14 Smart Ways To Spend Your Left-Over Audi G28 Budget How to Replace an Audi G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.

1. Engine Speed Sensor


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

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC and also the location of the camshaft so that it can activate the spark and injectors.

If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).

It can be a bit difficult to test because there are various connector pins, and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When spare audi key is fully functional, it should read about 1000 ohms. Look for evidence of coolant or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had a big cut in power like the engine is out of gas or injectors aren't firing at all. In the morning, i removed the spark plugs, three were soaked with gazoline and the 4th one was dry. I put tissue over each injector hole and when i start the engine with no sparks, the ones that have gazoline pop right out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is in another place.

I also tried to reset the PID with no success. The car will start when the G28 is disconnected and runs fine when it is plugged in however it has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I don't know what to do. I believe that I've eliminated everything else. I'm worried that i might have missed something. If anyone has any suggestions, please let me know! 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 similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. Test them out - put 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 connector's side). They should be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the speed and position of the crankshaft in order to make a decision about fuel injector timing, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

A malfunctioning G28 sensor could cause an inaccurate speed counter for the gearbox, a gearbox that shifts faster than normal, or a misfire while in the gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these symptoms. The good news is that they are very affordable and readily available, especially when you're looking at a Bosch model, like ours. Alternately, GM's version this part would be an option.

5. Tachometer

A failing engine speed sensor could be the cause of many issues in your car. It's an essential component of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is turning. When this sensor fails, it can 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, over the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU then uses and processes this signal to regulate fuel, timig and boost as well as transmitting it to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. There should be a resistance of approximately 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU So, you may find them in wrecking yards.