Why Nobody Cares About Audi G28

How to Replace an audi a1 key G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer 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 a signal to ECU pin T55/49 using a grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC, and the position of the camshaft, so that it can activate the spark and injectors.

If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit challenging since there are two connector pins and they serve different purposes but the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is functional, it should read around 1000 ohms. If you are having problems with this component, look for signs of oil or coolant in the connector Cost Of Audi Key Replacement bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a massive decrease in power. It was as if the engine had run out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs, 3 were drenched with gazoline the fourth was dry. When I crank the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline leap out, however the 4th stay shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I think the issue is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged and it runs perfectly when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do, as i think i've pretty much eliminated everything else. I'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal by 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 at a 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 on the connector's edge facing upwards). They must be infinite ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner which can lead to engine shutdown.

A failing G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, and/or a misfire while in gear. If you experience any of these issues, it is likely your sensor is going bad and needs replacing. The good thing is that they are very affordable and easy to find, especially when you're looking at a Bosch unit like ours. If you prefer, GM's version of this component is a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of numerous problems in your car. It's an essential component of your audi keyless entry's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is turning. When this sensor fails, it will disrupt the performance of the transmission as well as the other audi car key cover's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends an electrical signal through gray wire to ECU pin T55/49. 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 test the sensor for failure by examining the 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 [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these points. This is a standard part that is found across the audi keys replacement cost 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.