Audi Q7 no start

There are many reasons for audi Q7 no start. From those all the reasons some reasons behind audi Q7 no start are given below.

  1. Faulty battery.
  2. Blown fuse or faulty relay.
  3. Damage wiring harness.
  4. Faulty sensor.
  5. Faulty engine control module.
  6. Low pressure in fuel sypply system.
  7. Mechanincal failure inside engine.

Faulty battery :

If there is no light on cluster meter when ignition key is turn ON. Check battery terminal if connected or not. If battery terminal is propper connected that check battey voltage with the help of multimeter. There should be 12V at battery if it is less than that than go replace battery with new fully charge battery. Now check if cluster meter turn ON when ignition key is turn ON. If it cluster meter turn On than it means that there is no more battery problem.

Blown fuse or faulty relay is also a reason for Audi Q7 no start:

If battery voltage is proper and than still there is no ignition when ignition key turn ON. Than go to check fuse at fuse box , check fuse if there is any fuse is blown which is not letting the ignition turn ON replace that fuse or relay.

Damage wiring harness : When fuse and relay are good and there is no fault and ignition is not turn ON. Than there might be the problem of damage wiring harness in vehicle. Find that damage wiring harness in vehicle which is responsible for ON ignition in the system and repair it. After repairing damage wiring harness check starting system of vehicle. Try to crank engine by turning key, when ignition key is turn ON to start engine engine should start cranking. If it is not cranking than check power supply at starter motor there should be a 12V continue on starter motor. Another 12V will come there when key will turn ON to crank engine. If voltage is proper than check starter motor, repair faulty starter motor.

Faulty sensor due to which Audi Q7 no start:

There are many sensor at engine to sens different signals and send them to egine control module to start engine. When key turn to start engine,like Crank sensor, Cam sensor, rail pressure sensor, DRV valve etc. These are the main important sensor in vehicle which is responsible to start engine. If any one from these sensor will not send signal to engine control module than engine will not start. Like those all things there are many other things which are involve in this system to start engine in new coming vehicle. Check all of them properly to find out the reason behind no crank no start and according to them solve that problem.

Faulty engine control module:

Engine control module is use to monitor different signal from different sensor and according to them engine control module drive engine. When engine control module stop working due any reason like low power supply, damage wiring harness, blown fuse etc. Check all them properly, when found any one faulty from all of them do repair or replace so that engine control module start working properly. When all the other things is good and there is no problem. Than check problem at engine control module it self, it could be possible that engine control module is also faulty.

Low pressure in fuel supply system:

While cranking engine there should be require amount of fuel pressure to start engine. If there will be no pressure of fuel at engine while cranking than engine will not start. Low pressure fault in vehicle could be seen due to multiple reasons like faulty low fuel pressure sensor, failure of high pressure fuel pump, leak fuel pipe line, block fuel filter, faulty rail pressure sensor, failure of any one or more injector. If you want to find problem actual problem behind low fuel pressure in the system you need to check all these parts one by one.

Hook up scan tool to find out fault code. It will make easy to you to find out pressure of fuel from high pressure fuel pump. Check actual and require pressure of fuel according to the manufacturer if is equal or not. If fuel pressure doen not match the require fuel pressure than it is confirm that there is a problem of low fuel pressure.

Mechanincal failure inside engine:

When there will be any mechanical fault inside engine than also there will be the problem of no start. Like problem inside engine head block, as it work as opening and closing of valve. There are two cam shaft inside engine head block, if there will be any damage on the edge of cam shaft from where cam shaft sensor monitore the rotation of engine and this signal to engine control module. Than also engine will not start due to wrong signal from cam shaft sensor.

At the lower parts of engien there are four pistion, which are connected with crankshaft. If there will be any problem detected like worn out pistion, broken piston than also there will be problem of no start. At crank shaft there will be a ring from where crank sensor monitor speed of engine revolution. If due to any reason that ring will breakdown than crankshaft sensor will not be able to sense speed of engine revolution. Due to this reason also engine will not start. Because engine control module will not fire fuel into combustion engine. Like this there would be many problem can be find inside engine when engine does not start.

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