How to Replace an audi key fob replacement G28 Engine Speed Sensor
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/woman-showing-the-car-keys-2022-12-16-22-09-32-utc-min-scaled.jpg)Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, just above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU uses this information to regulate boost and fuel. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors in the right way.
If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper timing chain. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult because there are two pins for the connector and they have different functions but the best way to test it is to measure the resistance between the sensor and the ECU. If the sensor is operational, it should be reading approximately 1000 ohms. If you're having issues with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had a big cut in power like the engine is running out of gas or injectors aren't firing any more. In the morning, i removed the spark plugs. Three were drenched with gazoline the 4th one was dry. When I start the engine, there are no sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline jump out but the 4th stay shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero Ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it works fine when the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much ruled everything else out. I'm afraid i may have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or a parts store. It is simple to test them to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must know the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.
A damaged G28 sensor can cause an inaccurate speed counter for the gearbox and a gearbox which shifts faster than normal, and/or an unfire when in the gear. It is probable that the sensor is failing and requires to be replaced if you notice any of these signs. They're cheap and easy to find particularly if they're an Bosch unit like ours. Alternately, the GM version of this component is also a good choice.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues within your vehicle. It's an essential component of the audi tt key fob's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It sends a signal via gray wire to ECU pin T55/49. The ECU uses this signal to control the flow of fuel and boost and also to timigrate. It also transmits it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, 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 and pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is a standard part that is found across the replacement audi keys audi a3 keys a3 key, a cool way to improve, 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.