How to Replace an audi etron key G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/Land-Rover.png)1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, above the flywheel ring. The sensor transmits 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 indicator to the G5 Tachometer within the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and audi tt key replacement could indicate the chain stretching or a jump link on the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult because there are two connector pins, and they serve different purposes but the best method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is at full operation. Examine for signs of coolant or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced massive power loss like the engine is out of gas or injectors aren't firing anymore. I took out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was dry. When i crank the engine, there are no sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th stay shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got zero ohm. I assume that the problem is in another location.
I also tried to reset the PID but without success. The car will start if the G28 is unplugged and it runs perfectly when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, as i believe that i've completely ruled out all other possibilities. But i'm worried that I may have missed something. If anyone has any ideas please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or in a local parts store. It is easy to test them - just put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to know 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 either of these goes bad you will get codes on the diagnostic scanner which can cause the engine to shut down.
A failing G28 sensor can cause an inaccurate speed counter key for audi the gearbox or a gearbox that shifts faster than normal, or an unfire when in the gear. If you are experiencing any of these issues, it is likely that your sensor is deteriorating and should be replaced. The good thing is that they are very affordable and easily accessible particularly if you're looking at an Bosch model, which is what we have. If you prefer, GM's version of this component is an option.
5. Tachometer
A damaged engine sensor could cause a number of problems within your vehicle. It's a crucial component of the transmission of your Audi keys replacement cost since it sends information to the ECU on how fast or slowly the engine is turning. If this sensor fails, it can disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU then uses and processes this signal to control fuel, timig, and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Also, you can examine the continuity between pins 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. It should show approximately 1000 ohms of resistance between those two pins. This is a common feature across the audi replacement key 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/11/happy-african-american-businessman-holding-car-key-2022-12-16-16-36-17-utc-min-scaled.jpg)
