How to Replace an audi car key holder G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via an uncolored wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, directly above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU uses this information to regulate the amount of fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors according to the situation.

If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).

It's a bit tricky to test as there are different connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when it is operating at its maximum. Look for signs of coolant or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a massive drop in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was unclean. I placed a tissue over each injector hole and when i turn the engine on without sparks, the three that have gazoline pop right out. The fourth one remains shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. So i assume the problem is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged and runs fine when it is connected but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

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

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent 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 locate an extra in a wrecking shop or parts store. Test them out - put 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 must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to know the speed and position of the crankshaft to make decisions regarding timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either one of these, the diagnostic scanner will display codes that could cause the engine shutting down.

Some of the symptoms of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal and/or misfiring when in gear. If you are experiencing any of these problems, it is likely your sensor is going bad and should be replaced. The good news is they are very affordable and easy to find, especially when you're looking at the Bosch model, which is what ours are. Alternatively, GM's version of this part would be an option.

5. Tachometer

A faulty engine speed sensor could be a cause for many issues in your vehicle. It's a vital component of the audi car key holder's transmission as it sends information to the ECU about how the car's crankshaft is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It transmits signals via gray wire to ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms in these areas. This is a typical component across the audi a3 key fob replacement audi connect key fob replacement cost (click the following webpage) 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.