How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you 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 an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, just above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of an issue with the chain or a jump in the chain link of the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit challenging as there are two different pins for the connector and they serve different purposes but the most effective method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is functional, it should read approximately 1000 ohms. Examine for signs of coolant, or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge drop in power. audi key replacement was as if the engine had run out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs, three were drenched with gazoline the fourth was dry. I put a piece of tissue over each injector hole and when I start the engine with no sparks, the ones with gazoline jump out. The fourth one remains shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. So i assume the problem is somewhere else.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I'm not certain what to do, as i believe that i've eliminated everything else. But i'm worried that I may have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. audi a5 replacement key -style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is easy to test them - simply put your DMM into resistance mode and determine 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 in our 20vt turbo (3B AAN ABY) engines needs to know both the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could lead to an engine shut down.
Some of the symptoms of a malfunctioning G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal and/or a misfire when you are in gear. If you have any of these problems, it is likely that your sensor is deteriorating and requires replacement. They're cheap and easy to find, especially if they're a Bosch model like ours. audi key replacement can also choose the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues within your vehicle. It's a vital component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor could cause the transmission to fail and other components in the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Also, you can verify 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. You should observe approximately 1000 ohms of resistance between those two pins. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU, so you might find them in wrecking yards.