Why Nobody Cares About Audi G28

How to Replace an replacement audi a3 key G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic shows 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 the grey wire T55/49 and 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 G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through an uncolored wire. The ECU uses this information to regulate boost and fuel. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference to correlate with 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 accordingly.

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

It's a bit tricky to test as there are several pins on the connector and each one has different functions. The best way to do 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. If you're having issues with this component, look for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had a big cut in power like the engine is out of gas or the injectors aren't firing any more. Today, i pulled out the spark plugs, 3 were drenched in gazoline, the fourth was dry. I put a piece of tissue over each injector hole, and when I start the engine without sparks, the ones 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'm assuming the issue is elsewhere.

I also tried to reset the PID with no success. The car can start when the G28 is not plugged in and it runs perfectly when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, as i think i've pretty much ruled out everything else. I'm worried that i might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter 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 junkyard or in a local parts store. It is simple to test them - simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and Audi a1 key Fob speed of the crankshaft to determine timing of the fuel injector, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, you will receive codes on the diagnostic scanner that can cause the engine to shut down.

A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, or a misfire while in gear. If you experience any of these issues it is likely your sensor is failing and should be replaced. They're cheap and easy to find, especially when they're a Bosch model like ours. You can also choose the GM version of this component is also a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the reason behind a slew of issues with your car. It is a crucial part of your audi tt key replacement's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is turning. When this sensor fails, it will cause problems for the transmission as well as the rest of the car's components.

The G5 engine speed sensor is located on the outside of the transmission just above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU utilizes this signal to regulate the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, 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. You should observe approximately 1000 ohms of resistance between those points. This is a common part across the audi a3 key replacement 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.