How to Replace an new audi key G28 Engine Speed Sensor

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located near the edges of the transmission, above the flywheel ring gear. It sends a message to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors in the right way.

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

Testing can be a bit difficult since there are two pins for the connector and audi tt key programming they perform different functions but the most effective method of testing it is to measure the resistance between the sensor and the ECU. When the sensor is operational, it should read approximately 1000 ohms. If you are having problems with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power as if the engine was running out of gas or the injectors are not firing at all. In the morning, i removed the spark plugs, three were drenched in gazoline, the fourth was dry. When I crank the engine with no sparks i put tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stays shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. i get 0ohm. So i assume the problem is elsewhere.

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

I don't know what to do. I believe that I've eliminated everything else. I'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from 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 wrecking yard or in a local parts store. Testing them is easy by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft in order to make decisions about timing of the fuel injector, for example. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will display codes that could lead to an engine shut down.

Some of the symptoms of a failing G28 sensor are an inaccurate rev counter for Audi tt Key Programming the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. It is likely that your sensor is failing and requires to be replaced if you notice any of these signs. The good news is they are quite affordable and readily available, especially in the case of the Bosch unit which is what ours are. Alternately, GM's version this component is an excellent choice.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind many problems in your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor can cause the transmission to malfunction and other components in the car to be affected.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate the flow of fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. It should show around 1000 ohms of resistance between these two points. This is a common feature across the audi tt key programming 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du So, you may find good ones in wrecking yards.