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, above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49) and then to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using an uncolored wire. The ECU then uses this information to control the flow of fuel, timig 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 reached TDC, and the location of the camshaft to trigger the spark and injectors.
If this sensor 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 a chain stretch or a jump in the chain link of the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test because there are different connector pins, and they all have different functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should be reading about 1000 ohms. Look for evidence of coolant or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced a big cut in power like the engine is out of gas or the injectors are not firing at all. I took out the spark plugs this morning and found that 3 were drenched in gasoline and the 4th was dry. I put a piece of tissue over each injector hole, and when I start the engine with no sparks, the three with gazoline jump out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I'm assuming that the issue is elsewhere.
I replacement key for audi a4 also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value that is -49c even after unplugging it. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, but i believe that i've eliminated everything else. I'm worried that i might have missed something. If anyone has suggestions, please share them! audi replacement key uk TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style click here sender is the same as 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 audi replacement key is simple to test them - simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that needs to be aware of the speed and position of the crankshaft in order to make decisions regarding timing of audi a3 replacement key the fuel injector, for example. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.
A damaged G28 sensor could cause an inaccurate speed counter for your gearbox and a gearbox which shifts faster than normal, and/or an unfire when in gear. If you experience any of these issues, it is most likely that your sensor is deteriorating and needs replacing. The good thing is that they are very affordable and readily available particularly in the case of an Bosch sensor, like ours. If you prefer, GM's version of this part would be an option.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your vehicle. It's a vital component of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it could cause problems for the transmission, as well as the other car's components.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer located in the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. It should show approximately 1000 ohms resistance between those points. This is a common part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.