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

In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is situated at the edge of transmission just above the flywheel gear. It transmits a signal to the ECU through an uncolored wire T55/49, then to the tachometer in 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 a signal to ECU pin T55/49 using a grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig 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 must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors accordingly.

If this sensor fails the ECU will throw 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 chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test since there are different connector pins, and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should read about 1000 ohms. Look for evidence of coolant or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a significant drop in power. It was as if the engine was running out of gas. Or my injectors weren't firing. Today, i pulled out the spark plugs. Three were drenched in gazoline, the fourth 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 closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming the issue is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.

I don't know what to do. I think I've ruled everything else out. However, i'm afraid that I might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 receives signals 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. It is easy to find 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 the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know the position and speed the crankshaft to determine timing of the fuel injector, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

Some of the signs of a failing G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when in gear. If you have any of these problems, it is likely that your sensor is failing and should be replaced. They're inexpensive and audi spare keys easy to locate, especially when they're an Bosch unit like ours. Alternately, the GM version of this component is also a good option.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your vehicle. It's an essential component of the transmission of your Audi because it relays information to the ECU on how fast or slowly the car's engine is turning. This sensor could cause the transmission to malfunction and other replacement car key audi components to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits a signal via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control the flow of fuel and boost and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is a common feature across the audi Spare keys (longisland.Com) 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU So, you may find good ones in wrecking yards.