How to Replace an audi advance key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the top 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

The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through an uncolored wire. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer within 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 reached TDC and also where the camshaft lies to trigger the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of 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 provided by other sensors (G4 or G40).

It's a bit tricky to test since there are different pins on the connector, and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is in full operation. If you're experiencing issues with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced a big cut in power like the engine is running out of gas or injectors aren't firing anymore. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the 4th was dry. I placed a tissue over each hole in the injector and when i start the engine without sparks, the 3 with gazoline jump right out. The 4th one stays shut. I tested the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming that the issue is somewhere else.

I also tried to reset the PID but without success. The car can start if the G28 is unplugged and it runs perfectly when it is connected but it still is experiencing intermittent misfires at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c even when i unplug it. I also noticed that the gauge replacement key for audi a3 oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, but i feel i have pretty much eliminated everything else. But i am afraid I may have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or from a parts store. Test them out by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black end of the connector). 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 timing of the fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

The signs of a malfunctioning G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal, and/or a misfire when in gear. If you experience any of these issues, it is most likely that your sensor is failing and requires replacement audi A3 key. They are cheap and easy-to-find particularly if they're an Bosch sensor like ours. Alternatively, the GM version of this part is also a great option.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems in your vehicle. It's a crucial component of the transmission of your audi spare keys since it sends information to the ECU on how fast or slow the engine of the car is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.

The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49, via a grey wire. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is a common part that is found across the audi replacement key cost 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.