How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU via the grey wire (T55/49) and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC, and the location of the camshaft to trigger the spark and injectors.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of a chain stretch or a jumpy chain link in the upper chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two connector pins and they perform different functions but the most effective method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when it is operating at its maximum. If you are having problems with this component, look for signs of oil or coolant in the connector bay.
2. audi a3 key replacement near me , when accelerating from highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine had run out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs. Three were drenched in gazoline, the 4th one was dry. I put a piece of tissue over each injector hole and when I start the engine without sparks, the three with gazoline jump out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c, even if I unplug it. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.
audi a4 key replacement 'm not sure what to do, i feel i have pretty much eliminated everything else. But i am afraid i might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style sensor is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. It is easy to test them - just switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make a decision about fuel injector timing etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner that can cause the engine to shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, and/or an unfire when in the gear. If you are experiencing any of these problems, it is likely your sensor is going bad and should be replaced. The good news is they are very cheap and easy to find, especially in the case of the Bosch model, like ours. Alternately, GM's version this component is a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many problems in your car. It's an essential component of your Audi's transmission, because it communicates to the ECU about how fast or slow the car's crankshaft is turning. If this sensor fails, it will cause problems for the transmission and the rest of the car's components.
The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer in instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This is a typical component across the Audi 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.