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How to Replace an replacement audi a4 key G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is situated at the top of the transmission just above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via an uncolored wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.

The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.

If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or 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 by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is operating at its maximum. If you are having problems with this sensor, look for signs of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll i had an abrupt drop in power as if the engine was running out of gas or the injectors are not firing anymore. I took out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. When I crank the engine, there are no sparks, I put a piece of tissue on top of each injector hole and the 3 drenched with gazoline pop out, but the 4th stays shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming that the issue is in another location.

I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.

I'm not sure what to do. I feel like i've pretty much all other possibilities out. But i'm worried that I might have missed something. If anyone has any suggestions, please share them! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. It is simple to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft to make a decision about fuel injector timing etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these, the diagnostic scanner will show the codes that could trigger an engine shutdown.

A malfunctioning G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts more quickly than normal, or an unfire when in gear. It is likely that the sensor is failing and needs to be replaced if you encounter any of these symptoms. They're inexpensive and easy to locate particularly in the case of a Bosch model like ours. Alternately, the GM version of this unit is also a great option.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems within your vehicle. It is a crucial part of the audi key programming's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components in the car key replacement audi to be affected.

The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 via an uncolored wire. The ECU then processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of 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 [79]), and between pin T6a/1 and pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This part is common across the spare audi key 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du You may also find some good ones in wrecking yards.