How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is situated at the top of the transmission just 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 located at the edges of the transmission, just above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends a signal to the G5 tachometer in the instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and where the camshaft lies in order to activate the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper chain. The code won't show without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky because there are two pins for the connector and they serve different purposes however the best method of testing it is to measure the resistance between the sensor and the ECU. It should read approximately 1000 ohms if the sensor is at full operation. If you're experiencing issues with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power like the engine is running out of gas or the injectors are not firing any more. I pulled 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 that have gazoline pop right out. The fourth one remains closed. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. I assume that 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 runs fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do, i feel i have pretty much completely ruled out all other possibilities. But i'm worried that I might have missed something. more info If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or at 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 must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B audi a1 keys AAN ABY ADU) engines must be aware of the speed and position of the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either one of these, the diagnostic scanner will show codes that could cause an engine shutdown.
A failing G28 sensor could cause an inaccurate speed counter audi spare keys for the gearbox, a gearbox that shifts more quickly than normal, and/or an unfire when in gear. If you are experiencing any of these issues it is most likely that your sensor is going bad and should be replaced. The good news is they are very affordable and easy to find particularly in the case of an Bosch sensor, which is what ours are. If you prefer, GM's version of this part is an excellent choice.
5. Tachometer
A failing engine speed sensor could be the reason behind numerous issues with your car. It's a vital component of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 engine speed sensor is located at the edge of how to open audi car key the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to regulate fuel and boost, and also timig. It also sends it to the G5 Tachometer located 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. There should be the resistance to be around 1000 ohms between these points. This is a common part that is found across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until read more the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.