How to Replace an
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Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via an uncolored wire (T55/49), 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 the amount of fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors accordingly.
If this sensor fails when it fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult because there are two connector pins 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 about 1000 ohms when the sensor is at full operation. Look for signs 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 had an abrupt drop in power like the engine is running out of gas or injectors are not firing at all. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was unclean. When i crank the engine with no sparks, i place a tissue on top of each injector hole and the 3 drenched with gazoline pop out, but the 4th stay closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found zero ohm. I assume that the problem is in another location.
I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I'm not sure what to do. I think I've ruled everything else out. I'm concerned that i may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or a parts store. Test them out to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's end). They must be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to be aware of the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will display codes that could lead to an engine shut down.
The signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when you're in gear. It is likely that your sensor is failing and requires to be replaced if you notice any of these symptoms. The good news is they are very affordable and easy to find, especially in the case of an Bosch model, like ours. Alternatively, the GM version of this component is also a good choice.
5. Tachometer
A faulty engine speed sensor could be the cause of many issues in your vehicle. It's a crucial component of the transmission in your
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Crowncondor93.bravejournal.net) since it sends information to the ECU about how fast or slowly the engine of the car is spinning. If this sensor fails, it could disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU then uses and processes this signal to control fuel, timig and boost and then sends it on 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 check 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 see approximately 1000 ohms resistance between those two pins. This is a typical part across the
audi remote key 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.
