20 Myths About Audi G28: Busted

How to Replace an audi smart key replacement G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU through an uncolored wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the transmission, directly above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends a signal to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware 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 to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper chain of timing. However the code will not appear on its own, without additional information from other sensors (G4 and G40).

It's a bit tricky to test as there are different pins on the connector, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. Look for signs of coolant, or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant drop in power. It was as if the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. I put a piece of tissue over each hole in the injector and when I start the engine without sparks, the ones with gazoline jump out. The 4th one stays closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. I'm assuming that the issue is elsewhere.

I also tried to reset the PID without success. The car can start if the G28 is not plugged in and is running fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.

I'm not sure what to do. I feel like i've pretty much ruled everything else out. But i am afraid i might have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style sensor is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a junkyard or at a parts store. Testing them is easy to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either one of these, the diagnostic scanner will display the codes that could trigger an engine shut down.

Some of the symptoms of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox and gears that shift faster than normal and/or misfiring when you are in gear. If you have any of these issues it is most likely that your sensor is going bad and should be replaced. The good news is they are very cheap and easy to find particularly when you're looking at the Bosch model, which is what ours are. Alternatively, the GM version of this component is also a great option.

5. Tachometer

A failing engine speed sensor could be a cause for a slew of issues in your vehicle. It's an essential component of the audi keys replacement cost key fob not working (throatclef6.werite.net)'s transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor could cause the transmission to malfunction and other car components to be affected.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits a signal via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can check continuity between pin 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 detect the resistance to be around 1000 ohms between these two points. This is a typical part across the audi key shell 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.