How to Replace an replacement key audi G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated at the edge of transmission, above the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission, above the flywheel ring gear, Audi Car key cover the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through an uncolored wire. 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 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 so it can trigger spark and injectors in the right way.

If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test because there are various connector audi Q7 key pins, Replacement Audi Car Key and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should be reading about 1000 ohms. Look for evidence of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a massive decrease in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was unclean. When I start the engine with no sparks, i place a tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th one stays shut. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get 0ohm. Therefore, i think the issue is somewhere else.

I also tried to reset the PID but without success. The car can start if the G28 is not plugged in and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.

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 suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or a parts store. It is simple to test them to do - just put your DMM in resistance mode and measure the resistance 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 of our 20vt turbo (3B AAN ABY) engines must know the position and speed the crankshaft to determine fuel injector timing, etc. It utilizes 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 shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal, and/or a misfire when in gear. It is probable that the sensor is failing and requires to be replaced if you encounter any of these signs. The good news is they are very cheap and easily accessible particularly if you're looking at an Bosch unit which is what we have. If you prefer, GM's version of this part is an option.

5. Tachometer

A damaged engine sensor could cause a myriad of issues in your vehicle. It's a crucial component of the transmission of your audi replacement key fob because it relays information to the ECU regarding how fast or slow the engine is spinning. If this sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.

The G5 engine speed sensor is located at the edge of the transmission, above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU utilizes this signal to control the flow of fuel and boost and also to timigrate. It also relays it to the G5 Tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms between these points. This is a standard component across the audi key shell 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.