How to Replace an spare audi key G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission, above the flywheel gear. It sends a message to the ECU via 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 the G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer within the instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC and also where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain stretching or a jump link on the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).

It is a little tricky to test because there are various connector pins, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is operating at its maximum. Examine for signs of coolant, or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is out of gas or injectors are not firing at all. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. I placed a tissue over each injector hole and when i turn the engine on without sparks, the ones with gazoline jump right out. The 4th one remains shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. Therefore, i think the issue is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I'm not certain what to do, as i believe that i've completely ruled out all other possibilities. However, i'm afraid that i might have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or in a local parts store. It is easy 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 end facing upwards). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines must be aware of the speed and position of the crankshaft to determine fuel injector timing, etc. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner that can lead to engine shutdown.

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

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It's a vital component of the audi car Key replacement cost's transmission because it communicates to the ECU about how the car's crankshaft is turning. If the sensor fails, it can cause problems for the transmission and the other car's components.

The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU uses this signal to regulate the flow of fuel and boost and also timig. It also transmits it to the G5 Tachometer in instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Additionally, 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. It should show approximately 1000 ohms resistance between those points. This is a typical part that is found across the replacement audi key cost uk 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.