Map code - BMW Forum

fastshivy · 10-30-2007, 07:33 PM

My 1999 540 keeps setting an ses light. I pull the codes and it comes up as a map circuit board. I am assuming this is manifold absolute pressure. Does anyone have any ideas as to what could be causing this? Hose leaks? Any ideas? Just a bad circuit? Thanks for any help?

benzin · 10-31-2007, 10:00 PM

most likely you need to replace the map sensor.That would be located in the intake manafold.

fastshivy · 11-01-2007, 05:07 PM

The code according to Peake is.... Map controlled thermostat circuit/control. I am not sure this car has a map sensor. Could this be something more related to climate control?

Dirty_Tool · 11-01-2007, 10:02 PM

BMW does not use MAP sensors.
its for the engine coolant thermostat, om this car it is electronically controlled, thats why it can set an SES lamp.
Most likely just needs a new thermostat.

fastshivy · 11-02-2007, 06:44 AM

Thanks DT-- The thermostat and water pump were replaced about 1 year ago. I also replaced the radiator and used genuine BMW coolant.The coolant I replaced looked perfect no rust etc. I have never had an issue with overheating etc. It also sets a code for safety concept monitoring....are the two tied together? Thanks again for getting me on the right path

fastshivy · 11-07-2007, 01:13 PM

Well, now I am getting a consistent knock sensor code on cylinder 3-4 I have not replaced the thermostat yet, so the code comes on the same time as the MAP code. I clear them and they are back on in about 5 miles. Are these related? Does the intake manifold have to come off to reach the knock sensor?

fastshivy · 11-08-2007, 03:56 PM

un be friggin believable I pulled the intake manifold today and a rat or some kind of varmit had crawled under my intake. The knock sensor wire was chewed in half and there was nesting material every where! This car gets driven almost daily so that must be one mean critter. Replaced the electronic thermostat as well. Bimmer forum had a good explanation as to how they work. Makes sense now. Well I hope the bastard freezes tonight!!!!!!!!!!!

Dirty_Tool · 11-13-2007, 01:25 AM

damned Rats... I see a lot of rat damage on wires, BMW must dip their wiring harnesses in syrup before installing

fastshivy · 11-13-2007, 12:00 PM

Ha Ha that is funny. I just put it back together and it runs great, no more codes! Coated the wires with arsenic and peanut butter..Ha ha