How to Replace an audi lost key G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission just above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU uses this information to regulate the amount of fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used to link the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors according to the situation.

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

Testing is a bit challenging as there are two different connector pins, and they have different functions however the best way to test it is by measuring resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is in full operation. If you're experiencing 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 had massive power loss as if the engine was running out of gas or the injectors are not firing anymore. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. When I start the engine with no sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found zero ohm. So i assume the problem is somewhere else.

I also tried to reset the PID but 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 coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.

I'm not certain what to do, i feel i have pretty much completely ruled out all other possibilities. I'm afraid i may have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80 100, 200, UrS and RS2 cars so you can easily find one at a salvage yard or in a local 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's side up) and 2 (2nd from the left on the black connector's end). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft in order to make decisions about timing of the fuel injector, for example. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could lead to an engine shutdown.

A malfunctioning G28 sensor could result in an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, or an unfire when in gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these signs. The good news is they are very cheap and readily available particularly when you're looking at a Bosch model, which is what we have. You can also choose the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind numerous issues with your vehicle. It's an essential component of the transmission of your audi connect key, as it transmits information to the ECU about how fast or slow the car's engine is spinning. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49, via an uncolored 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 inside the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between these two points. This is a standard part that is found across the replacement audi keys replacement key for audi replacement key for audi a3 cost uk (www.google.co.ao) 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.