How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the edge of transmission just above the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49) which is then sent 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. The sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must know 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 the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync, 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).
It is a little tricky to test because there are several pins on the connector, and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is in full operation. Check for signs of coolant, or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll i had massive power loss as if the engine was running out of gas or the injectors are not firing at all. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. I put a piece of tissue over each injector hole and when I start the engine with no sparks, the 3 with gazoline jump out. The fourth one remains shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. I'm assuming that the issue is elsewhere.
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 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows a temperature of -49c. Also, i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, i feel i have pretty much ruled out everything else. But i'm worried that I might have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is identical 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 click here or parts store. Testing them is easy - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines needs to be aware of the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine here Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you are in gear. It is likely that your sensor is failing and requires to be replaced if you experience get more info any of these symptoms. They're inexpensive and easy to locate particularly when they're a Bosch unit like ours. You can replacement audi car key also choose the GM version of this unit is also a good option.
5. Tachometer
A faulty engine speed sensor could be the cause of numerous issues in your car. It's an essential component of the transmission in your Audi since it sends information to the ECU about how fast or slow the engine is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear click here and sends 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 and then sends it on to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also 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. You should detect an average resistance of 1000 ohms between these points. This is a common part that is found across the Audi 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.