What Is Audi G28 History Of Audi G28

How to Replace an audi tt key replacement G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

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

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.

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

Testing is a bit tricky as there are two different pins replacement key for audi a4 the connector and they serve different purposes however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is at full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had a big cut in power as if the engine was running out of gas or the injectors aren't firing any more. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the 4th was dry. I placed a tissue over each injector hole and when I turn the engine on without sparks, the ones that have gazoline pop right out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got 0ohm. I'm assuming that the issue is somewhere else.

I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is zero.

I'm not certain what to do, i think i've pretty much ruled out everything else. But i am afraid i might have missed something. If anyone has any ideas please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or a parts store. It is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines requires to be aware of the position and speed the crankshaft in order to make a decision about timing of fuel injectors, etc. To accomplish this, it uses a Crank Position Sensor Programmed (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner that can cause the engine to shut down.

Some of the symptoms of a failing G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or a misfire when you're in gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is that they are very cheap and easy to find particularly if you're looking at an Bosch unit like ours. Alternatively, the GM version of this part is also a great option.

5. Tachometer

A damaged engine sensor could cause a myriad of issues in your vehicle. It is an important part of the transmission of your audi replacement key cost since it sends information to the ECU about how fast or slow the engine is turning. If this sensor fails, it will disrupt the performance of the transmission and the other car's components.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU then uses and processes the signal to control the flow of fuel, timig and repairer boost, and also transmitting it 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. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms resistance between those two pins. This is a common part that is found across the audi lost key 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.