How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located at the edge of transmission over the flywheel 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 sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU uses 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 link the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC, and where the camshaft lies in order to activate the spark and injectors.
If this sensor fails to function, the ECU will display a P00160 error message. This means that the Crank Shaft is not in 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 chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test since there are various pins on the connector, and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should read about 1000 ohms. Check for evidence of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or injectors aren't firing anymore. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was unclean. I put tissue over each hole in the injector and when I start the engine with no sparks, the three with gazoline jump out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero Ohm. I assume that the problem is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is unplugged, and 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 temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.
I'm not certain what to do, as i feel i have pretty much ruled out everything else. However, i'm afraid that I might have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style sender is identical to the G4 and they both work in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is easy to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They should 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 in order to make a decision about fuel injector timing etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes wrong, you will receive codes on the diagnostic scanner which can cause the engine to shut down.
A failing G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, and/or a misfire in the gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these signs. audi replacement key uk is that they are very cheap and readily available particularly in the case of the Bosch unit like ours. If you prefer, GM's version of this part is an excellent choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind a slew of issues with your vehicle. It is a crucial part of your Audi's transmission, as it sends information to the ECU about how the car's crankshaft is spinning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to control fuel, timig, and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should detect an average resistance of 1000 ohms between these points. This is a common part across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.