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How To Beat Your Boss On Audi G28
How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located at the edge of transmission, above the flywheel gear. It transmits a signal 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 the G28 Engine Speed Sensor sends signals to ECU pin T55/49 through a grey wire. The ECU utilizes this information to control boost and fuel. It also sends a signal to the G5 tachometer in the instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors in the right way.

If this sensor fails, 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 be a sign of a chain stretch or a jumpy chain link in the upper chain of timing. replacement audi key cost uk The Key Lab won't appear without the additional information supplied by other sensors (G4 or G40).

Testing is a bit tricky since there are two connector pins and they perform different functions but the most effective method to test it is to measure resistance between the sensor and the ECU. It should read around 1000 ohms when it is in full operation. Examine for signs of coolant, or oil in the connector bay if there are problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll i had massive power loss like the engine is running out of gas or the injectors are not firing any more. I took out the spark plugs this morning, 3 were soaked with gasoline and the fourth was unclean. I placed a tissue over each injector hole, and when I start the engine with no sparks, the ones that have gazoline pop right out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. Therefore, i think the issue is in another place.

I also tried to reset PID without success. The car can start when the G28 is not plugged in and it runs perfectly when it is plugged in but it still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.


I'm not certain what to do, but i believe that i've eliminated everything else. I'm worried that i might have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80, 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or in a local parts store. It is simple to test them - simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines needs to know both the speed and position of the crankshaft in order to make a decision about timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go badly, you will see codes on the diagnostic scanner that can lead to engine shutdown.

A failing G28 sensor could cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, and/or an unfire when in gear. It is possible 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 in the case of an Bosch sensor like ours. Alternatively, the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your car. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it will affect the performance of the transmission as well as the rest of the car's components.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU is then able to process the signal to control the flow of fuel, timig and boost and then transmitting it to the G5 tachometer inside 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 on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. There should be the resistance to be around 1000 ohms in these areas. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 Du You may also find some good ones in wrecking yards.

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