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

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through a grey wire. The ECU uses this information to regulate boost and fuel. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used to link 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 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 be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test as there are various connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. If the sensor is functional, it should read around 1000 ohms. Examine for evidence of coolant or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power like the engine is running out of gas or the injectors aren't firing anymore. In the morning, i removed the spark plugs. Three were drenched with gazoline the 4th one was dry. When I start the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th one stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I think the issue is somewhere else.

I also tried to reset the PID but with no luck. The car can start if the G28 is not plugged in and is running fine when it is plugged in however it is experiencing intermittent misfires at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do, but i think i've pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works 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 easy to test them - simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed of the crankshaft to determine timing of the fuel injector, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go wrong, you will receive codes on the diagnostic scanner which can cause the engine to shut down.

A damaged G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, and/or a misfire in the gear. It is probable that the sensor is failing and requires to be replaced if you notice any of these signs. They're cheap and easy to find particularly when they're a Bosch sensor like ours. Alternately, GM's version this component is an option.

5. Tachometer

A faulty engine speed sensor could be the reason behind numerous issues with your car. It's a crucial component of the transmission of your Audi Smart Key Replacement since it sends information to the ECU about how fast or slow the car's engine is spinning. If the sensor fails, it could cause problems for the transmission and the other car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU uses 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 the sensor key for audi any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This is a common feature across the audi key 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 DU You may also find good ones in wrecking yards.