How to Replace an audi a4 replacement key G28 Engine Speed Sensor

Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission, above the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49), then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer in 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 to trigger the spark and injectors.

If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jump in the chain link of the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).

It’s a bit tricky to test since there are several pins on the connector, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is at full operation. If you’re having issues with this component, look for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power like the engine is running out of gas or injectors aren’t firing at all. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When i crank the engine with no sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline pop out, but the 4th stays shut. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. Therefore, i think the issue is in another place.

I also tried to reset the PID without success. The car key cover audi can start when the G28 is unplugged and runs fine when it is connected however it has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of that is -49c even after unplugging it. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.

I don’t know what to do. I believe that I’ve eliminated everything else. But i am afraid I may have missed something. Let me know should 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 the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a salvage yard or at a parts store. It is easy to test them – simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector’s end facing up). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know the position and speed of the crankshaft to determine timing of the fuel injector, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, or a misfire in the gear. It is probable that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is they are very affordable and readily available particularly when you’re looking at a Bosch model, like ours. Alternately, the GM version of this component is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues in your car. It’s a vital component of the audi keys Replacement Cost‘s transmission as it sends information to the ECU about how the car’s crankshaft is rotating. If the sensor fails, it can cause problems for the transmission, as well as the rest of the car’s components.

The G5 engine speed sensor Programming Audi Key is situated on the outside of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through a grey wire. The ECU is then able to process the signal to control fuel, timig, and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can check 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 see a resistance of approximately 1000 ohms between these two points. This is the same across the audi keyless entry 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du So, you may find them in wrecking yards.