How to Replace an audi keyless entry G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission just above the flywheel gear. It sends a message to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using an uncolored wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends signals to the G5 tachometer in the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors according to the situation.

If this sensor fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).

It's a bit tricky to test since there are different connector pins, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor classicalmusicmp3freedownload.com is at full operation. If you're experiencing issues with this sensor, look for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll i had an abrupt drop in power as if the engine was running out of gas or injectors aren't firing anymore. In the morning, i removed the spark plugs, three were soaked with gazoline and the fourth was dry. I placed a tissue over each injector hole and when i start the engine without sparks, the 3 that have gazoline pop right 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 think the issue is in another location.

I also tried to reset the PID without success. The car can start when the G28 is unplugged and is running fine when it is plugged in, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.

I'm not sure what to do. I think I've all other possibilities out. But i am afraid i might 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 sent 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. It is easy to find the spare in a salvage shop or parts store. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). They must be infinite ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the position and speed of the crankshaft in order to make a decision about timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner which can lead to engine shutdown.

A failing G28 sensor could result in an inaccurate speed counter for the gearbox, a gearbox that shifts more quickly than normal, and/or a misfire in the gear. It is likely that your sensor is failing and needs to be replaced if you notice any of these symptoms. The good news is that they are quite affordable and readily available, especially when you're looking at the Bosch sensor, which is what we have. If you prefer, GM's version of this part would be an excellent choice.

5. Tachometer

A faulty engine speed sensor could be the cause of many issues with your car. It's an essential component of the audi key fob's transmission as it sends information to the ECU about how the car's crankshaft is rotating. If the sensor fails, it can disrupt the performance of the transmission and the other car's components.

The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It sends signals via gray wire to ECU pin T55/49. The ECU then processes this signal to control fuel, timig, and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 and pin T26a/12. It should show approximately 1000 ohms of resistance between those two pins. This is a common feature across the replacement audi key 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 DU, so you might find some good ones in wrecking yards.