How to Replace an audi new key G28 Engine Speed Sensor
In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated on the edge of the transmission, above the flywheel ring gear. It sends a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer in the instrument cluster.
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/11/happy-young-woman-with-key-sitting-in-new-car-2022-12-16-21-31-14-utc-min-scaled.jpg)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 through an uncolored wire. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 tachometer in the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must 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 display a P00160 error code. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumped 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 because there are various connector pins, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when the sensor is operating at its maximum. If you are having problems with this part, check for evidence of coolant or oil in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was unclean. I placed a tissue over each injector hole and when i start the engine without sparks, the three with gazoline jump out. The 4th one remains closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found 0ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID without success. The car will start when the G28 is unplugged and is running fine when it is plugged in, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for the coolant (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, i think i've pretty much eliminated everything else. But i'm worried that i might have missed something. If anyone has any ideas please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a parts store. It is simple to test them - just switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must know the speed and position of the crankshaft in order to make decisions regarding timing of the fuel injector, replacement key for audi a4 example. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shut down.
Some of the symptoms of a failing G28 sensor audi q3 Key include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when in gear. It is likely that your sensor is failing and needs to be replaced if you experience any of these symptoms. The good news is that they are very cheap and easy to find particularly if you're looking at the Bosch unit which is what we have. If you prefer, GM's version of this part would be a good option.
5. Tachometer
A failing engine sensor could cause a variety of issues within your vehicle. It's a crucial component of the transmission of your Audi q3 key because it relays information to the ECU on how fast or slowly the engine of the car is spinning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate fuel, timig, and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms between these points. This is a standard component across the audi key fobs 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/BMW-2020-New.png)
