How to Replace an audi remote key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49) and then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

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

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft reached TDC, and the location of the camshaft so that it can activate the spark and injectors.

If this sensor fails, the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync and 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).

It's a bit tricky to test because there are various pins on the connector, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms if the sensor is operating at its maximum. Look for signs 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 had massive power loss like the engine is out of gas or the injectors are not firing at all. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the fourth one was dry. When I crank the engine, there are no sparks, I put a piece of tissue on the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. So i assume the problem is in another place.

I also tried to reset the PID but without success. The car is able to start if the G28 is disconnected and is running fine when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I'm not sure what to do. I believe that I've all other possibilities out. However, i'm afraid that I might have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sender is identical to the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. It is simple to test them - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft in order to make decisions about timing of the fuel injector, for example. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these, the diagnostic scanner will display codes that could cause the engine shutting down.

Some of the signs of a malfunctioning G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal, and/or a misfire when in gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these symptoms. They're cheap and easy to find especially if they're a Bosch model like ours. You can also choose the GM version of this component is also a good choice.

5. Tachometer

A damaged engine sensor could cause a myriad of issues in your car. It is a crucial part of your audi keyfob's transmission, since it relays information to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it will affect the performance of the transmission as well as the other car's components.

The G5 engine speed sensor is situated on the outside 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 control the flow of fuel and boost and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can check the sensor for audi remote key failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms in these areas. This part is common across the audi tt key programming 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du So, you may find them in wrecking yards.