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

Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 via a grey wire. The ECU utilizes this information to control fuel and boost. It also sends signals to the G5 Tachometer located in the instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors in the right way.

If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).

It's a bit tricky to test since there are various connector pins, and each one has different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading around 1000 ohms. Examine for signs of coolant, or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or injectors aren't firing anymore. I took out the spark plugs this morning, 3 were soaked with gasoline and the 4th was dry. I put tissue over each injector hole and when i start the engine with no sparks, the three with gazoline jump right out. The fourth one remains closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. So i assume the problem is somewhere else.

I also tried to reset the PID but with no luck. The car can start when the G28 is disconnected and is running fine when it is connected but it still has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.

I'm not sure what to do, but i think i've pretty much eliminated everything else. But i am afraid I might have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or at a parts store. Test them out - 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 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 in order to make a decision about timing of the fuel injector, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will display codes that could cause an engine shutdown.

The signs of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when you are in gear. If you are experiencing any of these issues it is most likely that your sensor is failing and replaced should be replaced. The good news is they are very cheap and easily accessible particularly if you're looking at an Bosch model, which is what we have. Alternatively, the GM version of this component is also a good option.

5. Tachometer

A damaged engine sensor could cause a myriad of issues in your car. It's an essential component of the audi car key replacement's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig and boost and then transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those points. This is a common feature across the audi key copy 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du You may also find some good ones in wrecking yards.