How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated at the edge of transmission over the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control boost and fuel. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors in the right way.
If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and could indicate the chain is stretched or a jump link on the upper timing chain. The code won't 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 perform different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is operating at its maximum. Check for signs of coolant, or oil in the connector bay if you have problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced massive power loss like the engine is out of gas or the injectors aren't firing anymore. This morning i pull out the spark plugs, three were drenched in gazoline, the fourth was dry. When I crank the engine without sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th one stays closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 I get zero Ohm. I think the issue is in another location.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the website actual pressure is 0.0 when i rev the engine.
I don't know what to do. I believe that I've all other possibilities out. I'm concerned that i may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or a parts store. Testing them is easy by putting your DMM in resistance mode and measure the check here resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's side). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines must know the position and speed of the crankshaft to make decisions regarding timing of fuel injectors, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner that audi a1 key can lead to engine shutdown.
A malfunctioning G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, or an unfire when in the gear. If you experience any of these issues it is likely that your sensor is going bad and should be replaced. The good news is that they are very affordable and easy to find, especially in the case of a Bosch model, which is what ours are. Alternately, the GM version of this unit is also a good choice.
5. Tachometer
A failing engine sensor could cause a number of problems in your car. It's an essential component of the transmission in your Audi because it relays information to the ECU about how audi key programming near me fast or slowly the car's engine is spinning. If this sensor fails, it will cause problems for the transmission, as well as the other car's components.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate fuel, timig and boost and then sends it on to the G5 tachometer in the instrument cluster. You can test 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]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms between these points. This is a common feature across new audi car key the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du So, you may find them in wrecking yards.