Some Of The Most Ingenious Things That Are Happening With Audi G28 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. This sensor is situated at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor


The grey wire is located on the edge of transmission, above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also where the camshaft lies in order to activate the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).

It is a little tricky to test as there are different pins on the connector, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should be reading about 1000 ohms. Examine for signs of coolant, or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors are not firing at all. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the 4th was dry. When i crank the engine with no sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th one stays shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero Ohm. I think the issue is in another location.

I also tried to reset the PID without success. official website is able to start when the G28 is not plugged in and it runs perfectly when it is connected however it is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows a temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, as i think i've pretty much ruled out everything else. I'm worried that i might have missed something. If anyone has suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or a parts store. It is easy to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these, the diagnostic scanner will show codes that could cause the engine shutting down.

Some of the signs of a failing G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these signs. The good news is they are very affordable and easily accessible, especially if you're looking at the Bosch unit which is what ours are. Alternatively, the GM version of this part is also a good choice.

5. Tachometer

A faulty engine speed sensor could be the cause of numerous issues in your car. advanced key audi 's an essential component of your Audi's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is spinning. If the sensor fails, it could affect the performance of the transmission, as well as the rest of the car's components.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It transmits a signal via 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 in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those points. This is a common component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.