How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) and then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain stretching or a jump link on the upper chain of timing. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test since there are various connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading around 1000 ohms. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors aren't firing at all. Today, i pulled out the spark plugs, 3 were drenched with gazoline the 4th one was dry. I put a piece of tissue over each injector hole, and when i turn the engine on without sparks, the ones that have gazoline pop right out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. I'm assuming the issue is in another place.
I also tried to reset PID but without success. The car is able to start if the G28 is unplugged and is running fine when it is connected but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.
I don't know what to do. I feel like i've pretty much ruled everything else out. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of 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. You can easily find an extra in a wrecking shop or a parts store. Test them out by putting your DMM in resistance mode and measure between pins 1 (with the bump on the new audi key connector end up) and 2 (2nd from left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed of the crankshaft to determine fuel injector timing, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either one of these, the diagnostic scanner will show the codes that could trigger an engine shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts more quickly than normal, or a misfire while in gear. It is possible that your sensor is failing and needs audi a1 car key to be replaced if you encounter any of these symptoms. The good news is they are quite affordable and easily accessible particularly if you're looking at a Bosch unit which is what ours website are. You can also choose the GM version of this part is also a good choice.
5. Tachometer
A damaged engine sensor spare audi key cost could cause a number of problems within your vehicle. It is an important part of the transmission in your Audi since it sends information to the ECU on how fast or slowly the engine is turning. If the sensor fails, it could cause problems for the transmission, as well as the other car's components.
The G5 engine speed sensor is located on the edge 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 uses this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer inside the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 website (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. It should show around 1000 ohms of resistance between these two points. This is a typical component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.