1994 Mercedes-Benz C 180 (W202) won't start

Question

Background

My 1994 Mercedes-Benz C 180 (W202) won't start.

We are in a very cold winter, but even one month ago, it was not that cold.

Under the rear view mirror, there are two small lights: one is blue, the other is red. They start blinking red and blue simultaneously whenever:

• I turn the key on when starting the car.
• I press the IR remote to lock or to unlock the doors.

What Happens

Main Issue

1. A couple of days ago, the car did not start.
2. After waiting 24 hours (in the same cold), it started.
3. For the next 6 hours, it was fine.
4. 9 hours after that, it wouldn't start.
   • It had a brand new car battery.
   • The starter cranked, but it was not enough to start the car.
   • The battery light came on after turning the key.
   • When using the IR remote, the lights weren't blinking.
   • The dash lights were ok.
   • I can hear the fuel pump go "ZZZzzz" which sounds normal.

Possibly Related Issue

Sometimes, pressing the IR key won't open the car doors. The car does not respond to the IR remote no matter how close I am to it.

When the IR remote does work, it only works if I am very close to the side mirror.

What I've Tried

• I had the car battery changed one day ago.
• The IR key's lithium battery was changed 2 months ago.
• I checked for corrosion on the battery connectors. They are holding well and don't have any rust.

Questions

Follow-up 1

• I have just sent the car to a mechanic, No Fuel pump problem, the problem is only electrical. More checking will be done later.

Follow-up 2

• CRANKSHAFT CRANK ANGLE SENSOR defection ,not sure yet as we still cannot find it for this module..

Follow-up 3

• the condition is more serious.
• The mechanic was getting to the conclusion that there is a faulty electric problem related to the security system.
  • He was suggesting for me to use another key. Unfortunately i don't have another one.
• that mechanic told me he cannot assess/correct the problem any further.
• A certified mechanic/house,that looks for similar issues, told me through the phone that what my mechanic is fearing could get easily costing as much as 1000 Euro without labor. I can get with that price an identical non-faulty car in the market.
• At this stage the care have to be treated like a waste, as there is not much alternative for leaving it somewhere else. Furthermore my mechanic is asking for removing the car from his property as soon as possible.

Follow-up 4 and Conclusion

• There was too many call to drag the car from the front of the store of the mechanic. There was a chaotic snowing days. Also removing the car cost something like 100-150 euro. There was no affordable alternative to even mess with that system, my only excuse here is my own ignorance! The hint of Cc Dd below could have given me an opportunity. Now is too late, as i have handed the car over to recycling services.
• sadly the car has been driven only for 207 thousand and still very clean.
• I believe that a small and basic knowledge if how cars function could save us a lot of troubles.
• Thank you all for your support. This was an opportunity to learn.

Game Over.

Answer 1

some stuff to check:

• is your alternator giving enough power? use a voltmeter when the car is running and touch the leads to the pos and neg terminals of the battery it should read at a minimum 13.5 and a maximum of 14.75 Volts. if it is less than the battery is probably not getting enough charge while driving.
• did it work fine the first few times after you swapped the battery? if so then it is even more likely it's an alternator issue
• is the battery's ground cable connected well to either the frame or the engine block
• is the engine block ground cable connected well
• are the headlights dim at all? if they are this could be low power and explain the door locks not working well.
• check the battery with the voltmeter when it is not running. it should read between 12 or more volts. If it is less it is not being charged enough. Typically batteries sit at around 12.2V but with the cold it may be a little less. The car probably will still crank at 11.5 but that is pretty low.
• It could be your starter. either the grease is gummed up from the cold which can prevent the brushes from contacting the commutator or there could be a different issue with the starter. If you can get to it try tapping it and see if that gets the car to start
• Check the cable going to the starter this may be loose or frayed.
• lastly wrap your engine in a couple moving blankets and see if this changes the no start issue. It could be some part is just too cold.

There is more things that can be checked but these are the most likely

due to the door and IR remote I am highly suspicious of your alternator. But these could be unrelated.

I would also be cautious of tracing sensor faults if the engine was cranking slowly and if the alternator is not working well. having low power on those sensors and computer can cause false readings. Also the crank position sensor is probably not going to cause a slow cranking condition as you stated happened.

also I would not rely on thrown codes. If it is a low power issue fix that first and reset the computer drive it around through its drive cycle and see if there are any new issues. If not great if there are then tackle those when they show up.