How to Replace an audi a3 key fob G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49), then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC, and the location of the camshaft 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 not in sync and possibly indicating the chain stretching or a jump link on the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/skoda-logo.jpg)It's a bit tricky to test as there are different pins on the connector, and they all have different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is at full operation. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
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 the injectors are not firing anymore. In my area the morning, i removed the spark plugs, three were drenched with gazoline the fourth was dry. I put a piece of tissue over each injector hole and when i start the engine with no sparks, the three with gazoline jump out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I'm assuming the issue is in another place.
I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.
I'm not sure what to do. I believe that I've ruled everything else out. However, i'm afraid that I might have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sensor is the same as the G4 and both function in the 80, 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or at a parts store. It is simple to test them - simply 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
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to be aware of the speed and position of the crankshaft to make decisions about fuel injector timing 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 could cause engine shut down.
Some of the symptoms of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox the gears are shifting faster than normal and/or a misfire when in gear. If you have any of these problems, it is likely your sensor is going bad and should be replaced. They're inexpensive and easy to locate, especially if they're an Bosch model like ours. Alternately, GM's version this component is a good option.
5. Tachometer
A failing engine sensor could cause a myriad of issues in your car key replacement audi. It's an essential component of the transmission of your audi a4 replacement key since it sends information to the ECU on how fast or slowly the engine of the car is spinning. If the sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU then uses and processes the signal to control fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This is a standard part that is found across the audi key replacement cost uk 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.