How to Replace an audi tt key replacement G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through an uncolored wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test because there are different pins on the connector, and each has its own functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should be reading approximately 1000 ohms. Examine for audi replacement Key Service signs of coolant, or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday, when accelerating from highway paytoll at maximum speed I noticed a massive drop in power. It was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. When I crank the engine without sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline leap out, however the 4th stays shut. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero Ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID without success. The car key cover audi will start when the G28 is unplugged, and it works fine when the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.

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

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 sender, Programming Audi Key and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or 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 end facing upwards). They should 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 about timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger an engine shutdown.

Some of the symptoms of a failed G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when in gear. It is likely that the 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. If you prefer, GM's version of this part would be an excellent choice.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your vehicle. It's a crucial component of the transmission of your audi q5 key since it sends information to the ECU regarding how fast or slowly the engine is turning. When this sensor fails, it could cause problems for the transmission as well as the rest of the car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to control fuel, timig, and boost as well as sends it on 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 ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between these two points. This is a common feature across the audi key fob not working 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU, so you might find some good ones in wrecking yards.