How to Replace an Audi Key Shell G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located near the edges of the transmission, above the flywheel ring 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

It is located on the outside of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 through an uncolored wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used to correlate the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and the location of the camshaft so that it can activate the spark and injectors.

If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate a chain stretch or a jump in the chain link of the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky as there are two different connector pins and they have different functions however the best way to test it is to measure resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is in full operation. Check for evidence of coolant or oil in the connector bay if you are experiencing issues with this component.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced an abrupt drop in power like the engine is out of gas or injectors aren't firing at all. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th one stays shut. I tried to test the ground connections 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 but with no luck. The car will start if the G28 is not plugged in and runs fine when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.

I'm not sure what to do, i feel i have pretty much ruled out everything else. But i'm worried that I may have missed something. Please let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. It is simple to test them: simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to be aware of the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shutdown.

Some of the symptoms of a failing G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you're in gear. It is possible that the sensor is failing and needs to be replaced if you notice any of these signs. They're cheap and easy to find particularly when they're an Bosch model like ours. Alternately, the GM version of this component is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your car. It's a vital component of the audi tt key's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor can cause the transmission to malfunction and other car components to be affected.

The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, audi car key replacement cost connect key (Technetbloggers blog post) via a grey wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also relays it to the G5 Tachometer in instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can verify 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 an average resistance of 1000 ohms between these two points. This is a common feature across the audi a5 key fob 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du, so you might find good ones in wrecking yards.