This might be a long shot, but does anyone know what the logic is for triggering the different Check Engine Light (CEL) errors is? I've always wondered this, but can't find the info.
An example would be this:
Stomp test reveals code 1223, Coolant temperature sensor.
This sensor relies on the temp sensor causing a change in resistance, which the ECU can detect. Here are a few different logical scenarios that could be interpreted as a failure.
Any combination of the above, or something I can't imagine, could be what BMW chose to trigger the CEL, but that info isn't in the Bentley or manual. Does anyone have that in their treasure trove of knowledge? I wouldn't mind having the info for all the CEL codes if at all possible :)
Cheers,
Tyler
An example would be this:
Stomp test reveals code 1223, Coolant temperature sensor.
This sensor relies on the temp sensor causing a change in resistance, which the ECU can detect. Here are a few different logical scenarios that could be interpreted as a failure.
- The resistance is outside the expected range. Say 100,000 ohms.
- The resistance changes too rapidly. BMW had a pretty good idea how long it would take these engines to warm up, and they could say "If the engine is running, and the temperature has only risen 10 degrees in 10 minutes, the sensor is broken"
- If the resistance ever rises, and then falls, and then rises again before reaching operating temp.
- In combination with any of the above, they could have a time association where it has to be in a failed state for longer than X amount of time.
Any combination of the above, or something I can't imagine, could be what BMW chose to trigger the CEL, but that info isn't in the Bentley or manual. Does anyone have that in their treasure trove of knowledge? I wouldn't mind having the info for all the CEL codes if at all possible :)
Cheers,
Tyler