The 10 Most Scariest Things About Audi G28

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How to Replace an audi q3 key G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge over the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU uses this information to regulate fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.

If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate the chain stretching or a jump link on the upper chain of timing. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

Testing is a bit challenging because there are two pins for the connector and they serve different purposes but the most effective way to test it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading approximately 1000 ohms. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a significant decrease in power. It was like the engine had run out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I put a piece of tissue over each hole in the injector and when i start the engine with no sparks, the three with gazoline jump out. The 4th one remains closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. Therefore, i think the issue is somewhere else.

I also tried to reset PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do. I think 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 in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and audi Keys both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. Testing them is easy by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and audi tt key case ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes bad you will get codes on the diagnostic scanner that can lead to engine shutdown.

A failing G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire while in the gear. It is likely that your sensor is failing and needs to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate, especially when they're an Bosch model like ours. If you prefer, GM's version of this part is an excellent choice.

5. Tachometer

A malfunctioning engine speed sensor could be a cause for many issues in your vehicle. It's a vital component of your audi a3 key fob's transmission, Audi Remote Key as it sends information to the ECU about how the car's crankshaft is turning. If this sensor fails, it can disrupt the performance of the transmission and the other car's components.

The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can check for sensor 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 [79trace [79]), and between pin T6a/1 and pin T26a/12. You should observe approximately 1000 ohms resistance between those two pins. This is a typical component across the Audi Key Fob 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.