Why Nobody Cares About Audi G28

How to Replace an audi a3 key fob replacement G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located near the edges of the transmission above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU uses this information to control boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC and audi a3 key replacement also the position of the camshaft, in order to activate the spark and injectors.

If this sensor fails, the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating chain stretch or a jumped link on the upper chain of timing. However, the error code won't be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging because there are two pins for the connector and they have different functions but the most effective method to test it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms when it is in full operation. If you're having issues with this sensor, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or my injectors were not firing. This morning i pull out the spark plugs. Three were soaked with gazoline and the fourth was dry. When I start the engine with no sparks, I put a piece of tissue on the top of each hole in the injector and the 3 that were drenched in gazoline pop out, but the 4th stays closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero Ohm. I assume that the problem is in another location.

I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.

I'm not certain what to do, but i feel i have pretty much eliminated everything else. But i'm worried that I may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 gets 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. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could cause an engine shut down.

The signs of a failing G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or a misfire when you're in gear. If you have any of these issues it is likely that your sensor is failing and needs replacing. The good news is that they are very cheap and easily accessible, especially if you're looking at the Bosch unit which is what we have. You can also choose the GM version of this unit is also a great option.

5. Tachometer

A malfunctioning engine speed sensor could be a cause for many issues with your car. It's a vital component of your audi car key Case's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine speed sensor is located on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU then processes this signal to regulate the flow of fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Also, 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 as well as pin T26a/12. You should detect the resistance to be around 1000 ohms between these two points. This is a standard part across the audi tt replacement key 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.