The Most Profound Problems In 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 near the transmission's edge just above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, directly above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU uses this information to regulate the amount of fuel and boost. It also sends a signal to the G5 tachometer in the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.

If this sensor fails the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing can be a bit difficult since there are two pins for the connector and they perform different functions but the best method to test it is to measure resistance between the sensor and the ECU. If the sensor is functional, it should read around 1000 ohms. If you are having problems with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a significant drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. This morning i pull out the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I put a piece of tissue over each injector hole and when I start the engine without sparks, the 3 with gazoline jump right out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. I assume that the problem is in another location.

I also tried to reset PID without success. The car can start when the G28 is unplugged and runs fine when it is connected but it still has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.

I'm not sure what to do, i feel i have pretty much eliminated everything else. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. Test them out - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.

4. ECU

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

A damaged G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, or an unfire when in gear. If you are experiencing any of these problems, it is likely your sensor is failing and needs read more replacing. The good news is they are quite affordable and readily available, especially in the case of a Bosch sensor, like ours. Alternately, the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems within your vehicle. It's an essential component of the Audi's transmission since it relays information to the ECU about how fast or slow the click here vehicle's crankshaft is rotating. This sensor could cause the transmission to malfunction and other car components to be affected.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate the flow of fuel, timig and boost and then transmitting it check here to the G5 Tachometer located in the instrument cluster. You can check the sensor for website any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You read more should detect an average resistance of 1000 ohms in these areas. This is a common part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.