors. |
| (4) | Fault Code 6 can be ignored if a code for a specific injector is stored. |
| (5) | Simultaneous activation of ALL ignition coils takes place when camshaft sensor signal is interrupted. |
| (6) | Components/circuits affected are: idle speed actuator, oxygen sensor heater relay, fuel evaporation control, fuel pump relay, CHECK ENGINE light. Fault Code 34 can be ignored if a code for a specific injector is stored. |
| (7) | Fault described occurs when circuit is shorted to ground. When circuit is shorted to battery voltage, A/C compressor never operates (engages). |
| (8) | Fault code is set when wiring from control unit pin No. 64 to electronic transmission control (EGS) unit has a short to ground for at least 2.5 seconds. Ignition timing is adjusted in retard direction only once, after which this signal is ignored. |
| (9) | Code is set when engine speed is greater than 4500 RPM at high loads for a minimum of 10 seconds. |
325 SERIES & 525i (DME 3.1) FAULT CODE IDENTIFICATION