How to Replace an audi key copy G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge over the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control boost and fuel. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC, and the location of the camshaft so that it can activate the spark and injectors.

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

Testing is a bit challenging because there are two connector pins, and they serve different purposes but the best way to test it is to measure the resistance between the sensor and the ECU. When the sensor is fully operational, it should read about 1000 ohms. If you are having problems with this sensor, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge reduction in power. It was as if the engine was running out of gas. Or, my injectors were not firing. In the morning, i removed the spark plugs, 3 were soaked with gazoline and the fourth one was dry. When I crank the engine with no sparks, I put a piece of tissue on the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID but with no luck. The car is able to start when the G28 is unplugged and is running fine when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.

I'm not sure what to do, but i think i've pretty much ruled out everything else. But i'm worried that I might have missed something. If anyone has suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or in a local parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that has to be aware of the speed and position of the crankshaft in order to make a decision about timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.

Some of the symptoms of a failing G28 sensor are an inaccurate rev counter in 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 likely that your sensor is deteriorating and requires replacement. The good news is they are very cheap and easily accessible, especially in the case of the Bosch sensor, which is what ours are. You can also choose the GM version of this component is also a good choice.

5. Tachometer

A damaged engine sensor could cause a variety of issues in your vehicle. It's a vital component of your audi key blade car key case (themirch.com)'s transmission, because it communicates to the ECU about how the car's crankshaft is rotating. When this sensor fails, it will cause problems for the transmission as well as the rest of the car's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for failure by checking 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 [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms resistance between those points. This part is common across the audi car key 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 them in wrecking yards.