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 to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 through a grey wire. The ECU uses this information to regulate boost and fuel. It also sends signals to the G5 tachometer inside 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 the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails, the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky as there are two different pins for the connector and they perform different functions however the best method of testing it is to measure the resistance between the sensor and the ECU. When the sensor is fully operational, it should read approximately 1000 ohms. Look for evidence of coolant or oil in the connector bay if you have problems 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 running out of gas or the injectors are not firing any more. This morning i pull out the spark plugs. Three were drenched with gazoline the 4th one was dry. When i crank the engine without sparks, I put a piece of tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stays shut. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. I assume that the problem is in another location.
I also tried to reset the PID without success. The car can start if the G28 is disconnected and it runs perfectly when it is connected, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when I crank up the engine.
I’m not certain what to do, i think i’ve pretty much ruled out everything else. But i’m worried that I might have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is the same as the G4 and both are used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. It is easy to test them – simply switch 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 must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to know both the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner that can lead to engine shutdown.
Some cost of audi key replacement the symptoms of a failing G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal, and/or a misfire when you are in gear. If you experience any of these problems, it is likely your sensor is deteriorating and requires Replacement Audi Key Fob. The good news is that they are very affordable and readily available, especially in the case of an Bosch unit which is what we have. Alternately, GM’s version this part would be a good option.
5. Tachometer
A malfunctioning engine sensor can cause a myriad of issues in your car. It is a crucial part of your audi car key cover‘s transmission, as it sends information to the ECU about how the car’s crankshaft is spinning. If the sensor fails, it will affect the performance of the transmission as well as the other car’s components.
The G5 engine speed sensor is located at the outside of the transmission, above the flywheel ring gear and sends a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then uses and processes this signal to control the flow of fuel, timig and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can test key for audi sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins 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 observe approximately 1000 ohms of resistance between these two points. This is a common component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.
