Motronic Fault Codes

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Overview

BMW E30s from 1988 onwards have Bosch Motronic versions M1.1, M1.3 and M.7 and can display fault diagnostic codes. These can be used to identify faults in the system.

NOTE: THESE CODES ARE NOT RELEVANT FOR UK CARS. THEY ARE ONLY RELEVANT FOR CARS WITH THE "ENGINE CHECK" LIGHT

Procedure

For safety reasons, put the transmission in neutral, and turn the ignition key to "On" position but do not start the car In quick succession fully depress and release accelerator pedal 5 (five) times

After a couple of seconds the Check Engine light will blink once, and start to flash code(s)

All codes are composed of 4 digits (see table below). For example, code 1211 is represented as Blink, pause, Blink Blink, pause, Blink, pause, Blink

When code(s) start to repeat, all of them have been displayed

Fault Codes

Code Error Description
1211 DME Control Unit DME, Motronic computer, related fault - which may indicate problem with car computer itself. Delete any stored codes and perform following test: Start the car and let it run for 30 seconds; Turn off car and let it sit for another 30 seconds; Perform diagnostic test again; If the same flash code re-appears DME should be replaced
1215 Air Mass/Volume Sensor Indicates problem relating to Air / Mass Flow Meter - AFM or MAF depending on your e30 model. Causes could be cable wire damage, short circuit in the unit, or air / vacuum leak (check air intake hose - big L-shaped one)
1216 Throttle Potentiometer Designates error with potentiometer in Throttle Position sensor. Some later model cars have potentiometer, as opposed to switch (TPS) found on majority of e30 s. This code will be active if inappropriate sensor values are read by control unit, and although presence of this fault code may indicate bad potentiometer, wire harness connection at the sensor is common issue (corroded, loose connection, or broken).
1221 EGO Sensor #1 Fault related to Oxygen ( O2 ) sensor is present if the sensor is unplugged, bad / not-operational, or sensor values are out of range. Test the O2 sensor for proper operation, as well as check harness connections by the sensor and by the battery tray in the engine compartment.
1222 Lambda Control #1 Lambda control fault code is produced when Motronic system in Bosch control unit receives signal indicating that air/fuel mixture is either excessively rich or excessively lean for period of time loner then 10 seconds. Majority of the causes that affect drivability of the car can be responsible for DME flashing this error:

air leak defective Air Flow Meter ( AFM) bad engine temperature sensor incorrect fuel pressure problem with injector(s) defective evaporation system empty gas tank issue with spark plugs problem with valves etc.

1223 Coolant Temp. Sensor This fault code indicates problem relating to Coolant Temperature Sensor (CTS). Test the CTS sensor for proper functionality and check sensor wiring and connections.
1224 Intake Air Temp. Sensor Fault with Air Temperature Sensor , which can indicate bad sensor, break or short in wires
1231 Battery Voltage / DME Main Relay Battery Voltage / DME Main Relay error code can mean that battery voltage is out of range (either too high or too low), or that battery was disconnected. Test charging system and /or battery to find problem cause.
1232 Throttle Idle Switch Error associated with "idle" portion of Throttle Position Switch. Test TPS for proper operation.
1233 Throttle WOT Switch Error associated with "WOT" (Wide Open Throttle) portion of Throttle Position Switch. Test TPS for proper operation.
1251 Fuel Injectors (group #1) Fuel Injectors (group #1) fault can indicate problem with either individual injector or first group of injectors. Solution is to check fuel injector connectors, wiring from DME to injectors, and to test injector(s) for proper spray pattern. Additionally, fault code 1283 could be set in conjunction with this one.
1252 Fuel Injectors (group #2) Same as 1251
1261 Fuel Pump Relay Control Fuel Pump Relay Control code indicates break or short circuit associated with fuel pump relay. Test for proper signal on number 3 pin on DME. It can also mean that output stage of DME is faulty (Motronic version 1.3 only)
1262 Idle Speed Actuator Possible causes for Idle Speed Control fault are:

damaged wiring to the idle speed actuator wire from DME is defective output stage of DME is damaged Also if engine stalls while it is above 600 RPM, code 1262 will be set

1263 Purge Valve Purge Valve fault can indicate that Evaporative Control Valve is faulty, that wire from DME to the valve is damaged, or problem with output stage of DME (Motronic version 1.3 only)
1264 EGO Heater EGO Heater error code is stored if there is fault with Oxygen Sensor Heather or it's relay , Air Pump relay, supply wiring, or wire from DME
1444 No Failure No errors