10 Tips For Getting The Most Value From Audi G28

How to Replace an audi Tt key case G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located near the edges of the transmission just above the flywheel ring gear. It transmits 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

The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control the amount of fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can start spark and injectors accordingly.

If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain is stretched or a jump link on the upper chain of timing. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).

It can be a bit difficult to test since there are various pins on the connector, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is at full operation. If you are having problems with this part, check 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 had an abrupt drop in power as if the engine was running out of gas or the injectors are not firing any more. I took out the spark plugs this morning, three were soaked with gasoline and the 4th was dry. I put tissue over each hole in the injector and when I start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one remains closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. So i assume the problem is elsewhere.

I also tried to reset the PID without success. The car can start if the G28 is disconnected and it runs perfectly when it is connected but it still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c even when i unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do. I believe that I've ruled everything else out. However, i'm afraid that i might have missed something. If anyone has any ideas please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80 100 200, UrS and RS2 cars so you can easily find one at a junkyard or at a parts store. It is simple to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed of the crankshaft to make decisions regarding timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either one of these, the diagnostic scanner will show codes that could cause an engine shut down.

A failing G28 sensor can cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, or a misfire while in gear. It is probable that your sensor is failing and needs to be replaced if you encounter any of these signs. The good thing is that they are quite affordable and easily accessible, especially when you're looking at an Bosch model, which is what we have. Alternately, the GM version of this part is also a great option.

5. Tachometer

A damaged engine sensor could cause a variety of issues in your vehicle. It's a vital component of the audi key programmer's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is located on the edge of the transmission, replacement Key for audi a4 above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via a grey 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 located in the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. You can also verify 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. There should be the resistance to be around 1000 ohms in these areas. This part is common across the audi keyless go 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du So, you may find some good ones in wrecking yards.