421474 output speed and wheel speed

Fault code 421474 Output speed and wheel speed: impermissible deviation is related to the problem with failure of DSC (dynamic stability control) control module in BMW. DSC control module is use in vehicle for the braking purpose. Vehicle automatic transmission recieve signal from DSC control module to gears accordingly. In automatic transmission there is also a vehicle speed sensor build in which is use to sens vehicle speed and this signal is also use by automatic transmission control module to shift gear. Automatic transmission control module use signal from both wheel speed sensor through DSC (dynamic stability control) control module and also from vehicle speed sensor and use these signal to shift gear according to speed of vehicle. when transmission control module recieve wrong signal from any one from these two than it store fault code 421474 Output speed and wheel speed: impermissible deviation.

Causes of 421474 Output speed and wheel speed :

  • Faulty any one or more wheel speed sensor.
  • Faulty vehicle speed sensor.
  • Damage wiring harness of ABS sensor.
  • Failure of DSC control module.
  • Faulty transmission control module.

Symptoms of 421474 Output speed and wheel speed :

  • DSC failure warning light will illuminate on cluster meter.
  • Loss of power while driving.
  • To speed up vehicle high acceleration require.
  • Warning light will illuminate on cluster meter while driving.

How to trouble shoot :

  • When you see warning light on cluster meter related to the problem of DSC failure. Stop vehicle as this warning light is indicating problem towards DSC control module which is a braking control module. To solve this kind of problem you need to scan vehicle with the help of scan tool and also it require expert technician to solve problem.
  • Scan vehicle with the help of scan too and when found fault code 421474 Output speed and wheel speed: impermissible deviation. Than with the help fo scan tool check all four wheel speed sensor reading. Take a test driving with hooking scan tool in vehicle and check all four wheel speed.
  • All four wheel reading should be same while driving vehicle. If found any one or more sensor reading signal is fluctuating than check that sensor. For example if fluctuating reading is from rear right side. Than you have to work on rear right side, first check voltage at the sensor socket when ignition is turned ON. There should be voltage at sensor socket because there is no any current fault in system thats why there should be voltage at sensor.
  • To confirm that if sensor is faulty or not swap left rear sensor the right rear sensor and than take a test drive and check reading of sensor. If the fluctuation shift to left from right than it means that there is problem of sensor. Replace faulty wheel speed sensor and again check reading of sensor there should be no fluctuation at reading right now.
  • If still fluctuation of sensor reading is coming from right side than it means that there is a problem of ABS reluctance. There is a reluctance installed in wheel also called as wheel bearing. Check that reluctance on which wheel speed sensor run, to check reluctance take vehicle on jack and remove tyre than remove wheel speed sensor. Now if vehicle is rear wheel drive than start vehicle and put it in Drive mode, than take a rust cleaner and start spraying at wheel reluctance which is rotating that will clean that reluctance if there will be any dust or any thing else which is creating problem.
  • If it does not work than it is possible that there might be the problem of that reluctance. There could be the problem of broken reluctance which is creating this problem. In this situation you need to change whole wheel bearing to clear out the problem.
  • But if still there is some fluctuation at sensor reading and the fault code is still present in control module. Than it means that there is some problem at DSC control unit. Check DSC control unit for water damage or any other issue with control module.
ABS connector
Abs control module

Solution :

  • Repair damage wiring harness.
  • Replace faulty Wheel speed sensor.
  • Replace faulty wheel bearing.
  • Repair or replace damage wiring harness.
  • Replace faulty DSC control module.
  • Repair or replace blown fuse.

Special note :

  • Before replacing DSC control module, check all the above trouble shoot procedure. In this situation ther might be the problem of somthing other like short CAN line wiring harness, faulty stearing control module which might be disturbing CAN line.

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