Why Nobody Cares About Audi G28

How to Replace an audi etron key q7 key (king-wifi.win said) G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is situated on the edge of the transmission above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via an uncolored wire. The ECU utilizes this information to control fuel and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.

The sensor serves as a reference for comparing 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 activate spark and injectors in the right way.

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

It is a little tricky to test since there are several connector pins, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read around 1000 ohms. Look for signs of coolant, or oil in the connector bay if there are problems with this part.

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 are not firing anymore. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. When i crank the engine without sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stay shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. So i assume the problem is elsewhere.

I also tried to reset the PID without success. The car can start if the G28 is unplugged and is running fine when it is connected but it still has the intermittent misfire issue at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I'm not sure what to do, as i feel i have pretty much completely ruled out all other possibilities. But i'm worried that I may have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style sender is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. It is simple to test them: simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). 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 regarding timing of the fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go wrong, you will receive codes on the diagnostic scanner which could cause engine shut down.

Some of the signs of a failing G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or misfiring when in gear. If you are experiencing any of these issues it is likely that your sensor is failing and requires replacement. The good news is they are very affordable and readily available particularly in the case of the Bosch model, which is what we have. If you prefer, GM's version of this part is an option.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems in your vehicle. It's an essential component of the transmission in your audi smart key replacement because it relays information to the ECU regarding how fast or slowly the engine of the car is turning. If the sensor fails, it could affect the performance of the transmission as well as the other car's components.

The G5 engine speed sensor is located at the edge of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see a resistance of approximately 1000 ohms between these points. This part is common across the audi a1 key 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du You may also find some good ones in wrecking yards.