How to Replace an Programming Audi Key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU through an uncolored wire T55/49, Audi Etron Key - Dokuwiki.Stream, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation.

If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).

Testing is a bit challenging because there are two pins for the connector and they perform different functions but the best method of testing it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when it is in full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or the injectors are not firing any more. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. I placed a tissue over each injector hole, and when i start the engine without sparks, the 3 with gazoline jump out. The 4th one remains closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I think the issue is elsewhere.

I also tried to reset the PID with no success. The car is able to start if the G28 is disconnected and runs fine when it is connected however it is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.

I don't know what to do. I believe that I've ruled everything else out. I'm afraid i may have missed something. If anyone has any suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter 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 salvage yard or from a parts store. It is simple to test them by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

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

A failing G28 sensor could result in an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, and/or a misfire in the gear. If you experience any of these problems, it is most likely that your sensor is failing and needs replacing. The good thing is that they are very cheap and easy to find, especially in the case of a Bosch sensor, which is what we have. Alternately, the GM version of this component is also a good choice.

5. Tachometer

A failing engine speed sensor could be the cause of many issues with your car. It's a crucial component of the transmission in your audi smart key replacement because it relays information to the ECU about how fast or slow the car's engine is turning. If this sensor fails, it could disrupt the performance of the transmission as well as the other car's components.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test the sensor for 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 via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those points. This is a standard part that is found across the audi key replacement cost uk 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.