How to Replace an audi keys replacement G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through a grey wire. The ECU uses this information to regulate the amount of fuel 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 the location of the camshaft so it can start spark and injectors in the right way.

If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing can be a bit difficult because there are two connector pins, and they serve different purposes but the best method of testing it is to measure the resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is at full operation. If you're experiencing issues with this sensor, look for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or injectors aren't firing at all. I pulled out the spark plugs this morning, 3 were soaked with gasoline and the 4th was dry. I put a piece of tissue over each injector hole and when I start the engine with no sparks, the ones that have gazoline pop right out. The 4th one remains closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero ohm. I'm assuming the issue is in another place.

I also tried to reset the PID without success. The car is able to start if the G28 is not plugged in and it runs perfectly when it is plugged in however it has the intermittent misfire issue 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 bars but the actual pressure is 0.

I don't know what to do. I feel like i've pretty much eliminated everything else. But i'm worried that I might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or parts store. Test them out - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's end). They should be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, 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 show codes that could cause an engine shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or misfiring when you're in gear. It is probable that your sensor is failing and needs to be replaced if you experience any of these symptoms. The good news is that they are quite affordable and easy to find, especially if you're looking at the Bosch sensor, which is what ours are. You can also choose the GM version of this part is also a good choice.

5. Tachometer

A faulty engine speed sensor could be the reason behind a slew of problems in your vehicle. It is a crucial part of the audi tt key programming's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to fail and other components in the car to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU is then able to process this signal to regulate fuel, timig and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Also, 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 as well as pin T26a/12. You should observe approximately 1000 ohms of resistance between those two pins. This is the same across the audi a3 keys 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU You may also find good ones in wrecking yards.