"Ask Me Anything " 10 Responses To Your Questions About Audi G28

How to replace audi key fob an Audi G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located near By the edges of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through a grey wire. The ECU utilizes this information to regulate fuel and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors accordingly.

If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating the chain is stretched or a jump link on the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).

Testing can be a bit difficult as there are two different connector pins, and they perform different functions but the most effective way to test it is to measure the resistance between the sensor and the ECU. When the sensor is fully functional, it should read about 1000 ohms. If you're experiencing issues with this sensor, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had a big cut in power as if the engine was running out of gas or the injectors are not firing at all. This morning i pull out the spark plugs. Three were drenched in gazoline, the fourth one was dry. When I start the engine, there are no sparks, i place a tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th stays closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero ohm. I think the issue is in another location.

I also tried to reset the PID without success. The car will start when the G28 is disconnected and runs fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.

I'm not certain what to do, but i feel i have pretty much eliminated everything else. However, i'm afraid that I may have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

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

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must be aware of the speed and position of the crankshaft to determine fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these sensors, the diagnostic scanner will display codes that could cause an engine shut down.

A failing G28 sensor could result in an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, or a misfire in the gear. It is possible that the sensor is failing and requires to be replaced if you notice any of these symptoms. The good thing is that they are very affordable and readily available particularly in the case of an Bosch model, like ours. You can also choose the GM version of this component is also a good option.

5. Tachometer

A failing engine sensor could cause a number of problems within your vehicle. It is a crucial part of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is rotating. If the sensor fails, it will disrupt the performance of the transmission and the other car's components.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends an electrical signal through gray wire to ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms resistance between those points. This is a common part across the audi lost key 80, 100, 200, near By UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.