10 Things You Learned In Kindergarden To Help You Get Started With Audi G28 How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician teaches 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 the ECU via the grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the location of the camshaft to trigger the spark and injectors.

If this sensor fails, the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft aren't in sync and could indicate chain stretch or a jumped link on the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky since there are two connector pins, and they perform different functions but the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should read about 1000 ohms. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had a big cut in power like the engine is running out of gas or the injectors aren't firing anymore. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was dry. audi key replacement near me placed a tissue over each injector hole, and when I start the engine with no sparks, the three 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'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 it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug 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 believe that I've eliminated everything else. I'm concerned that i may have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. advanced key audi -style transmitter is identical to the G4 and both are used in the 80 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. It is easy to test them: simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft to make a decision about fuel injector timing 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 can cause the engine to shut down.

A damaged G28 sensor could result in an inaccurate speed counter for your gearbox, a gearbox that shifts more quickly than normal, and/or a misfire while in the gear. It is probable that the sensor is failing and needs to be replaced if you encounter any of these signs. The good news is they are quite affordable and easily accessible particularly when you're looking at the Bosch sensor, like ours. If you prefer, GM's version of this part is an excellent choice.

5. Tachometer

A faulty engine speed sensor could be a cause for a slew of issues with your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is turning. This sensor could cause the transmission to malfunction and other components in the car to be affected.

The G5 engine speed sensor is situated on the outside of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal to control the amount of fuel and boost, as well as timig. It also sends it 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 via pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms between these two points. This part is common across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU So, you may find some good ones in wrecking yards.