These codes can be understood if following the directions in the previous section. See Table 23
34.2 ENGINE STOMP TEST
The engine stomp test is the most popular and cheapest ways to obtain the code that your engine is displaying. You can always buy a code reader that goes in your diagnostic port, but the manual process is very simple and straightforward.
1. The fault codes will appear on the check engine light when you turn the ignition key to the “On” position. Do not start the car.
2. Fully depress the accelerator pedal, then fully release it.
3. Repeat this process 5 times fairly quickly within a 5 second window. (You are engaging the wide open throttle switch then the idle switch each 5 times).
4. This signals the Motronic unit to send the fault codes by flashing the Check Engine light in succession.
5. You should see the light flash once (long flash) then it will start flashing the 4 digit codes (shorter flashes).
6. If there are no faults, you should see the 1444 code.
a. Signified by Bliiiiiiiiiiiink (initiating code) - - - wait - - - blink - -wait - - blink, blink, blink, blink- - wait - - blink, blink, blink, blink- - wait - - blink, blink, blink, blink - - - - - Bliiiiiiiiiiiink (completing code)
7. The codes appear as a series of flashes for each digit.
8. The flashes indicating one digit are about 1 second apart, the next digit appears after a couple second interval. Step 6 has a good example
34.3 ADDRESSING POPULAR MOTRONIC CODES
A lot of these codes are self-explanatory and can be addressed by a simple google search, but I’d like to share a few that I’ve had personal experience with. Obviously some of the codes above do not apply to the E30 or M30 such as VANOS, or sometimes anything dealing with the A/C if you don’t have A/C. 1221/1212 – Oxygen Sensor – I’ve had an oxygen sensor code and was skeptical because it was accompanied by Lambda Control, which I’ll explain in a second. I ended up replacing the oxygen sensor and it fixed the problem. No Lambda Control problems and no more oxygen sensor code. 1222/1213 – Lambda Control - This is the dreaded code shared among most E30 & M30 enthusiasts. The Lambda code means that “something is wrong with your air fuel ratio” and it is logged into the ECU as an AFR that diverts from nominal for more than 10 seconds. In other words, your air fuel ratio is either too rich or too lean for too long of a timespan. Pretty general, huh? What could the problem possibly be? Well, starting with a vacuum leak is a good idea, but here is a list of common things you should check between the E30 chassis & M30 engine to try to address a Lambda Code issue.
Vacuum Leak – Check for the carbon canister, fuel lines, any of the 3 or 4 vacuum hoses on the engine intake. If there are any cracks in the hoses, including the intake boot, replace it with new.
Fuel Pressure – Check the fuel pressure at both the pump & at the engine. Make sure that fuel is flowing properly from the pump to the regulator. If necessary, you might have a clogged fuel filter or even a clogged line if the E30 you’re swapping into has been sitting for a long time.
Idle Control Valve – Swap with a known working unit. Clean with brake cleaner to make sure that the flapper inside moves freely. Test by unplugging the ICV when the car is idling. The idle should shoot up. TPS – Make sure that the resistance values are per the Bentley manual for both closed, open throttle, and all in between. Coolant Temp Sensor (blue tip) – This could, if faulty, send the wrong signals to your fuel injectors. Make sure that the resistance values are correct according to the temperature of your engine. Air Flow Meter – Make sure that the M30 air flow meter is properly registering the correct resistance values when the flapper is open and closed and all in between. Is the carbon canister working properly? Check the electrical connections. Oxygen sensor – Is it working properly? How old is it? Where is it mounted in your exhaust? Is it too far from the headers to be heated enough to read properly?
34.4 RESETTING ENGINE CODES
Unplug the battery for 5 minutes and re-plug. Codes should go away unless of course, you didn’t fix the problem!