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 situated on the edge of the transmission above the flywheel ring 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, above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors accordingly.
If this sensor fails the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
It is a little tricky to test because there are different 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. When the sensor is operational, it should read about 1000 ohms. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had an abrupt drop in power like the engine is running out of gas or injectors are not firing any more. I took out the spark plugs this morning, 3 were soaked with gasoline and the fourth was dry. I placed a tissue over each injector hole, and when i start the engine without sparks, the ones that have gazoline pop right out. The 4th one remains closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming the issue is in another place.
I also tried to reset the PID without success. The car will start when the G28 is unplugged and runs fine when it is plugged in but it still has the intermittent misfire issue 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 read more bar but the actual pressure is zero.
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 might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style sender is the same as the G4 and they both work replacement audi car key 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 determine the distance between pins 1 and 2 (with the bump at the audi replacement key connector's end facing upwards). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must be aware of the position and speed of the crankshaft to determine fuel injector timing, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 get more info to accomplish this. If you are experiencing issues with either of these sensors, the diagnostic scanner will display codes that could lead to an engine shut down.
A malfunctioning G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or an unfire when in the gear. If you experience any of these problems, it is likely your sensor is failing and needs replacing. The good thing is that they are very cheap and easily accessible particularly when you're looking at the Bosch unit which is what we have. Alternatively, GM's version of this component is an excellent choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind a slew of issues in your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine sensor is located at the edge audi a3 key replacement near me of the transmission, over the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig, and boost, and also transmitting it 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 [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these points. This is a standard component across the Audi 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.