How to Replace an Audi G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located at the top of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference to correlate 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, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper chain of timing. However, the error code won't be displayed on its own without additional information from other sensors (G4 and G40).

It is a little tricky to test since there are different pins on the connector, and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms if the sensor is operating at its maximum. If you are having problems with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge decrease 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, three were soaked with gasoline and the fourth was unclean. When i crank the engine with no sparks, i place a tissue on the top of each of the injector holes, the 3 drenched with gazoline jump out but the 4th stay closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. So i assume the problem is somewhere else.

I also tried to reset PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However, the intermittent lost audi key misfire problem still occurs at higher RPM. The coolant temperature sensor (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 when the actual pressure is zero.

I'm not sure what to do. I think I've ruled everything else out. But i'm worried that I might have missed something. Please let me know if you have audi lost key replacement 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, audi a3 key replacement and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. It is simple to test them - put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's end). They should be infinite ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines requires website to know both the speed and position of the crankshaft to determine fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes bad you will get codes on the diagnostic scanner that could cause engine shut down.

A failing G28 sensor can cause an inaccurate speed counter for the gearbox or a gearbox that shifts more quickly than normal, or an unfire when in the gear. It is likely that your sensor click here is failing and needs to be replaced if you experience any of these symptoms. They are cheap and easy-to-find, especially if they're an Bosch model like ours. If you prefer, GM's version of this component is an option.

5. Tachometer

A failing engine sensor could cause a number of problems in your vehicle. It's a crucial component of the transmission of your Audi because it relays information to the ECU on how fast or slow the engine of the car is spinning. This sensor can cause the transmission to malfunction and other components in the car to be affected.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer in instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms between these points. This is a standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good parts could be found in wrecking yards.