The 12 Most Unpleasant Types Of Audi G28 The Twitter Accounts That You Follow
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is situated at the top of the transmission, above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within 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 an uncolored wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also the location of the camshaft in order to activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumpy chain link in the upper timing chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
It can be a bit difficult to test since there are various pins on the connector and they all have different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should read about 1000 ohms. Check for signs of coolant or oil in the connector bay if you have issues with this part.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed I noticed a massive drop in power. It was like the engine had run out of gas. Or my injectors were not firing. This morning i pull out the spark plugs, 3 were drenched with gazoline the fourth one was dry. I placed a tissue over each injector hole and when i start the engine without sparks, the ones that have gazoline pop right out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID 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 still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.
I'm not certain what to do, i think i've pretty much completely ruled out all other possibilities. However, i'm afraid that I may 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 transmitter 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 wrecking yard or in a local parts store. It is easy to test them - simply put your DMM into resistance mode and measure 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 have an ECU that has to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injectors, etc. audi lost key utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will display codes that could lead to an engine shut down.
The signs of a malfunctioning G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or a misfire when you are in gear. If you are experiencing any of these issues it is likely that your sensor is deteriorating and requires replacement. They're cheap and easy to find particularly when they're a Bosch unit like ours. You can also choose the GM version of this part is also a good option.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of problems in your vehicle. It's a crucial component of the transmission in your Audi, as it transmits information to the ECU on how fast or slow the engine of the car is turning. If this sensor fails, it could affect the performance of the transmission as well as the other car's components.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits a signal via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between those two pins. This is a common part that is found across the Audi 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.