Skip the auto shop - Our mechanics make house calls

Q: My Audi revs but will not drive in reverse. The ABS light is on and the brake light flashes on the dash. What could be the cause?

asked by on

Audi revs but will not drive in reverse...ABS light is on & Brake light flashes on the dash. What do you think I need?

My car has 120000 miles.
My car has an automatic transmission.

A: The transmission needs around 100 psi press...

The transmission needs around 100 psi pressure to operate all of the forward gears, but it needs 180-190 psi pressure for the reverse gears.

The transmission pump is designed to create 1000 psi of pressure and it is regulated by a pressure regulator located next to the pump. Check the wiring harness to the transmission and check the pressure to the transmission pump through the cooler lines. If the pressure is about 30 psi to 45 psi on the cooler lines and the wiring harness is in good condition, then the pump and the regulator is working correctly. In that case, the problem would now be within the transmission valve body (control module).

If the pressure is higher than 45 psi on the cooler lines, replace the pressure regulator solenoid in the transmission. If you need assistance, get a certified professional, such as one from YourMechanic, to replace the transmission oil pressure switch for your vehicle.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: I'm replacing the wiper motor/pulse board assembly.

Hello - yes, it is possible that you have locked down a pivot point or other piece of the linkage that is meant to turn or rotate. Try loosening pivot point nuts/bolts, and retry the motor. Unfortunately, this is one...

Q: Convertible lever broke

Hello. The convertible top is controlled by the electrical rocker switch in your console. The reasons for the top not operating could be that the switch is bad, or there is a fault present in the convertible top control unit....

Q: Car overheating and squealing.

Overheating can be caused by a number of things. Usually when you start noticing the temperature go up it is because there is not enough coolant in the system to cool the engine down. As the temperature goes up, much...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...