4 Dirty Little Secrets About Audi G28 Industry Audi G28 Industry

How to Replace an Audi G28 Engine Speed Sensor

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

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an indication to the G5 Tachometer located in 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 where the camshaft lies in order to activate the spark and injectors.

If this sensor fails when it fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of sync 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. The code won't show without the additional information provided by other sensors (G4 or G40).

It's a bit 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. If the sensor is operational, it should be reading around 1000 ohms. If you are having problems with this component, look for evidence of oil or coolant 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 like the engine is running out of gas or the injectors are not firing any more. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. I placed a tissue over each hole in the injector and when I start the engine without sparks, the three that have gazoline pop right out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero Ohm. I think the issue is somewhere else.

I also tried to reset PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of 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, but i think i've pretty much eliminated everything else. But i am afraid I may have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sensor is identical to the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. It is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's end). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that has to know the position and speed of the crankshaft in order to make decisions regarding fuel injector more info timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you have a problem with either of these sensors, the diagnostic scanner will display codes that could lead to an engine shut down.

A failing G28 sensor could cause an inaccurate speed counter website for the gearbox or a gearbox that shifts faster than normal, or an unfire when in gear. It is probable that the sensor is failing and requires to be replaced if you encounter any of these signs. The good thing is that they are very cheap and easy to find particularly when you're audi lost key looking at an Bosch model, which is what we have. You can also choose the GM version of this unit is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a variety of issues in your vehicle. It's a vital component of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is rotating. If this sensor fails, it can cause problems click here for the transmission as well as the rest of the car's components.

The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It sends signals via gray wire to ECU pin T55/49. The more info ECU is then able to process this signal to control fuel, timig and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can test the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms of resistance between those two pins. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du, so you might find good ones in wrecking yards.