How to Replace an replacement Audi key cost uk G28 Engine Speed Sensor

In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission just above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) and then 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, the G28 Engine Speed Sensor sends a 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 an indication to the G5 Tachometer in instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors accordingly.

If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is out of sync with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).

Testing is a bit challenging since there are two pins for the connector and they perform different functions however the best way to test 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. If you're experiencing issues with this sensor, look for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at a high speed, audi Key shell i noticed a huge decrease in power. It was as if the engine was running out of gas. Or, my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the fourth was dry. I put tissue over each hole in the injector and when I start the engine without sparks, the 3 with gazoline jump out. The fourth one remains closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. Therefore, i think the issue is somewhere else.

I also tried to reset the PID with no success. The car will start if the G28 is unplugged and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.

I'm not sure what to do, i think i've pretty much ruled out everything else. However, i'm afraid that i might have missed something. If anyone has suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare audi key in a salvage shop or a parts store. It is easy to test them - simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know both the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go bad you will get codes on the diagnostic scanner that could cause engine shut down.

Some of the symptoms of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or misfiring when you are in gear. If you are experiencing any of these issues, it is likely that your sensor is going bad and should be replaced. The good thing is that they are very affordable and easily accessible, especially when you're looking at a Bosch sensor, which is what we have. Alternatively, the GM version of this unit is also a good choice.

5. Tachometer

A malfunctioning engine speed sensor could be a cause for numerous issues with your vehicle. It's a vital component of your Audi A1 keys's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it could disrupt the performance of the transmission as well as the rest of the car's components.

The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control the flow of fuel and boost and also to timigrate. It also sends it to the G5 Tachometer located in the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should detect a resistance of approximately 1000 ohms between these two points. This is a common feature across the programming audi key 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and the 1995 RS2 DU, so you might find them in wrecking yards.