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 edge of the transmission just above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU uses this information to control the amount of fuel and boost. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor serves as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating chain stretch or a jumped link on the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky because there are two connector pins, and they have different functions but the best way to test it is to measure the resistance between the sensor and the ECU. If the sensor is functional, it should read approximately 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. This morning i pull out the spark plugs, three were drenched with gazoline the fourth was dry. I placed a tissue over each injector hole and when i start the engine with no sparks, the 3 that have gazoline pop right out. The fourth one remains closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero Ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but with no luck. The car is able to start if the G28 is not plugged in and runs fine when it is connected, but still has intermittent misfire issues 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 gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, i think i've pretty much eliminated everything else. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in here a wrecking shop website or a parts store. It is simple to test them - simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to know both the position and speed of the crankshaft in order to make a decision about fuel injector timing, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will show codes that could lead to the engine shutting down.
Some of the symptoms of a failing G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or a misfire when in gear. website It is likely that your sensor is failing and requires to be replaced if you notice any of these symptoms. They're inexpensive and easy to locate especially in the case of an Bosch unit like ours. Alternatively, GM's version of this part is a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of problems in your car. It's a vital component of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is turning. If the sensor click here fails, it could affect the performance of the transmission, as well as the other car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU uses this signal to control the flow of fuel and boost and also timig. It also sends it to the G5 Tachometer inside here the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Also, 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 a resistance of approximately 1000 ohms between these two points. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 DU So, you may find some good ones in wrecking yards.