How to Replace an replacement audi car key 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 just above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indication to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC, and where the camshaft lies to trigger the spark and injectors.

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

Testing is a bit tricky because there are two connector pins and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. If the sensor is operational, it should be reading around 1000 ohms. If you're having issues with this sensor, look replacement key for audi signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a massive decrease 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, three were soaked with gasoline and the 4th was dry. When I start the engine, there are no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 drenched with gazoline jump out but the 4th one stays shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero ohm. I'm assuming that the issue is elsewhere.

I also tried to reset PID without success. The car will start when the G28 is not plugged in and is running fine when it is connected, but still is experiencing intermittent misfires 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 when the actual pressure is 0.

I'm not sure what to do, i believe that i've eliminated everything else. But i am afraid I may have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor is identical to the G4 and both function in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is simple to test them by putting 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 end of the connector). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and speed 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 either of these go bad you will get codes on the diagnostic scanner that can lead to engine shutdown.

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you are experiencing any of these issues it is likely your sensor is deteriorating and should be replaced. The good thing is that they are quite affordable and readily available, especially in the case of an Bosch unit which is what we have. If you prefer, GM's version of this part is an option.

5. Tachometer

A faulty engine speed sensor could be the cause of numerous problems in your car. It's a crucial component of the transmission in your audi tt key fob not working because it relays information to the ECU about how fast or slowly the car's engine is turning. If the sensor fails, it will disrupt the performance of the transmission as well as the rest of the car's components.

The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control the flow of fuel and boost as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. Additionally, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. You should see a resistance of approximately 1000 ohms in these areas. This is a standard part across the audi Replacement key service 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.