How to Replace an audi tt key fob G28 Engine Speed Sensor

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, directly above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know 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 the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched 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 since there are different connector pins, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read around 1000 ohms. If you're experiencing issues with this component, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors aren't firing at all. In the morning, i removed the spark plugs. Three were soaked with gazoline and the fourth was dry. I put tissue over each hole in the injector and when I start the engine without sparks, the three with gazoline jump out. The fourth one remains closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. I think the issue is in another location.

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 connected but it 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. Also, i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, i feel i have pretty much eliminated everything else. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or from 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 side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that must know the position and speed of the crankshaft in order to make decisions about fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner that could cause engine shut down.

Some of the signs of a failing G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. If you experience any of these problems, it is likely your sensor is deteriorating and should be replaced. They're cheap and easy to find particularly when they're an Bosch unit like ours. Alternatively, the GM version of this part is also a great option.

5. Tachometer

A failing engine speed sensor could be the cause of many issues in your vehicle. It is an important part of the transmission in your audi car key replacement because it relays information to the ECU regarding how fast or slow the engine is spinning. When this sensor fails, it will disrupt the performance of the transmission as well as the other car key replacement audi's components.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate fuel, timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can 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 as well as pin T26a/12. It should show around 1000 ohms of resistance between those points. This is a typical component across the audi etron key keys replacement cost (historydb.date) 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.