Ask Me Anything: 10 Answers To Your Questions About Audi G28

How to Replace an Audi G28 Engine Speed Sensor

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

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control fuel, timig and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can start spark and injectors in the right way.

If this sensor fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

It can be a bit difficult to test as there are various pins on the connector, and each one has different 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 in full operation. Check for signs of coolant or oil in the connector bay if you are experiencing issues with this component.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a massive reduction in power. It was like the engine was running out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth one was dry. I placed a tissue over each injector hole and when i start the engine with no sparks, the ones with gazoline jump right out. The 4th one stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. Therefore, i think the issue is in another place.

I also tried to reset the PID without success. The car is able to start when the G28 is disconnected and it runs perfectly when it is plugged in however it has the intermittent misfire issue 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 pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not certain what to do, i believe that i've eliminated everything else. I'm afraid i may have missed something. If anyone has any ideas please share them! TIA!

3. audi replacement key fob of the g28 receives signals 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. You can easily find the spare in a salvage shop or a parts store. It is simple to test them by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They should be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to know the speed and position of the crankshaft to determine timing of the fuel injector, etc. It uses 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 display codes that could cause an engine shut down.

A damaged G28 sensor could result in an inaccurate speed counter for the gearbox, a gearbox that shifts faster than normal, and/or an unfire when in the gear. It is likely that your sensor is failing and requires to be replaced if you notice any of these symptoms. The good news is that they are very affordable and easily accessible particularly in the case of an Bosch model, which is what ours are. Alternatively, the GM version of this part is also a good choice.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of many issues in your car. It is an important part of the transmission in your Audi, as it transmits information to the ECU about how fast or slowly the engine is spinning. This sensor can cause the transmission to fail and other car components to be affected.

The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU then processes this signal to regulate the flow of fuel, timig and boost and then transmitting it to the G5 tachometer 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 examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 as well as pin T26a/12. It should show around 1000 ohms of resistance between those two pins. This is the same across the Audi 80-100-200-RS2 series, starting beginning with the 1985 MC and up to the 1997 UrS AN and the 1995 RS2 Du, so you might find good ones in wrecking yards.

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Pub: 18 Mar 2024 03:36 UTC
Views: 150