How to Replace an audi car keys G28 Engine Speed Sensor

Charles the Humble Technician teaches 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 sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 through an uncolored wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors accordingly.

If this sensor fails, the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain stretching or a jump link on the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test because there are different connector pins, and each one has different 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 if the sensor is operating at its maximum. If you're having issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at a high speed I noticed a massive decrease in power. It was as if the engine had run out of gas. Or my injectors weren't firing. I took out the spark plugs this morning, three were soaked in gasoline, and the fourth was dry. I placed a tissue over each hole in the injector and when i start the engine with no sparks, the ones with gazoline jump out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. I assume that the problem is in another location.

I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.

I'm not sure what to do. I believe that I've eliminated everything else. However, i'm afraid that I might have missed something. If anyone has suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. It is easy to test them - simply put 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

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that needs to be aware of the speed and position of the crankshaft in order to make decisions regarding fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.

A malfunctioning G28 sensor can cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, and/or a misfire while in the gear. It is likely that the sensor is failing and requires to be replaced if you experience any of these symptoms. The good news is that they are quite affordable and easy to find particularly if you're looking at the Bosch sensor, like ours. Alternatively, the GM version of this unit is also a good option.

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It's a crucial component of the transmission of your audi lost key because it relays information to the ECU about how fast or slowly the engine is turning. This sensor could cause the transmission to fail 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 transmits signals via gray wire to ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig, and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of 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 [79trace [79]) and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a standard part across the audi a3 replacement key smart key replacement (from the Blog Kids blog) 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.