How to Replace an spare audi key G28 Engine Speed Sensor

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located at the edge of transmission over the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to regulate fuel and boost. It also sends a signal to the G5 tachometer in the instrument cluster.

The sensor is used to correlate 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 trigger spark and injectors accordingly.

If this sensor fails, the ECU will throw a P00160 code 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. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).

It can be a bit difficult to test because 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 the sensor is at full operation. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced an abrupt drop in power as if the engine was running out of gas or the injectors aren't firing any more. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was unclean. I placed a tissue over each hole in the injector and when i start the engine without sparks, the three that have gazoline pop right out. The fourth one remains shut. I tested the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. Therefore, i think the issue is in another place.

I also tried to reset PID but without success. The car is able to 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 coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.

I'm not certain what to do, i believe that i've eliminated everything else. I'm concerned that i may have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. It is simple to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.

4. ECU

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

Some of the signs of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or misfiring when in gear. It is probable that your sensor is failing and requires to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate especially in the case of an Bosch unit like ours. Alternatively, GM's version of this part is a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind a slew of problems in your vehicle. It's a vital component of your audi etron key's transmission, as it sends information to the ECU about how fast or replacement audi key fob New Key - Mozillabd.Science - slow the vehicle's crankshaft is spinning. If the sensor fails, it can disrupt the performance of the transmission as well as the other car's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to regulate 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 failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these points. This is a common component across the audi a3 key fob 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.