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How to Replace an audi q3 key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the edge of transmission over the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through a grey wire. The ECU uses this information to control 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 correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger 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 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 each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms if the sensor is at full operation. Look for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday accelerating full speed from highway paytoll, i experienced a big cut in power like the engine is running out of gas or injectors aren't firing at all. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the 4th one was dry. When I crank the engine with no sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline jump out but the 4th stay closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. 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 runs fine with the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62) even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.

I don't know what to do. I feel like i've pretty much ruled everything else out. I'm worried that i might have missed something. Please let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra 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 end of the connector). They must be infinite Ohms.

4. ECU

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

A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire in gear. If you are experiencing any of these problems, it is likely that your sensor is deteriorating and requires replacement. The good news is they are quite affordable and readily available particularly when you're looking at an Bosch sensor, like ours. Alternately, GM's version this part would be a good option.

5. Tachometer

A damaged engine sensor audikey (lt.Dananxun.cn) could cause a number of problems in your car. It's an essential component of the transmission of your audi key replacement near me because it relays information to the ECU about how fast or slowly the engine of the car is turning. If this sensor fails, it will cause problems for the transmission as well as the rest of the Audi a1 car key's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located 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 verify 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 resistance between these two points. This is a standard part that is found across the audi a4 key replacement 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.