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

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer on 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 an electrical signal to ECU pin T55/49 using a grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC and also where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain stretching or a jump link on the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).

It can be a bit difficult to test as there are different connector pins, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is in full operation. If you're experiencing issues with this part, check for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge decrease in power. It was like the engine was running out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. I put a piece of tissue over each injector hole, and when I start the engine without sparks, the three with gazoline jump right out. The 4th one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming that the issue is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However, the intermittent misfire problem continues to occur 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 oil gauge in the cockpit shows 2 bar when the actual pressure is zero.

I'm not certain what to do, i think i've pretty much completely ruled out all other possibilities. But i'm worried that I may have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style sensor 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 junkyard or at a parts store. It is simple to test them by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They should 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 regarding fuel injector timing etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, the diagnostic scanner will display codes that could lead to an engine shutdown.

Some of the signs of a failed G28 sensor include an inaccurate rev counter replacement key for audi a4 the gearbox the gears are shifting faster than normal and/or a misfire when you're in gear. If you are experiencing any of these issues, it is likely your sensor is going bad and needs replacing. They're cheap and easy to find, especially when they're a Bosch sensor like ours. You can also choose the GM version of this component is also a good choice.

5. Tachometer

A failing engine speed sensor could be the reason behind a slew of problems in your vehicle. It's a vital component of your audi spare key cost's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. This sensor can cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those points. This is the same across the audi tt key 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.