How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic 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 to the ECU via a grey wire T55/49, then to the tachometer located on 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 an electrical signal to ECU pin T55/49 using a grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.
If this sensor fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult as there are two different 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 operating at its maximum. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed I noticed a massive decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, three were drenched in gazoline, the fourth one was dry. I put tissue over each injector hole and when I start the engine without sparks, the three with gazoline jump right out. The 4th one remains closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. I assume that the problem is elsewhere.
I also tried to reset the PID without success. The car will start when replacement audi car key the G28 is unplugged, and it works fine when the G28 connected. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, as i believe that i've ruled out everything else. But i'm worried that I might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is simple to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that must know the position and speed of the crankshaft in order to make decisions about timing of the fuel injector, for example. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will display here codes that could cause an engine shut down.
Some of the symptoms of a failing G28 sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal and/or misfiring when you're in gear. If you have any of these issues, it is most likely that your sensor is failing and requires replacement. They're cheap and easy to find especially when they're a Bosch audi key replacement model like ours. Alternately, the GM version of this part is also a good option.
5. Tachometer
A failing engine speed sensor could be a cause for numerous issues with your car. It's an essential component of the transmission of your Audi, as it transmits information to the ECU about how fast or slow the car's engine is turning. This sensor can cause the transmission to fail and other components in the car to be here affected.
The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control fuel and boost, as well as timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin T55/49 of check here the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du, so you might find some good ones in wrecking yards.