How to Replace an audi Replacement Key cost 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 top of the transmission just above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer 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 signals to ECU pin T55/49 through a grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and where the camshaft lies to trigger the spark and injectors.

If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumpy chain link in the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).

It's a bit tricky to test since there are different pins on the connector and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from 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 weren't firing. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. I put a piece of tissue over each injector hole and when I turn the engine on without sparks, the 3 with gazoline jump right out. The fourth one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. I assume that the problem is elsewhere.

I also tried to reset the 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 problem continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.

I don't know what to do. I think I've eliminated everything else. I'm concerned that i may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner that can cause the engine to shut down.

The signs of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is likely that your sensor is failing and requires to be replaced if you encounter any of these signs. The good thing is that they are very cheap and readily available particularly when you're looking at a Bosch model, which is what we have. If you prefer, GM's version of this component is an excellent choice.

5. Tachometer

A failing engine sensor could cause a variety of issues within your vehicle. It's an essential component of your audi a1 car key's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is turning. This sensor could cause the transmission to malfunction and other car components to be affected.

The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU then processes this signal to control the flow of fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, Audi etron key you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 and pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a typical part across the audi keyless entry 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.