The Most Pervasive Problems 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. The sensor is located near the transmission's edge, above the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to link the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors in the right way.

If this sensor audi a3 key fob replacement (https://crackbread0.werite.net/) fails, the ECU will show an error code P00160 which indicates that 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 won't appear on its own without additional information from other sensors (G4 and G40).

It is a little tricky to test since there are various pins on the connector, and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when it is at full operation. If you're having issues with this part, check for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a massive decrease in power. It was like the engine had run out of gas. Or my injectors were not firing. I took out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was dry. When I crank the engine without sparks, i place a tissue on the top of each hole in the injector, the 3 drenched with gazoline jump out but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID but with no luck. The car is able to start if the G28 is unplugged and is running fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of -49c even when i unplug it. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, i believe that i've completely ruled out all other possibilities. I'm afraid i may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80, 100 200, UrS and RS2 cars so you can easily find one at a junkyard or from a parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft in order to make a decision about timing of the fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.

The signs of a failed G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when you're in gear. If you are experiencing any of these problems, it is most likely that your sensor is going bad and should be replaced. The good news is that they are very affordable and easy to find, especially in the case of a Bosch sensor, which is what ours are. If you prefer, GM's version of this component is an excellent choice.

5. Tachometer

A failing engine speed sensor could be a cause for many problems in your car. It's a crucial component of the transmission of your audi key fobs car key cover (www.hulkshare.com website), as it transmits information to the ECU regarding how fast or slowly the engine of the car is turning. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends an electrical signal through 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 as well as sends it on to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Additionally, you can check continuity between pin 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. You should observe approximately 1000 ohms of resistance between those points. This is the same across the audi tt key programming 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU So, you may find good ones in wrecking yards.