CD9451 massage signal invalid

Fault code CD9451 massage (vehicle speed46.1.2) signal invalid is related to the problem with DSC(dynamic stability control) module. When there is some problem occurred in dynamic stability control module. DSC control module send signal to other control module that there is some problem in dynamic stability control module. DSC(dynamic stability control) module control braking system of vehicle. There are four wheel speed sensor on each wheel. Who send signal to dynamic stability control module about wheel speed or vehicle speed. When there is any problem occurs at any one of those four wheel speed sensor. Like if any one wheel speed sensor stop sending signal to the DSC control module due any reason (faulty wheel speed sensor or damage wiring harness of the sensor). Than DSC control module store this fault code CD9451 massage (vehicle speed46.1.2) signal invalid in memory.

Transmission control module get signal from DSC control module of about all four wheel speed. According to wheel speed sensor signal transmission control module shift gears. When transmission control module recieve irregular signal from DSC(dynamic stability control) module. Than automatic transmission control module feel trouble to shift gear. Due to which vehicle will start jerking while driving because of late gear shifting.

Mostly this fault code store in Dynamic stability control module when control module do not recieve any signal from any two wheel speed sensor. When any two wheel speed sensor will stop working than DSC (Dynamic stability control) module will not receive any signal. Due to which control module store this touble code in control module.

Causes of CD9518 massage signal invalid :

  • Faulty wheel speed sensor.
  • Damage wiring harness of wheel speed sensor.
  • Faulty wheel bearing.
  • Faulty DSC (dynamic stability control module).
  • Water damage at connector of DSC (Dynamic stability control) module.
  • Failure of any other control module.
  • Damage CAN line wiring harness.

Symptoms of CD9518 massage signal invalid :

  • DSC warning light will illuminate on cluster meter.
  • Vehicle will start jerking while driving due to late gear shifting.
  • Fault code wil store in control module.
  • There will be some noise from brake when you will apply brake.

How to trouble shoot :

  • When there is warning light on cluster meter or center display related to the problem of DSC (dynamic stability control) failure. Stop vehicle as this warning light is indicating problem towards DSC(dynamic stability 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 tool, when found fault code CD9451 massage (vehicle speed46.1.2) signal invalid. Than with the help of 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 speed sensor 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 of sensor is from rear right side wheel. Than you have to work on rear right side wheel, 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. Voltage may come and go very quickly when ignition is turned ON. Check properly voltage at wheel speed sensor when ignition is turn ON. In some model voltage stay there but in some model voltage didn’t stay there.
  • To confirm that if sensor is faulty or not, swap left rear wheel speed sensor with the right rear wheel speed sensor. than take a test drive and check reading of sensor. If the fluctuation shift to left side from right side than it means that there is a 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 in sensor reading is coming from right side than it means that there is a problem of DSC(dynamic stability control) reluctance which is also known as wheel bearing. There is a reluctance installed in wheel. 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. But in some model vehicle there is no metal reluctance.
  • 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 (dynamic stability control) unit for water damage or any other issue with control module.
  • In bmw 5 series model vehicle DSC (dynamic stability control) module is use to place behind front left tyre under the left piller. When you remove fender liner than you can see pipe line of DSC (dynamic stability control) control module. Due to the location of DSC (dynamic stability control) control module water get enter in control module. Just because of which there is more chance of failing of DSC (dynamic stability control) control module.
  • When you remove socket of DSC (dynamic stability control) control module you will see water damage at connector of DSC (dynamic stability control) control module.

Solution :

  • Replace faulty wheel speed sensor.
  • Repair damage wiring harness of wheel speed sensor.
  • Replace faulty wheel bearing.
  • Replace faulty DSC (dynamic stability control) control module.
  • Repair damage wiring harness of DSC (dynamic stability control) sensor.

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