So I just replaced the injectors on my 1993 190E 2.6. In the process of that, I removed my EHA to inspect it to see if it had failed externally as I was smelling gas at the front of the engine. I couldn't see any cracks so I reinstalled it and had a slow leak so I thought it was the o-rings, changed those, but the leak got worse. I figured that the unit may have failed internally so I grabbed the EHA off of the engine in my parts car and installed it and it didn't leak. It took some work to get the engine to start after I put that one on (probably air in the system) and for some reason in the process I decided to unplug the idle speed air valve. After doing all of this, my car ran much better but my CEL keeps on coming on (sometimes it goes away if I shut off the car and restart, sometimes it doesn't). I have to take this in very soon to have the catalytic converter replaced so I can pass emissions so I decided to look into what could be causing the CEL light to flash. I then figured out how to get the codes from the OBD system, I thought you had to have a special reader (seen it advertised on this forum) but then read about the LED light and button.

I read the codes then cleared them. I'll drive around tomorrow then check again to see if they come back up but these were the codes:

7 TNA (Engine RPM) Signal
14 Road Speed Signal At CIS-E Control Unit
18 Current To Idle Speed Air Valve
27 Data Exchange Fault Between CIS-E Control Unit and EZL ignition Control Unit

I'm guessing 18 is from when I disconnected the idle speed air valve but don't really know too much as to what the other three codes mean. Any ideas?

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.