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 audi replacement key service near me the edges of the transmission just above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via the grey wire. The ECU utilizes this information to regulate fuel and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors according to the situation.

If this sensor fails to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

It's a bit tricky to test as there are various pins on the connector, and each one has different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is at full operation. Check for signs of coolant or oil in the connector bay if you have issues with this component.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power like the engine is running out of gas or the injectors aren't firing anymore. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. When I crank the engine with no sparks, I put a piece of tissue on top of each injector hole and the 3 that were drenched in gazoline jump out but the 4th stay closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero ohm. I think the issue is in another location.

I also tried to reset PID but 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 still occurs at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. 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 feel i have pretty much ruled out everything else. 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 is activated by a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft to make decisions about timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.

Some of the symptoms of a failed G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or misfiring when in gear. It is probable that your sensor is failing and needs to be replaced if you notice any of these signs. The good thing is that they are quite affordable and easily accessible, especially if you're looking at a Bosch unit which is what ours are. You can also choose the GM version of this unit is also a great option.

5. Tachometer

A failing engine speed sensor could be a cause for numerous issues in your vehicle. It is an important part of the transmission of your audi car key because it relays information to the ECU about how fast or slowly the engine of the car is turning. When this sensor fails, it could affect the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Also, 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 of resistance between these two points. This is a common feature across the audi car key 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du, so you might find some good ones in wrecking yards.