The 10 Most Scariest Things About Audi G28

How to Replace an audi tt key fob not working G28 Engine Speed Sensor

Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located near the edges of the transmission, above the flywheel ring gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through an uncolored wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors in the right way.

If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).

It's a bit tricky to test as there are various pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is operating at its maximum. Examine replacement key for audi evidence of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, i experienced massive power loss like the engine is out of gas or injectors aren't firing at all. I pulled out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th one stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. So i assume the problem is in another place.

I also tried to reset the PID but without success. The car can start if the G28 is not plugged in and is running fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c, even if I unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do. I feel like i've pretty much ruled everything else out. But i'm worried that I might have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, audi lost key ABY and ADU) engines have an ECU that has to know the speed and position of the crankshaft to make decisions about timing of the fuel injectors, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will show the codes that could trigger an engine shutdown.

The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or a misfire when you're in gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these signs. The good news is that they are quite affordable and readily available particularly in the case of an Bosch sensor, like ours. You can also choose the GM version of this part is also a good choice.

5. Tachometer

A faulty engine speed sensor could be the cause of many problems in your car. It's an essential component of the transmission of your Audi tt replacement key since it sends information to the ECU about how fast or slow the engine is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.

The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between these two points. This is a common part across the audi keys replacement 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.