How to Replace an replacement audi a4 key G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission, above the flywheel ring gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through an uncolored wire. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.

If this sensor fails the ECU will display the P00160 error, 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 chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

Testing can be a bit difficult because there are two connector pins, and they have different functions but the most effective method to test it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should read approximately 1000 ohms. If you're having issues with this part, check for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power like the engine is out of gas or the injectors are not firing any more. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was unclean. I put tissue over each hole in the injector and when I start the engine without sparks, the three with gazoline jump right out. The 4th one stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. I think the issue is in another location.

I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when I crank up the engine.

I don't know what to do. I feel like i've pretty much eliminated everything else. But i'm worried that I may 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 from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. Testing them is easy by putting your DMM in resistance mode and take measurements 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

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft to make a decision about timing of the fuel injector, for example. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could cause an engine shutdown.

The signs of a failed G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal and/or misfiring when in gear. If you are experiencing any of these issues, it is likely that your sensor is deteriorating and needs replacing. The good news is they are very cheap and readily available, especially if you're looking at a Bosch sensor, audi key replacement near me like ours. Alternatively, the GM version of this part is also a good choice.

5. Tachometer

A damaged engine sensor could cause a number of problems in your car. It is an important part of the transmission in your audi car keys, as it transmits information to the ECU about how fast or slow the car's engine is spinning. If this sensor fails, it will cause problems for the transmission, as well as the other car's components.

The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU then processes this signal to control fuel, timig, and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between these two points. This is a typical component across the audi tt replacement key 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.