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Ross
Ross, Diagnostic and repair technician
Category: Audi
Satisfied Customers: 1183
Experience:  Licensed diagnostic and repair technician
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My 2009 audi s3 automatic has problems reversing sometimes

Customer Question

Hi
My 2009 audi s3 automatic has problems reversing sometimes it goes into reverse but the car physically doesnt reverse sometimes usually when it is warmed up. When this happens the P on the dash starts to flash and the other gears flash and then decides not to drive in any gear till you turn the car off and back on again. Also sometimes when i come to a stop to 1st gear it gives a clunk sound to the gearbox and clunk sound when put into park
Submitted: 2 years ago.
Category: Audi
Expert:  Ross replied 2 years ago.
Hi my name is***** am a diagnostic technician and look forward to working with you.This sounds like the transmission range switch, also known as the Selector position sensor, this detects what position the selector is moved to, although it physically changes the gear selection inside the box, the gearbox may be set to Reverse for example, but the sensor is still saying its in Drive, this will cause confusion between the gearbox and ECU that controls it. the Flashing "P" Symbol is telling you the ECU has detected something is wrong, and the clunk into gears is because the ECU cannot control the gearbox to prevent the clunk without knowing the selector position. A diagnostic scan is a vital next step to confirm the fault, it will give a code and fault description e.g "Selector position switch - Range/performance" This would then pinpoint the exact fault so the sensor can be replaced. Any good garage can do this and usually costs around £40.This is almost certainly not a mechanical fault, although there is always a possibility something else such as a solenoid is failing which can cause similar problems so it is very important to have the fault code scan carried out first.
Expert:  Ross replied 2 years ago.
I hope I’ve provided the information you were seeking. If you need more help, please use the reply tab to continue our conversation. If you do not require further assistance, kindly rate my service. Thank you, Ross.