How to Replace an Audi Replacement Key Cost Uk G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge just above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through the 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 located in the instrument cluster.

The sensor serves as a reference replacement key for audi comparing with 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 according to the situation.

If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test as there are various pins on the connector, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is at full operation. Examine for signs of coolant or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll i had massive power loss like the engine is running out of gas or the injectors aren't firing anymore. Today, i pulled out the spark plugs, three were drenched with gazoline the 4th one was dry. When I start the engine, there are no sparks, i place a tissue on top of each injector hole and the 3 drenched with gazoline leap out, however the 4th stays closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. I think the issue is somewhere else.

I also tried to reset the PID without success. The car is able to start when the G28 is disconnected and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when I crank up the engine.

I don't know what to do. I think I've ruled everything else out. I'm afraid i may have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent by 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. It is easy to find a spare in a wrecking shop or parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that must be aware of the speed and position of the crankshaft to make a decision about fuel injector timing etc. To do this, it uses 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 lead to the engine shutting down.

The signs of a failed G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or misfiring when you are in gear. It is likely that your sensor is failing and needs to be replaced if you notice any of these symptoms. They are cheap and easy-to-find, especially if they're a Bosch sensor like ours. Alternatively, the GM version of this part is also a good option.

5. Tachometer

A failing engine speed sensor could be the cause of numerous issues in your vehicle. It's a vital component of your replacement audi a4 key's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it could cause problems for the transmission, as well as the other car's components.

The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU then processes this signal to control fuel, timig, and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can check the sensor for failure by checking 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. It should show approximately 1000 ohms of resistance between those points. This is a common feature across the audi key fob replacement 80-100-200-RS2 model, ranging beginning with the 1985 MC and Audi Car Keys up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.