Audi G28: 10 Things I d Like To Have Learned Earlier

How to Replace an audi key fob not working G28 Engine Speed Sensor

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

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control the amount of fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.

If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of 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 chain of timing. 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 way to do it is by measuring the resistance between the ECU and the sensor. It should read approximately 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 experienced massive power loss as if the engine was running out of gas or injectors are not firing any more. This morning i pull out the spark plugs, 3 were drenched with gazoline the fourth one was dry. I put a piece of tissue over each hole in the injector and when I turn the engine on without sparks, the ones with gazoline jump out. The fourth one remains shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However, the intermittent misfire problem continues to occur at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do, as i feel i have pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is simple to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed the crankshaft in order to make a decision about 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 sensors go bad you will get codes on the diagnostic scanner which can lead to engine shutdown.

Some of the signs of a malfunctioning G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal, and/or a misfire when in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these symptoms. They're cheap and easy to find particularly in the case of a Bosch unit like ours. You can also choose the GM version of this component is also a good option.

5. Tachometer

A failing engine speed sensor could be the reason behind numerous issues in your vehicle. It is a crucial part of the audi key copy's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine speed sensor is located at 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 is then able to process the signal to control the flow of fuel, timig and boost, and also sends it on to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also 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 two pins. This is a common feature across the audi a3 key replacement remote Key (dsred.com) 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU So, you may find good ones in wrecking yards.