You may have heard about the “Stomp Test” that can tell you what trouble codes are stored in your vintage BMW’s engine computer. Unlike modern OBD II cars (from 1995 onward) that use a scan tool plugged into the OBD II port, older cars system is classified as OBD I. Some cars have this OBD I diagnostic port under the hood which can allow for a tool to scan for codes.
Fortunately for classic BMW drivers in the US, there is the Stomp Test. This works on cars with Bosch Motronic 1.3 or later, which is in model year 1988 cars and up. If you have a 1987 model year BMW, it may be on the cusp, so it depends on what ECU is in the car and its production date. I have been told this test does not work on European or Euro Spec cars, though have not confirmed myself.
How To perform the Stomp Test:
- Turn the ignition to position two. That’s the second click on turning the key. Do not start the car.
- Press the gas pedal to the floor five times within 5 or 6 seconds.
- After one flash of the check engine light, the process will begin.
- Engine light will flash a four digit code using morse code to communicate the trouble code, if one exists.
- It is helpful to keep a pen and pad to note the numbers displayed.
- Refer to the list of trouble codes here to begin diagnosis
OBDI BMW Trouble Codes for Classic BMW Cars
1211 DME control unit did not pass self-test. Disconnect from power and reconnect after 10 minutes.
1212 Oxygen (O2 or Lambda) Sensor 2 (cylinders 4–6)
1213 Lambda Control System Bank 2: The ECM has been unable to maintain Lambda (fuel mixture or fuel trim) on Bank 2 (cylinders 4–6) of the engine.
1215 Air mass/volume sensor
1216 Throttle potentiometer
1218 “Output Stage, Group 1”
1219 “Output Stage, Group 2”
1221 Oxygen (O2 or Lambda) sensor
1222 Lambda Control System Bank 1: The ECM has been unable to maintain Lambda (fuel mixture or fuel trim) on Bank 1 (cylinders 1–3) of engine.
1223 Coolant temperature sensor
1224 Intake air temperature sensor
1225 Knock sensor 1
1226 Knock sensor 2
1227 Knock sensor 3
1228 Knock sensor 4
1231 Battery voltage/DME main relay
1232 Throttle switch—idle
1233 Throttle switch—WOT
1234 Speedometer A Signal
1237 A/C compressor cut off
1241 False air mass sensor code—update the EPROM and replace the idle valve
1242 A/C compressor
1243 Crankshaft pulse sensor
1244 Camshaft sensor
1245 Intervention EGS
1247 Ignition secondary monitor
1251 Fuel injector 1 (or group 1)
1252 Fuel injector 2 (or group 2)
1253 Fuel injector 3
1254 Fuel injector 4
1255 Fuel injector 5
1256 Fuel injector 6
1257 Fuel injector 7
1258 Fuel injector 8
1261 Fuel pump relay control
1263 Purge valve
1264 Oxygen (O2 or Lambda) heater
1265 Fault lamp (check engine)
1267 Air pump relay control
1271 Ignition coil 1
1272 Ignition coil 2
1273 Ignition coil 3
1274 Ignition coil 4
1275 Ignition coil 5
1276 Ignition coil 6
1277 Ignition coil 7
1278 Ignition coil 8
1281 Control unit memory supply
1282 Fault code memory did not pass self-test. Disconnect from power and reconnect
after 10 minutes. Check charging system for over-voltage.
1283 Fuel injector output stage (can be set by a faulty ignition coil)
1286 Knock control test pulse
1444 No failures
One caveat to this is for the special V12 cars like the 750i, 750iL, 850i. They have two banks of cylinders, and each one has its own ECU. To access the second ECU complete the same steps as above, but press gas pedal 6 times (not 5). Each code for the second bank will begin with the number 2.
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