Ignition Coil 1 (1271) - What's next?

[mike.bmw]

My check engine light has not been on, but I decided to perform a stomp test in an effort to diagnose a separate issue (thermostat stuck open). I was surprised to see the stomp test revealed code 1271: Ignition Coil 1.

The car has been running smoothly. No noticeably misfires at any RPM. Aside from my coolant temps being lower than normal (likely due to thermostat stuck open) the car has been running well. 137K miles. Within the last 1,000 miles I've replaced the mess under the intake with all OEM parts (hoses, clamps, gaskets, injectors).

To further diagnose the issue I have done the following:

- I swapped plug wire 1 and 3. Reset codes. Verified codes cleared. Started engine. Stopped engine. Checked codes again to reveal 1271.
- I swapped spark plugs. Reset codes. Verified codes cleared. Started engine. Stopped engine. Checked codes again to reveal 1271.
- I swapped coil 1 and 2. Reset codes. Verified codes cleared. Started engine. Stopped engine. Checked codes again to reveal 1271.
- The plugs all look normal.

Any ideas what could be causing this code every time I start the car? Based on the tests above, I would've expected the code to change to a different coil/cylinder based on swapping plug wires, plugs, and coils. That had no effect and it was coil 1 each time.

[1998ccc]

Coil driver??  Have a spare DME?

[mike.bmw]

Coil driver??  Have a spare DME?

I'm looking into buying a spare DME/ECU now.

[DesktopDave]

Sounds like a coil driver to me too. I have two to three DMEs with burned-out coil drivers. It could also be a bad plug or wiring harness since it won't move from #1. Did you do a continuity or resistance check on the DME plug to coil pack wires? I have a diagram around somewhere...be sure to unplug the DME first!

I have a good spare E30 DME.