How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located at the top 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 within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test because there are various pins on the connector and each has its own functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should be reading around 1000 ohms. Check for evidence of coolant or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced massive power loss as if the engine was running out of gas or injectors aren't firing any more. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. I put tissue over each hole in the injector and when i start the engine without sparks, the three that have gazoline pop right out. The 4th one remains shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the website PID without success. The car is able to start when 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 if it is not plugged in, shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I don't know what to do. I feel like i've pretty much all other possibilities out. I'm concerned that i may have missed something. If anyone has any new audi car key ideas please chime in! 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 and both are used in the 80 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or at 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 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 to make decisions about timing of the fuel injectors, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will show codes that could lead to an engine shutdown.
A malfunctioning G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, and/or a misfire in gear. It is probable that your sensor is failing and needs to be replaced if you encounter any of these symptoms. The good thing is that they are quite affordable and easy to find particularly when you're looking at the Bosch sensor, which is what ours are. Alternatively, the GM version of this component is also a good replacement key for audi a4 choice.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your vehicle. It's an essential component of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is rotating. When this sensor fails, it will affect the performance of the transmission, as well as the other car's components.
The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU then uses and processes the signal to control fuel, timig, and boost as audi a4 key replacement well as transmitting it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by audi car keys replacement examining the continuity of the sensor to the tachometer. Additionally, you can 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 as well as pin T26a/12. There should be the resistance to be around 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du, so you might find them in wrecking yards.