Questions and Answers

BMW 328i DTCs E5, E9 And EF Q. Hi Vince, You've helped me once before with my BMW, now I have another problem. My car is 1998 BMW 328i manual transmission, 65,000 miles. My Check Engine Light is on, and engine runs rough when cold. After five minutes engine is stable. I scanned it with Peake scanner and the codes were E9, E5, and EF.

I looked at the code chart that was sent along with the scanner for the three codes.

• E5 - O2 Sensor Pre Cat, Bank 1, Slow Response Time.
• E9 - Catalyst Efficiency Below Threshold Bank 1.
• EF - Cylinder 2 Misfire Detected.

Well, that left me clueless. When I replaced the spark plugs last week, it didn't make any deference. If it was ignition coil it should register a code. I checked all the coils for damage or broken boots in the end of the coil, they all looked good. So what do you think the problem is?

Also when I put the defogger I smell antifreeze and it goes away after one minute. Do you think something wrong with the heater core? Sorry I am asking to many questions, and thanks again for your help.

Rafael
Seattle, WA

A. I think the E5 and E9 codes are the result of the EF code. So we have to take care of EF before looking at the other two.

The E codes are generally less specific than the P codes. They may tell you "Cylinder 2 Mis-fire" and that's it where a P code will tell you, for example, Ignition Coil 2 Low Voltage. If yo have good spark at the number two spark plug, and the spark plug itself is good, then we have to look at the injector.

To check the injector you can get a "Noid Light" at a parts store. Unplug the injector connector and plug the niod light into the injector connector. Start the engine. If it flashes while the engine is running, then the injector electrical system is working and the injector is bad. If it stays on steady, you have an open in the wire between the injector and the PCM or a bad PCM.

The anti-freeze smell could very well be the first signs of a heater core leak.