• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

How to Replace an audi tt key fob G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 through 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 within the instrument cluster.

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

If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and could indicate chain stretch or a jumped link on the upper timing chain. However, the error code won't be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging since there are two connector pins and they serve different purposes however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is in full operation. If you're experiencing issues with this component, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed I noticed a massive reduction 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, 3 were soaked with gasoline and the 4th was dry. When i crank the engine with no sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stays closed. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero ohm. I'm assuming the issue is elsewhere.

I also tried to reset the PID with no success. The car can start if the G28 is disconnected and runs fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, but i think i've pretty much completely ruled out all other possibilities. I'm concerned that i may have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal 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. You can easily find the spare in a salvage shop or parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines requires to know the position and speed of the crankshaft to determine fuel injector timing, etc. To do this, cheapest it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, replacement Audi A3 key the diagnostic scanner will display codes that could lead to an engine shut down.

A malfunctioning G28 sensor can cause an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, and/or a misfire while in the gear. It is likely that your sensor is failing and requires to be replaced if you notice any of these symptoms. The good news is that they are very affordable and easy to find particularly when you're looking at the Bosch model, which is what ours are. Alternately, the GM version of this component is also a good option.

5. Tachometer

A faulty engine speed sensor could be the reason behind a slew of issues in your car. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. If this sensor fails, it will affect the performance of the transmission and the rest of the car's components.

The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU is then able to process this signal to control the flow of fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) and Audi A3 Spare Key between pin T6a/1 and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms between these points. This is a typical component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.