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. This sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, above the flywheel ring. The sensor sends signals 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 in instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain is stretched or a jump link on the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging because there are two connector pins, and they perform different functions but the best method of testing it is to measure the resistance between the sensor and the ECU. When the sensor is operational, it should be reading about 1000 ohms. If you're having issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced massive power loss like the engine is out of gas or injectors are not firing anymore. In the morning, i removed the spark plugs, three were drenched in gazoline, the 4th one was dry. I placed a tissue over each hole in the injector and when i start the engine without sparks, the 3 with gazoline jump right out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero Ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID with no success. The car can start if the G28 is unplugged and is running fine when it is connected however it has intermittent misfire issues 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 while the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much all other check here possibilities out. However, i'm afraid that I may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter is the same as the G4 and both are used in website the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. Test them out to do - just put your click here DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black end of the connector). They must be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must be aware of the position and audi a1 key replacement speed of the crankshaft to make decisions regarding fuel injector timing, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will show codes that could cause an engine shutdown.
Some of the symptoms of a failed G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or a misfire when in gear. If you experience any of these issues it is most likely that your sensor is deteriorating and requires replacement. The good thing is that they are very affordable and readily available particularly if you're looking at a Bosch model, which is what we have. You can also choose the GM version of this part is also a good choice.
5. Tachometer
A faulty engine speed sensor could be a cause for a slew of problems in your vehicle. It is an important part of the transmission of your Audi because it relays information to the ECU on how fast or slow the engine of the car is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located at here the outskirts of transmission, above the flywheel ring. It transmits a signal via gray wire to ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is the same across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find some good ones in wrecking yards.