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Christopher
Christopher, Technician
Category: Audi
Satisfied Customers: 438
Experience:  VW certified technician, VAG enthusiast
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2003 Audi A4: light comes..the car will stall at stop lights..restart

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Hi, My 2003 Audi A4 1.8T has a problem. The EPC light comes on and the car will stall at stop lights. It will usually restart but once had to wait about 5 hours for it to start again. When this happened, I could not here the fuel pump when turning key on like usual. Pump was replaced 3 months ago. It also seems like there is no cooling fan at radiator even though temp gauge reads normal range. The fan do come with a/c for sure! Any help would be greatly appreaciated. Thanks, Steve

Hello,

The Fuel pump could be a culprit, but i would like to know what fault codes are stored causing the EPC light to turn on.

EPC light will also turn on when the mass air flow sensor is failing, also causing the engine to stall out.

If you take the car to an Autozone or Advanced Auto/Kragen they will be able to scan your fault codes for free, Write the fault code numbers down (ex. p0301)

This will be the best bit of information to help you resolve this issue with your car!

Customer: replied 9 years ago.
Reply to Christopher's Post: Hi Christopher,
I have a cheap scan reader that pulled a code.
The code is for the crank/engine speed sensor not recieving a signal. It gave a P0322 (pd) code and read "Crankshaft/Engine Speed (RPM) Sensor - No Signal" Does that help?
Thanks, Steve

Yes, Excellent!

Your engine speed sensor is faulty.

If you would like a procedure on how to test it or a explaination of how to replace it let me know i can provide you with this information.

Customer: replied 9 years ago.
Reply to Christopher's Post: While waiting for first reply I was letting car run to see if the cooling fan would turn on. It came on as gauge was barely past mid-range and seemed to work ok as it went off as gauge went just below mid-range. My concern is, it seems like it use to come on whenever engine was running. Is that just my imagination? Also after I let car warm up to verify fan coming on, I shut it off and when I tried to restart it, it will not fire. Has happened last weekend like this also. It would not restart for about 5 hours until it had cooled down. Any ideas? Would the speed sensor cause this to happen?
Thanks
Customer: replied 9 years ago.
Also Christopher,
I would appreciate whatever info you could give me on Diagnosing/Replacing sensor.
Thanks for all of help!

No the speed sensor would not cause any issue's with your cooling fans.

You should have 2 Cooling fans.

One that runs whenever the engine is running and your auxiliary fan, which operates when the AC is on or the engine is getting hot.

The Auxiliary fan will cycle on and off, if i recall correctly it will turn on in 15 second spurts.

If the engine is not overheating i would not be concerned with the fan operation.

Customer: replied 9 years ago.
Hey, one more thought.
Is it possible that the problem could be heat related? It does not happen until car is warmed up for a few miles. Once temp gauge hits mid-range, rpm gauge starts to drop below 1000 rpm's and soon after car starts to stall at stops.
Thankss again!
Customer: replied 9 years ago.
Hi Christopher,
I was not sure if you saw my request for info on check/replacing speed sensor. I would like to recieve that if possible.
Thanks for everything, Steve

It could be, but nothing that is not normal.

When engine speed sensors start to fail they will stall the engine out randomly, ex. when the engine is warm when the engine is cold, when the car is moving, when its idling, its hard to say because the engine speed sensor is so critical to the engine's ability to run when it has a glitch in the sensor the engine will stall out.

If you would like the information on how to check this sensor to make sure 100% it has failed and the root of your issue i will provide you with this information, but i am about 98% sure this is the reason your engine is stalling out.

Was the engine overheating? (This will be a seperate issue)

Customer: replied 9 years ago.
Christopher,
I don't see the engine overheating at the gauge, but it does seem to be quite warm. I live in Hawaii and it is always HOT! I definately have no fan running while engine is running until it starts to go past middle range on dash gauge or I turn on the A/C. The fan that does come when engine gets warm is the opposite one from the A/C. That tells me both fans are OK. Does that mean a sensor problem? Is there more than one sensor for the fan circuits? It also seems like the fan would come on after driving sometimes and that does not happen anymore.

Before performing test, make sure that sensor is correctly installed and firmly seated

Disconnect Engine speed (RPM) sensor connector -G28--3-.

graphic

To gain access to the connector, remove coolant expansion tank bolt (arrow) and move expansion tank to the side. Fuel hoses remain connected.

graphic

Connect multimeter between terminals 2 and 3 to measure resistance

graphic

Specified value: 730...1000 Ω

The resistance value of the Engine speed (RPM) sensor -G28- is associated with a temperature of 20° C. The resistance increases if the temperature increases

If specified value is not obtained:

Install new Engine speed (RPM) sensor -G28-.

If specified value is obtained:

Connect multimeter between terminals 2 and 1 -screen- and 3 and 1 -screen- to measure resistance

Specified value: each case ∞ Ω (no continuity)

If specified value is not obtained:

Install a new Engine speed (RPM) sensor -G28-.

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