4f81 EGS:Ratio monitoring clutch A

In BMW E-series E70,E80,E90, fault code 4f81 EGS:Ratio monitoring,clutch A is related to the problem with automatic transmission gear box. BMW use 5speed or 6speed automatic transmission gear to make a comfort driving. whenever problem occurs in gear shifting this kind of fault code store in automatic transmission control module. this type of problem can be caused either by faulty transmission mechatronic solenoids or internal clutch wear. Worn out multiclutch can lead to no shift of gear after 3rd or 4th gear.

When this type of fault code store control module, it means that Clutch A is not working. When clutch A will stop working than there will be the problem of gear shifting in automatic transmission. It can be possible that there could be no gear shifiting after starting vehicle. when you will try to accelerate the engine to move vehicle in forward position than also there will be not movement in vehicle. But if in case vehicle is moving and running properly than you might be face problem at high speed. As clutch A is not resposible for shifting all the gear’s due to which problem can be seen at high speed.

Most of the time this kind of problem occurs while driving at high speed. while driving at low speed you feel no problem at all. but after certain kilometer at high high speed you feel jerking in the gear box. there will be no gear shift after 3 gear, but you will notice high rev at cluster. gear will stuck at 3rd gear position, there will be no changes in that either up or down. transmission will be lock at 3rd gear position without going up or down. Then pop up of warning light will appear on cluster or navigation screen. but if you will turn off the car for some time and wait. then again if you will start the vehicle everything will be fine as it was before.

Symptoms of 4F81 EGS:Ratio monitoring:clutch A:

  • Gear box malfunction will illuminate on cluster meter.
  • Vehicle may not shift gear.
  • Fault code may store in engine control module.
  • If vehicle will move than problem can be seen at high speed.

Causes of 4F81 EGS:Ratio monitoring:clutch A:

  • Faulty mechatronic inside automatic transmission.
  • Faulty mechatronic solenoid valves.
  • Worn out multi clutch.
  • Reprograming of gear box.
  • Low transmission oil level.
  • Electrical problem out of the gear box.
  • Mechanical problem inside gearbox.

How to trouble shoot:

There might be to many different causes behind this problem.

STEP#1: Check the oil level in automatic transmission gear box for its require level and also quality of oil. Check the driven kilometer if it is above 60-80K kilometer it is require to change. As most of the automatic transmission making company give advice to change the transmission oil after 60-80K kilometer. Check the quality of oil if it is require then change the oil with the manufacturer recommended transmission oil. After changing oil perform adaptation of gear with the help of BMW ISTA software that might be solve the problem.

STEP#2: This can be happen because of some electrical problem in the automatic transmission or out of the automatic transmission. Like at control module or in the wiring harness. Check the problem out of the gear box, if found damagw wiring harness or any faulty fuse or relay then repair or replace that and than solve it. Which will help you to solve the problem quickly, but if it is inside the gear box. It might let you to do hard wok with gear box to solve the problem.

STEP#3: The problem can be inside the gear box, either faulty mechatronic solenoid, worn out clutch or faulty multiclutch. If anyone of these things are not good it will cost to much to repair as all parts of gear are costly to repair. Replacing of transmission gear box with the use gear box is better than repairing or replacing the mechatronic solenoid, worn out clutch, faulty multiclutch. Change the gear box unit as well as flush the transmission oil, change transmission oil and oil filter. Perform adaptation of gear box after changing the gear, it will calibrate its clutch accordingly.

How risky it is drive with fault code 4F81 :

Driving with the fault code 4F81 is not highly risky as it will only not allow to change the gear after 3rd or 4th. Gear will be lock after 3rd or 4th gear it will not move either up or down. At low speed no problem can be found but after a certain kilometer driving at high speed jerking will feel in the gear box. That’s why it will only stop you to drive at high speed.

Solution:

  • Replace faulty mechatronic solenoids.
  • Repair mechanical problem in gear box.
  • Replace worn out multiclutch.
  • Change oil of transmission at certain kilometer.
  • Repair electrical fault if any.
  • Reprogram automatic transmission.

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