How to Replace an new audi key G28 Engine Speed Sensor

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

1. Engine Speed Sensor

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

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.

If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test as 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 about 1000 ohms if the sensor is at full operation. If you're having issues with this component, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or injectors aren't firing anymore. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I placed a tissue over each injector hole and when I start the engine without sparks, the ones with gazoline jump right out. The 4th one remains closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero ohm. I'm assuming the issue is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I don't know what to do. I think I've all other possibilities out. I'm afraid i may have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or parts store. It is easy to test them - just switch your DMM into resistance mode and measure 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 know the position and speed of the crankshaft in order to make decisions regarding timing of the fuel injector, audi Replacement key service for example. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause an engine shutdown.

Some of the symptoms of a malfunctioning G28 sensor include an inaccurate gearbox rev counter the gears are shifting 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 experience any of these symptoms. The good news is they are very affordable and readily available, especially when you're looking at the Bosch unit which is what we have. You can also choose the GM version of this unit is also a good option.

5. Tachometer

A failing engine sensor could cause a variety of issues in your car. It is an important part of the transmission in your Audi Replacement Key Service since it sends information to the ECU on how fast or slowly the car's engine is turning. This sensor can cause the transmission to malfunction and other components in the car to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also verify continuity between pin 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. You should detect an average resistance of 1000 ohms in these areas. This is a typical part that is found across the audi tt key replacement 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.