How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located near the transmission's edge over the flywheel gear. It transmits a signal 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 an electrical signal to ECU pin T55/49 via a grey wire. advanced key audi uses this information to regulate fuel and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors accordingly.
If this sensor fails to function, the ECU will display a P00160 error message. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test as there are several pins on the connector, and they all have different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is fully operational, it should read approximately 1000 ohms. If you're having issues with this component, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant reduction in power. It was as if the engine had run out of gas. Or, my injectors were not firing. In the morning, i removed the spark plugs, 3 were soaked with gazoline and the fourth one was dry. I put a piece of tissue over each injector hole and when i start the engine without sparks, the 3 with gazoline jump right out. The fourth one remains shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming that the issue is in another location.
I also tried to reset PID but without success. The car will start if the G28 is not plugged in and it runs perfectly when it is connected but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice 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 sure what to do, as i believe that i've ruled out everything else. I'm afraid i may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is easy to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.
4. audi car keys replacement of our 20vt turbo (3B AAN ABY) engines must be aware of the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will show codes that could lead to an engine shutdown.
A damaged G28 sensor can cause an inaccurate gearbox speed counter and a gearbox which shifts more quickly than normal, and/or a misfire in gear. If you experience any of these issues it is likely that your sensor is going bad and requires replacement. They are cheap and easy-to-find especially when they're a Bosch model like ours. If you prefer, GM's version of this part would be an excellent choice.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems in your vehicle. It's a crucial component of the transmission of your Audi since it sends information to the ECU on how fast or slowly the engine is turning. If the sensor fails, it could affect the performance of the transmission and the other car's components.
The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms between these points. This is a standard component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.