How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It sends a signal to the ECU via the grey wire (T55/49), then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated 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 flow of fuel, timig and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC and also the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper timing chain. However, the 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 they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when it is at full operation. Look for evidence of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a massive reduction in power. It was like the engine had run out of gas. Or my injectors weren't firing. Today, i pulled out the spark plugs, 3 were drenched with gazoline the fourth one 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 that have gazoline pop right out. The fourth one remains shut. I tested the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. I assume that the problem is elsewhere.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure get more info is zero.
I'm not sure what to do. I feel like i've pretty much ruled everything else out. But i'm worried that I may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals 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 parts store. It is simple to test them read more - just switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know both the position and speed of the crankshaft in get more info order to make a decision about timing of the fuel injector, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem here with either one of these, the diagnostic scanner will display codes that could lead to an engine shutdown.
A malfunctioning G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, and/or a misfire in the gear. It is possible that your sensor is failing and needs to be replaced if you encounter any of these symptoms. The good thing is that they are very affordable and easily accessible, especially if you're looking at an Bosch sensor, like ours. Alternatively, the GM version read more of this component is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues in your car. It is an important part of the transmission of your Audi because it relays information to the ECU regarding how fast or slowly 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 outside of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 through an uncolored wire. The ECU then uses and processes this signal to control the flow of fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can check 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. You should see an average resistance of 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 Du You may also find some good ones in wrecking yards.