How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission, above the flywheel gear. It sends a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge 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 uses this information to regulate the amount of fuel and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors according to the situation.
If this sensor fails the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain is stretched or a jump link on the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test because there are different pins on the connector, and each has its own functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should read around 1000 ohms. Examine for evidence of coolant or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced a big cut in power like the engine is out of gas or the injectors are not firing anymore. This morning i pull out the spark plugs, three were soaked with gazoline and the fourth was dry. I put tissue over each injector hole and when I start the engine with no sparks, the three with gazoline jump right out. The fourth one remains closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get zero ohm. So i assume the problem is in another place.
I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of that is -49c even after unplugging it. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, but i believe that i've ruled out everything else. I'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from 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 so you can easily find one at a junkyard or at a parts store. Test My Web Site out - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know the position and speed the crankshaft to make decisions regarding timing of the fuel injector, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner that could cause engine shut down.
A failing G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, and/or an unfire when in gear. If you experience any of these issues, it is likely that your sensor is failing and needs replacing. The good thing is that they are very cheap and easy to find, especially if you're looking at the Bosch model, which is what ours are. Alternately, the GM version of this part is also a good choice.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems within your vehicle. audi replacement car keys is a crucial part of the Audi's transmission as it sends information to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear. It sends a signal to the ECU at pin T55/49 through an uncolored wire. The ECU is then able to process this signal to control fuel, timig and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is a common part that is found across the Audi 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones could be available in wrecking yards.