How to Replace an audi spare key key fob replacement cost (Read the Full Article) G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated at the top of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor is used as a reference point to connect 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 trigger spark and injectors in the right way.

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

It's a bit tricky to test since there are different connector pins, and each one has 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 it is in full operation. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a significant drop in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the 4th was dry. When i crank the engine without sparks, I put a piece of tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th one stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming that the issue is somewhere else.

I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, as i feel i have pretty much completely ruled out all other possibilities. However, i'm afraid that I might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80 100, 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. It is simple to test them - put 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 end). They should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines requires to know the position and speed the crankshaft in order to make a decision about timing of the fuel injector, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could lead to an engine shutdown.

A failing G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, or a misfire while in gear. If you have any of these issues it is most likely that your sensor is deteriorating and requires replacement audi key cost. They're inexpensive and easy to locate especially in the case of a Bosch unit like ours. Alternately, the GM version of this part is also a great option.

5. Tachometer

A failing engine speed sensor could be the cause of a slew of problems in your vehicle. It's an essential component of the transmission in your Audi because it relays information to the ECU regarding how fast or slow the engine is spinning. If this sensor fails, it can affect the performance of the transmission as well as the other car's components.

The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer, between the 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. It should show around 1000 ohms of resistance between those two pins. This is a standard part that is found across the audi new key 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.