Audi G28: The Good The Bad And The Ugly

How to Replace an audi advance key G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors in the right way.

If this sensor fails when it fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jump in the chain link of the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).

It is a little tricky to test because there are different pins on the connector, and each one has different 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 it is in full operation. Look for signs of coolant, or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a massive decrease in power. It was like the engine had run out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs. Three were drenched in gazoline, the 4th one was dry. When I crank the engine with no sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stay shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. So i assume the problem is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.

I don't know what to do. I think I've all other possibilities out. But i'm worried that I might have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or a parts store. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They should be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and audi Key fob replacement cost ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, for example. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal, and/or a misfire when you're in gear. If you have any of these issues it is likely your sensor is going bad and requires replacement audi key fob. They are cheap and easy-to-find particularly if they're a Bosch unit like ours. Alternatively, GM's version of this part would be an option.

5. Tachometer

A damaged engine sensor could cause a number of problems in your car. It's an essential component of your audi keys replacement cost's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to fail and other car components to be affected.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This is a typical part that is found across the audi key fob replacement cost 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.