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 on the outside of the transmission, above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49), then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via the grey wire. The ECU utilizes this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.
If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate an issue with the chain or a jumpy chain link in the upper chain of timing. However the code will not appear on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test since there are several connector pins, and each has its own functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when it is operating at its maximum. Look for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant drop in power. It was like the engine had run out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was unclean. When i crank the engine with no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline pop out, but the 4th stay closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero Ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID without success. The car will start if the G28 is unplugged get more info and it runs perfectly when it is plugged in but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62) even when unplugged, still shows temperatures of -49c. I also advanced key audi noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.
I'm not certain what to do, but i feel i have pretty much completely ruled out all other possibilities. But i'm worried that I might have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The get more info GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. It is simple to test them - simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed of the here crankshaft to determine fuel injector timing, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes bad you will get codes on the diagnostic scanner that could cause engine shut down.
A failing G28 sensor can cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, or a misfire in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of these symptoms. They are cheap and easy-to-find, especially if they're an Bosch sensor like ours. Alternatively, the GM version of this component is also a good option.
5. Tachometer
A faulty engine speed sensor could be the reason behind numerous problems in your vehicle. It is an important part of the transmission in your website Audi, as it transmits information to the ECU on how fast or slow the engine is spinning. When this sensor fails, it can cause problems for the transmission and the other car's components.
The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49, via a grey wire. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also relays it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a typical component across the Audi 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.