15 Trends That Are Coming Up About 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. The sensor is located at the top of the transmission, above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through the grey wire. The ECU uses this information to regulate the amount of fuel and boost. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC, and the location of the camshaft to trigger 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 chain stretch or a jumped link on the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

Testing can be a bit difficult because there are two pins for the connector and they serve different purposes but the best method to test it is to measure resistance between the sensor and the ECU. When the sensor is functional, it should read approximately 1000 ohms. If you're experiencing issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors aren't firing at all. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was unclean. When i crank the engine without sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stay 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 elsewhere.

I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.

I'm not certain what here to do, but i believe that i've ruled out everything else. However, i'm afraid that I might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions more info similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the website spare in a salvage shop or a parts store. It is simple to test them to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector more info end up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must be aware of the speed and position of the crankshaft to make decisions regarding timing of fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will display the codes that could trigger an engine shutdown.

Some of the symptoms of a failing G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal and/or misfiring when you're in gear. If you experience any of these problems, it is likely that your sensor is going bad and should be replaced. The good news is they are very cheap and easy to find, especially if you're looking at the Bosch model, which is what ours are. Alternatively, the GM version of this unit is also a great option.

5. Tachometer

A faulty engine speed sensor could be the cause of a slew of issues in your vehicle. It's a crucial component of the transmission in your Audi since it sends information to the ECU about how fast or slowly the engine is spinning. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, as well as timig. It also sends it to the G5 Tachometer located 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 via pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect an average resistance of 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 range, beginning with audi key replacement the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.