How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge, above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to control boost and fuel. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is out of alignment with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper chain. However, the error 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 pins on the connector and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is functional, it should read around 1000 ohms. If you're having issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing anymore. This morning i pull out the spark plugs, three were drenched with gazoline the 4th one was dry. When I start the engine with no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline pop out, but the 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero Ohm. I assume that the problem is in another location.
I also tried to reset the PID with no success. The car can start if the G28 is not plugged in and is running fine when it is connected but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. Also, i noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when i rev the engine.
I'm not certain what to do, i think i've pretty much ruled out everything else. But i'm worried that i might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. It is simple to test them - simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these, the diagnostic scanner will display codes that could cause the engine shutting down.
A malfunctioning G28 sensor can cause an inaccurate speed counter for your gearbox and a gearbox which shifts faster than normal, and/or a misfire while in the gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these signs. They are cheap and easy-to-find especially in the case of an Bosch model like ours. Alternately, the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues in your car. It's a crucial component of the transmission in your Audi since it sends information to the ECU on how fast or slow the engine of the car is spinning. When this sensor fails, it could disrupt the performance of the transmission as well as the other car's components.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU uses this signal to control the amount of fuel and boost, and also to timigrate. audi lost key replacement transmits it to the G5 Tachometer inside the instrument cluster. audi q7 keys locked in car can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also verify continuity between pin 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 see around 1000 ohms of resistance between these two points. This part is common across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 Du You may also find good ones in wrecking yards.