How to Replace an Audi G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using a grey wire. The ECU utilizes this information to regulate fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also the location of the camshaft so that it can activate the spark and injectors.

If this sensor fails, the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain stretching or a jump link on the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test because there are several pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should read around 1000 ohms. Look for signs of coolant, or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs, 3 were drenched with gazoline the fourth one was dry. When I crank the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline pop out, but the 4th one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is somewhere else.

I also tried to reset the PID but without success. The car will start when the G28 is disconnected and it runs perfectly when it is plugged in, but still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -49c, even if I unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, as i believe that i've completely ruled out all other possibilities. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or parts store. It is easy to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). 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 regarding timing of the fuel injector, for example. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.

A failing G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, and/or a misfire while in the gear. It is possible that your sensor is failing and needs to be replaced if you get more info experience any website of these symptoms. The good news is they are very affordable and readily available particularly in the case of the Bosch model, which is what ours are. Alternately, GM's version this component is a good option.

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It's a vital component of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is spinning. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear. more info It transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU is then able to process this signal to regulate fuel, timig, and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU read more and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This part is common across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 click here RS2 Du So, you may find good ones in wrecking yards.