How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is situated at the top of the transmission, above the flywheel ring gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate boost and fuel. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor serves as a reference for comparing 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 start spark and injectors accordingly.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of sync with the Intake Camshaft. genuine audi key replacement could also indicate an issue with the chain or a jumped chain link in the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test since there are various pins on the connector and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is functional, it should read about 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 from the highway paytoll at a high speed I noticed a significant decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. I took out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. I put a piece of tissue over each hole in the injector and when i turn the engine on without sparks, the ones with gazoline jump right out. My Web Site closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got 0ohm. So i assume the problem is somewhere else.
I also tried to reset the PID with no success. audi replacement car keys will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 when i rev the engine.
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 suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent from 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. It is easy to find a spare in a wrecking shop or a parts store. It is easy to test them - simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must know the position and speed of the crankshaft to make decisions about timing of the fuel injectors, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger an engine shutdown.
The signs of a malfunctioning G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you're in gear. It is probable that your sensor is failing and needs to be replaced if you notice any of these symptoms. The good thing is that they are very cheap and readily available, especially if you're looking at the Bosch sensor, which is what ours are. You can also choose the GM version of this unit is also a great option.
5. Tachometer
A failing engine sensor could cause a variety of issues in your car. It is a crucial part of the 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 malfunction and other components of the car to be affected.
The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to regulate fuel and boost, as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This part is common across the Audi 80-100-200-RS2 model, ranging beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU You may also find good ones in wrecking yards.