• 목록
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

How to Replace an audi key blade G28 Engine Speed Sensor

In this video Charles the humble mechanic demonstrates 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 through the grey wire T55/49 and then to the tachometer in 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 a signal to ECU pin T55/49 using an uncolored wire. The ECU uses this information to control the amount of fuel and boost. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC, and the position of the camshaft, in order to activate the spark and injectors.

If this sensor fails when it fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumpy chain link in the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test since there are various pins on the connector 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 about 1000 ohms when it is at full operation. Look replacement key for audi signs of coolant or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was unclean. When I start the engine with no sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got zero ohm. I'm assuming that the issue is in another location.

I also tried to reset the PID but with no luck. The car can start if the G28 is unplugged and is running fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar while 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 ruled everything else out. But i am afraid I may have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare audi key in a wrecking shop or parts store. Testing them is easy - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that needs to know the position and speed of the crankshaft to make a decision about fuel injector timing etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these sensors go badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.

A failing G28 sensor could cause an inaccurate gearbox speed counter and a gearbox which shifts more quickly than normal, or a misfire in the gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these symptoms. They're cheap and easy to find, especially when they're an Bosch model like ours. Alternately, GM's version this component is a good option.

5. Tachometer

A faulty engine speed sensor could be the reason behind a slew of issues with your car. It's a crucial component of the transmission in your audi advance key, as it transmits information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor can cause the transmission to malfunction and other components of the car to be affected.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU utilizes this signal to regulate the flow of fuel and boost and also timig. It also sends 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. You can also 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. You should observe around 1000 ohms of resistance between these two points. This is a typical component across the Audi Q7 Key 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.