The Three Greatest Moments In Audi G28 History

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 edge of transmission, above the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 via a grey wire. The ECU utilizes this information to control fuel and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation.

If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and could indicate chain stretch or a jumped link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test because there are several connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms if the sensor is in full operation. If you're experiencing issues with this component, look for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or the injectors aren't firing any more. In the morning, i removed the spark plugs. Three were drenched in gazoline, the 4th one was dry. I placed a tissue over each injector hole and when I start the engine without sparks, the 3 that have gazoline pop right out. The 4th one stays closed. I tested the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I think the issue is somewhere else.

I also tried to reset PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I'm not sure what to do. I feel like i've pretty much all other possibilities out. But i am afraid I might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal from the RPM sensor. The GM-style sensor is the same as 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 from a parts store. Test them out to do - just put your DMM in resistance mode and read more measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines requires to be aware of the position and speed of the crankshaft to make decisions regarding timing of fuel injectors, etc. To do this, it makes website use of a website Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will show codes that could cause an engine shut down.

Some of the symptoms of a failed G28 sensor include an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you're in gear. It is possible that the sensor is failing and get more info requires to be replaced if you encounter any of these signs. The good news is they are very cheap and easy to find, especially when you're looking at the Bosch model, like ours. Alternatively, the GM version of this part is also a good option.

5. Tachometer

A damaged engine sensor could cause a myriad of issues within your vehicle. It's an essential component of the transmission in your Audi, as it transmits information to the ECU regarding how fast or slow the car's engine is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.

The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then uses and processes here this signal to regulate fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by checking continuity from 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 as well as pin T26a/12. There should be an average resistance of 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du You may also find some good ones in wrecking yards.