How to Replace an audi keys replacement G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated near 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 located in the instrument cluster.

1. Engine Speed Sensor

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

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC, and where the camshaft lies to trigger the spark and injectors.

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

It can be a bit difficult to test because there are various pins on the connector and each has its own functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. Look for signs of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a significant reduction in power. It was as if the engine was running out of gas. Or my injectors were not firing. This morning i pull out the spark plugs, three were drenched in gazoline, the fourth was dry. When I start the engine with no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stays shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I get 0ohm. I assume that the problem is somewhere else.

I also tried to reset 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 problem continues to occur at higher RPM. The temperature sensor key for audi the coolant (G62) shows the wrong temp value -49c even when i unplug it. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.

I’m not sure what to do. I feel like i’ve pretty much all other possibilities out. I’m concerned that i may have missed something. If anyone has any ideas please chime in! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal 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 an extra in a wrecking shop or a parts store. Testing them is easy – put 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 end of the connector). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which can lead to engine shutdown.

A damaged G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts more quickly than normal, or a misfire in the gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these symptoms. They are cheap and easy-to-find especially when they’re a Bosch sensor like ours. Alternately, the GM version of this unit is also a great option.

5. Tachometer

A failing engine sensor could cause a number of problems within your vehicle. It’s a crucial component of the transmission of your replacement audi a3 key, as it transmits information to the ECU about how fast or slowly the engine is turning. This sensor could cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig and boost, and also transmitting 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. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect an average resistance of 1000 ohms in these areas. This is a common feature across the Audi q7 replacement Key 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU, so you might find them in wrecking yards.