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How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer within the instrument cluster.

The sensor is used to connect the G40 Camshaft position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the position of the camshaft, so that it can 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 and could indicate the chain is stretched or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

It can be a bit difficult to test because there are different pins on the connector, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. car key replacement audi should read around 1000 ohms when it is operating at its maximum. Look for evidence 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 a big cut in power as if the engine was running out of gas or injectors are not firing any more. I took out the spark plugs this morning, three were soaked in gasoline, and the fourth was unclean. When I start the engine, there are no sparks, I put a piece of tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stays shut. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.

I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.

I'm not sure what to do, as i think i've pretty much completely ruled out all other possibilities. However, i'm afraid that I may have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. It is simple to test them to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They should be infinite Ohms.





4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines requires to know both the position and speed the crankshaft in order to make a decision about timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these, the diagnostic scanner will show codes that could lead to the engine shutting down.

Some of the signs of a failed G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when in gear. It is possible that your sensor is failing and needs to be replaced if you encounter any of these signs. They are cheap and easy-to-find especially when they're an Bosch model like ours. You can also choose the GM version of this component is also a great option.

5. Tachometer

A failing engine speed sensor could be the cause of many issues in your vehicle. click through the next document 's a vital component of your Audi's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. If the sensor fails, it can disrupt the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig, and boost, and also sends it on to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those two pins. This is a typical part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.