Why Nobody Cares About Audi G28

How to Replace an audi replacement keys G28 Engine Speed Sensor

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

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor serves as a reference for comparing with 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 accordingly.

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

It can be a bit difficult to test as there are different pins on the connector and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is in full operation. If you are having problems with this sensor, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced massive power loss like the engine is out of gas or injectors aren't firing anymore. I pulled out the spark plugs this morning, three were soaked in gasoline, and the fourth was unclean. I put tissue over each injector hole, and when i start the engine without sparks, the three that have gazoline pop right out. The 4th one remains shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. I assume that the problem is elsewhere.

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

I don't know what to do. I think I've ruled everything else out. However, i'm afraid that I may have missed something. Please let me know If you have any suggestions! 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 identical to 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 in a local parts store. It is easy 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's end facing up). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed the crankshaft to determine timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, audi Key shell - http://www.zybls.Com/home.php?mod=space&uid=832672, you will receive codes on the diagnostic scanner which could cause engine shut down.

A failing G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, or an unfire when in gear. It is possible that your sensor is failing and needs to be replaced if you experience any of these signs. They're inexpensive and easy to locate particularly when they're a Bosch unit like ours. Alternately, GM's version this component is a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of many issues in your car. It's an essential component of your audi tt key fob's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This part is common across the audi replacement key service 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 Du So, you may find good ones in wrecking yards.